Academic literature on the topic 'Quantitative trait analyses'
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Journal articles on the topic "Quantitative trait analyses"
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Jiang, C., and Z. B. Zeng. "Multiple trait analysis of genetic mapping for quantitative trait loci." Genetics 140, no. 3 (July 1, 1995): 1111–27. http://dx.doi.org/10.1093/genetics/140.3.1111.
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Abstract We present in this paper models and statistical methods for performing multiple trait analysis on mapping quantitative trait loci (QTL) based on the composite interval mapping method. By taking into account the correlated structure of multiple traits, this joint analysis has several advantages, compared with separate analyses, for mapping QTL, including the expected improvement on the statistical power of the test for QTL and on the precision of parameter estimation. Also this joint analysis provides formal procedures to test a number of biologically interesting hypotheses concerning the nature of genetic correlations between different traits. Among the testing procedures considered are those for joint mapping, pleiotropy, QTL by environment interaction, and pleiotropy vs. close linkage. The test of pleiotropy (one pleiotropic QTL at a genome position) vs. close linkage (multiple nearby nonpleiotropic QTL) can have important implications for our understanding of the nature of genetic correlations between different traits in certain regions of a genome and also for practical applications in animal and plant breeding because one of the major goals in breeding is to break unfavorable linkage. Results of extensive simulation studies are presented to illustrate various properties of the analyses.
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Nichols, Krista M., Paul A. Wheeler, and Gary H. Thorgaard. "Quantitative Trait Loci Analyses for Meristic Traits in Oncorhynchus mykiss." Environmental Biology of Fishes 69, no. 1-4 (March 2004): 317–31. http://dx.doi.org/10.1023/b:ebfi.0000022905.72702.0e.
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Goffinet, Bruno, and Sophie Gerber. "Quantitative Trait Loci: A Meta-analysis." Genetics 155, no. 1 (May 1, 2000): 463–73. http://dx.doi.org/10.1093/genetics/155.1.463.
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Abstract This article presents a method to combine QTL results from different independent analyses. This method provides a modified Akaike criterion that can be used to decide how many QTL are actually represented by the QTL detected in different experiments. This criterion is computed to choose between models with one, two, three, etc., QTL. Simulations are carried out to investigate the quality of the model obtained with this method in various situations. It appears that the method allows the length of the confidence interval of QTL location to be consistently reduced when there are only very few “actual” QTL locations. An application of the method is given using data from the maize database available online at http://www.agron.missouri.edu/.
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Hardy, John, Danyah Trabzuni, and Mina Ryten. "Whole genome expression as a quantitative trait." Biochemical Society Transactions 37, no. 6 (November 19, 2009): 1276–77. http://dx.doi.org/10.1042/bst0371276.
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Surprisingly, whole genome analyses of complex human neurological and psychiatric disorders have revealed that many genetic risk factors are likely to influence gene expression rather than alter protein sequences. Previous analyses of neurological diseases have shown that genetic variability in gene expression levels of deposited proteins influence disease risk. With this background, we have embarked on a comprehensive project to determine the effects of common genetic variability on whole genome gene expression.
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Müller-Myhsok, B., and T. Grimm. "Linkage analysis and genetic models in dyslexia — considerations pertaining to discrete trait analysis and quantitative trait analyses." European Child & Adolescent Psychiatry 8, S3 (September 1999): S40—S42. http://dx.doi.org/10.1007/pl00010692.
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Wilcox, Marsha A., Diego F. Wyszynski, Carolien I. Panhuysen, Qianli Ma, Agustin Yip, John Farrell, and Lindsay A. Farrer. "Empirically derived phenotypic subgroups – qualitative and quantitative trait analyses." BMC Genetics 4, Suppl 1 (2003): S15. http://dx.doi.org/10.1186/1471-2156-4-s1-s15.
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Plomin, Robert, and Gerald E. McClearn. "Quantitative trait loci (QTL) analyses and alcohol-related behaviors." Behavior Genetics 23, no. 2 (March 1993): 197–211. http://dx.doi.org/10.1007/bf01067425.
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Baes, C., and N. Reinsch. "TIGER: A software system for fine-mapping quantitative trait loci." Archives Animal Breeding 51, no. 4 (October 10, 2008): 402–12. http://dx.doi.org/10.5194/aab-51-402-2008.
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Abstract. The localisation of quantitative trait loci which contribute significantly to phenotype variation of economically important traits in domestic species has become an important goal in animal genomics. Several such loci have been roughly identified using linkage analyses; however the focus has now shifted towards fine mapping and pinpointing causal mutations. In the context of a cooperative national research project, the software system TIGER was developed. TIGER is a UNIX script linking several individual Fortran programmes and is used for comprehensive variance component analysis of fine mapping data. Starting with raw genotype data, pedigree and marker map information and ending with a residual maximum likelihood-based test for each putative quantitative trait locus position, the software provides the user with an "all in one" package capable of linkage analysis, linkage disequilibrium analysis and combined linkage/linkage disequilibrium analysis. The software system has been employed in 4 fine mapping projects on 4 distinct cattle chromosomes.
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Xiong, Xinwei, Hui Yang, Bin Yang, Congying Chen, and Lusheng Huang. "Identification of quantitative trait transcripts for growth traits in the large scales of liver and muscle samples." Physiological Genomics 47, no. 7 (July 2015): 274–80. http://dx.doi.org/10.1152/physiolgenomics.00005.2015.
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Growth-related traits are economically important traits to the pig industry. Identification of causative gene and mutation responsible for growth-related QTL will facilitate the improvement of pig growth through marker-assisted selection. In this study, we applied whole genome gene expression and quantitative trait transcript (QTT) analyses in 497 liver and 586 longissimus dorsi muscle samples to identify candidate genes and dissect the genetic basis of pig growth in a white Duroc × Erhualian F2 resource population. A total of 20,108 transcripts in liver and 23,728 transcripts in muscle with expression values were used for association analysis between gene expression level and phenotypic value. At the significance threshold of P < 0.0005, we identified a total of 169 and 168 QTTs for nine growth-related traits in liver and muscle, respectively. We also found that some QTTs were correlated to more than one trait. The QTTs identified here showed high tissue specificity. We did not identify any QTTs that were associated with one trait in both liver and muscle. Through an integrative genomic approach, we identified SDR16C5 as the important candidate gene in pig growth trait. These findings contribute to further identification of the causative genes for porcine growth traits and facilitate improvement of pig breeding.
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HERNÁNDEZ-SÁNCHEZ, J., A. CHATZIPLI, D. BERALDI, J. GRATTEN, J. G. PILKINGTON, and J. M. PEMBERTON. "Mapping quantitative trait loci in a wild population using linkage and linkage disequilibrium analyses." Genetics Research 92, no. 4 (August 2010): 273–81. http://dx.doi.org/10.1017/s0016672310000340.
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SummaryHistorical information can be used, in addition to pedigree, traits and genotypes, to map quantitative trait locus (QTL) in general populations via maximum likelihood estimation of variance components. This analysis is known as linkage disequilibrium (LD) and linkage mapping, because it exploits both linkage in families and LD at the population level. The search for QTL in the wild population of Soay sheep on St. Kilda is a proof of principle. We analysed the data from a previous study and confirmed some of the QTLs reported. The most striking result was the confirmation of a QTL affecting birth weight that had been reported using association tests but not when using linkage-based analyses.
Dissertations / Theses on the topic "Quantitative trait analyses"
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Pita, Fabiano Veraldo da Costa. "Construction of the gametic covariance matrix for quantitative trait loci analyses in outbred populations." Universidade Federal de Viçosa, 2003. http://www.locus.ufv.br/handle/123456789/10501.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
A aplicação de análises de “Quantitative Trait Loci” (QTL) em populações exogâmicas é desafiadora porque pressuposições simplificadoras não podem ser aplicadas (por exemplo, os alelos QTL não podem ser assumidos fixados em diferentes famílias, o número de alelos QTL segregantes não é conhecido a priori, não há desequilíbrio de ligação entre um dado alelo marcador e um dado alelo QTL). Quando o efeito genotípico do QTL é assumido aleatório no modelo de análise, a matriz de covariância gamética deve ser calculada para a realização das análises em populações exogâmicas. A acurácia dessa matriz é importante para a obtenção de estimativas confiáveis da posição ou efeito do QTL em análises de mapeamento, ou de valores genotípicos em avaliação genética assistida por marcadores. O objetivo do primeiro estudo foi avaliar diferente estratégias já implementadas em programas computacionais (SO- LAR, LOKI, ESIP e MATVEC) para calcular a matriz de coeficientes Idênticos por Descendência (IBD), que é necessária para o mapeamento de QTL em populações exogâmicas. SOLAR utiliza um método baseado em regressão linear, LOKI e ESIP são ambos baseados em “reverse peeling” e o amostrador implementado em MAT VEC amostra indicadores de segregação. Um pedigree com estrutura F2 típica foi simulado com uma família F2 pequena (2 indivíduos) ou grande (20 indivíduos) e marcadores flanqueadores localizados a 2 cM, 5 cM ou 10 cM de distância um do outro, com o QTL localizado no meio do intervalo. A habilidade dessas estratégias em lidar com informações de marcadores perdidas foi avaliada assumindo um dos pais da geração F2 com ou sem informação de marcador. SOLAR nao estimou os coeficientes IBD corretamente para a maior parte das situações simuladas, enquanto que LOKI apre- sentou problemas quando o tamanho da família F2 era grande. ESIP e o amostrador em MATVEC apresentaram bom desempenho em todas as situacões simuladas, com estimativas de coeficientes IBD próximas aos coeficientes verdadeiros. Portanto, ESIP e MATVEC são os softwares mais indicados quando analises genéticas são realizadas em pedigrees com estruturas complexas. O objetivo do segundo estudo foi avaliar o efeito da utilização de uma melhor aproximação da inversa da matriz de covariância gamética para a avaliação genética de grandes populações de animais domésticos. Algoritmos eficientes, baseados no rastreamento dos alelos QTL de um indivíduo em relação aos de seus avós (Probabilidade de Descendência de um QTL - PDQ), podem ser usados para construir a inversa da matriz de covariância gamética diretamente. Mas essa inversa é uma aproximação quando há informação incompleta de marcador. Também, o calculo exato de PDQºs torna-se difícil quando a informação de marcador é incompleta. Nesse estudo, a inversa da matriz de covariãncia gamética para uma pop- ulação exogãmica simulada foi calculada usando o algoritmo eficiente, mas as PDQ's foram calculadas usando um algoritmo Monte Carlo Cadeia de Markov (MCMC). Essa inversa foi utilizada para predizer o valor genético dos indivíduos através de BLUP assistido por marcadores (MABLUP). O efeito dos cálculos de PDQ usando o algoritmo MCMC sobre a acurãcia da MABLUP foi avaliado com base na resposta a seleção realizada, calculada para o pedigree simulado. Os resultados mostraram que quando as PDQ’S foram estimadas usando MCMC a perda em resposta devido ao uso da inversa aproximada pode ser reduzida em aproximadamente 20%, enquanto que em estudos anteriores essa redução foi de 50%. Ainda, quando quatro marcadores bi-alélicos foram utilizados a resposta para MABLUP foi maior e a perda em re- sposta devido a marcadores com informação perdida foi menor, quando comparadas a situação onde apenas dois marcadores bi-alélicos foram utilizados.
The application of Quantitative Trait Loci (QTL) analyses in outbred population is challenging because simplified assumptions do not hold for these populations (e.g., the QTL alleles cannot be assumed fixed in different families, the number of QTL alleles segregating is not known a priori, there is not gametic phase disequilibrium between a given genetic marker allele and a QTL allele). When the QTL genotypic effect is assumed random, the gametic covariance matrix must be calculated to per- form QTL analyses in outbred populations. The accuracy of this matrix is important to obtain reliable estimates of QTL position or effect when applying QTL mapping, or QTL genotypic values when applying Marker Assisted Genetic Evaluation. The objective of the first study was to evaluate the different strategies already imple- mented in softwares (SOLAR, LOKI, ESIP and MATVEC) to calculate the matrix of identical by descent (IBD) coefficients, which is required for QTL mapping anal- ysis in outbred populations. SOLAR uses a regression method, LOKI and ESIP are both based on reverse peeling, and the MAT VEC sampler samples segregation in- dicators. A typical F2 pedigree was simulated with a small (2 offspring) or a large (20 offspring) F2 family, and the flanking markers were simulated 2 CM, 5 CM, or 10 CM apart, with the QTL located in the middle. The ability of these strategies to deal with missing genetic marker information was evaluated assuming one of the F2 parents with or without marker information. SOLAR failed to estimate the correct coefficients at almost all situations simulated, while LOKI showed problems when a large family was present in the pedigree. ESIP and MATVEC sampler performed well at all situations, providing IBD coefficients closed to the true ones. Therefore, ESIP and MATVEC are more indicated when genetic analysis are carried out on complex pedigree structures. The objective of the second study was to evaluate the effect of using a better approximation of the inverse of the gametic covariance matrix on the genetic evaluation of large livestock populations. Efficient algorithms, based on trac- ing the QTL alleles of an individual to its grandmother or grandfather (probability of descent a QTL - PDQ’s), can be used to construct the inverse of the gametic covari- ance matrix directly. But this inverse is an approximation when incomplete marker information is available. Also, computing the exact PDQ’s becomes difficult when marker information is incomplete. In this study, the inverse of the gametic covariance matrix for a simulated outbred pedigree was calculated using the efficient algorithm, but the PDQ’s were calculated using a Markov chain Monte Carlo (MCMC) algo- rithm. This inverse was used to calculate the predicted genetic value of individuals through Marker Assisted Best Linear Unbiased Prediction (MABLUP). The effect of PDQ calculations using the MCMC algorithm on MABLUP accuracy was evaluated based on the realized response to selection for the simulated pedigree. The results showed that by estimating the PDQ’s by MCMC the loss in response because of using an approximate inverse could be reduced to about 20%, while in previous studies this reduction was of 50%. Further, response to MABLUP was greater when four bi-allelic markers were used, and the loss in response due to missing markers was smaller in the case with four markers compared to when only two bi-allelic markers were used.
Tese importada do Alexandria
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Masri, Amer. "Use of quantitative trait loci (QTL) affecting muscling in sheep for breeding." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/9526.
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Breeding programmes that use elite sires with the best estimated breeding values for muscling traits have achieved significant improvement in lamb production in the UK. Further acceleration of the rate of genetic gain for the desirable production traits could be achieved using DNA marker-assisted selection (MAS) breeding strategies. The underlying causal genetic variants associated with improved muscling may be unknown and lying between a cluster of genes known as quantitative trait loci (QTL) or could be single nucleotide polymorphisms (SNP). LoinMAXTM, Texel muscling QTL (TM-QTL) and c.*1232G > A myostatin mutation were genetic variants that reported to be associated with improved muscling characteristics and hence subjected to further analysis in this project. It is essential before incorporating segregating genetic variants in any breeding scheme to comprehensively evaluate their effects on carcass traits. In-vivo scanning (ultrasound scanning (US) and computed tomography scanning (CT)), and carcass video image analyses (VIA) were used in the current studies. Objective VIAprediction weights of the carcass primal cuts could be the backbone of a value-based marketing system that is suggested to replace the current Meat and Livestock Commission (MLC) carcass grades for conformation scores (MLC-C) and fat class (MLC-F). The effect of a single copy of LoinMAXTM QTL (LM-QTL) compared to noncarriers was evaluated in UK crossbred lambs out of Scottish Mule ewes. M. longissimus lumborum (MLL) width, depth and area, as measured by CT scanning, were significantly greater in lambs heterozygous for LM-QTL compared to noncarriers. VIA detected a significant effect of the LM-QTL on the predicted weight of saleable meat yield in the loin primal cut (+2.2%; P < 0.05). The effects of the ovine c.*1232G > A myostatin mutation (MM), found on sheep chromosome 2, on carcass traits in heterozygous crossbred lambs sired by Texel and Poll Dorset rams were studied. Texel crossbred lambs carrying MM had increased loin depth and area. In both crossbred lambs, MM-carriers had significantly higher CT-estimated lean weight and proportion (2 to 4%) and muscle to bone ratios (by ~3%). Poll Dorset heterozygous crossbred animals had higher muscle to fat ratio (28%) and significantly lower fat-related measurements. The c.*1232G > A (MM) mutation as well as TM-QTL effects were evaluated in a different genetic background of Texel x Welsh Mountain crossbreed lambs. Carrying two copies of MM was associated with a significant positive effect on 8 week weight, a negative effect on ultrasound fat depth, a substantial decrease in MLC-fat score, positive impact on VIA-estimated weight of the hind leg, chump and loin primal cuts, as well as the muscularity of the hind leg and loin regions with greater loin muscle width, depth and area. Two copies of MM altered lambs‟ morphological traits with significantly wider carcasses across the shoulders, breast and hind legs and greater areas of the back view of the carcass when measured by VIA. TM-QTL significantly increased US-muscle depth and TM-QTL carriers had significantly greater loin muscle width and area measurements. Comparing TM-QTL genetic groups (homozygote allele carriers (TM/TM), heterozygote carriers of paternal and maternal origin of allele (TM/+ and +/TM, respectively) and homozygote non-carriers (+/+)) and TM-QTL mode of action were then studied. TM/TM carcasses were significantly heavier than non-carriers by 1.6 kg and scored higher conformation values when compared to heterozygote groups only. TM/+ lambs had significantly higher VIA-predicted weight and muscularity in the hind leg and loin, and higher loin dimensions relative to some other genotypic groups. The effect of TM-QTL on some carcass shape measurements was significant. TM-QTL mode of action results on the loin muscling traits supports the earlier reports of polar over dominance. In the light of growing calls to replace the current subjective carcass payment system with the objective VIA system that values the carcass according to the superiority of its cuts, I investigated the ability of US and CT measurements to predict the VIAestimated weights of the carcass primal cuts. Several prediction equations were examined but the best could be achieved when ultrasound measurement, CT linear measurements and live weight were fitted in the model. Since CT scanning information of elite sires is now being used for genetic selection for carcass merit, genetic parameters and genetic relationships between CT scanning measurements and post mortem traits (VIA and MLC-FC) were estimated. However, results were not sufficiently accurate to be of practical use due to lack of data.
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Poon, Fong-Yee. "Genetic architecture of neurogenesis in the adult mouse forebrain : insights from quantitative trait locus analyses." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50395.
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Neural stem cells and their precursors, collectively referred to as neural progenitor cells (NPCs), are present in discrete regions of the mature brain, namely the subgranular zone (SGZ) of the dentate gyrus, the subventricular zone (SVZ), and rostral migratory stream (RMS). These NPCs divide and give rise to new neurons in a process called adult neurogenesis. Genetic influence is a major determinant of adult neurogenesis. However, the genetic architecture underlying NPC proliferation and differentiation is poorly understood. My thesis aims to gain insights into the genes regulating NPC proliferation using a phenotypic-driven, genome-wide approach. I first examined nine inbred mouse strains housed in the same condition and across different ages from 60 days (P60) to 2 years. Wide inter-strain differences and negative impact of age on the number of NPCs were observed in the RMS. Genetic background had a significant effect on NPC proliferation and it also differentially influenced the effect of age on this process. The most dramatic inter-strain difference was detected at P60. Heritability estimated ~50% of the differences in NPC numbers were attributed to the genetic variation among the strains. I used quantitative trait locus (QTL) mapping to survey the entire genome for chromosomal segments referred to as QTLs that contribute to the phenotypic differences. Two panels of recombinant inbred strains, AXB/BXAs and BXDs, were employed for QTL mapping. Genetic variation in QTLs on chromosome (Chr) 6 and 11 were significantly associated with the differences in NPC numbers in the RMS. Additional analyses revealed potential interaction of Chr 6 QTL with other loci. These QTLs are hypothesized to harbor genes important for NPC proliferation and downstream experimentation is required to validate the function of these genes. As proof of concept, a candidate gene called Galanin receptor 2 (Galr2) in the Chr 11 QTL was demonstrated to be a pro-proliferative regulator of NPCs using in vitro techniques manipulating Galr2 expression and Galr2 knockout mice. In summary, I identified novel QTLs underlying NPC proliferation and these loci serve as starting points to identify genes (e.g. Galr2) critical to this process.Medicine, Faculty of
Medical Genetics, Department of
Graduate
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Silva, Franklin Magnum de Oliveira. "Integrative analyses of photosynthesis, plant growth, metabolite levels and enzyme activities in an introgression line population of Solanum pennellii." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/21421.
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Fundação de Amparo à Pesquisa do Estado de MInas Gerais
Para identificar regiões genômicas envolvidas na regulação de processos fisiológicos fundamentais, como fotossíntese, respiração e aqueles relacionados, uma população de ILs de Solanum pennellii em fundo genético de S. lycopersicum (M82) foi analisada. Foram estudados parâmetros fisiológicos, metabólicos e de crescimento, que vão desde troca gasosa (por exemplo, taxa de assimilação de CO 2 e condutância estomática), fluorescência da clorofila (por exemplo, taxa de transporte de elétrons e de extinção fotoquímica), bem como parâmetros de crescimento (por exemplo, taxa de crescimento relativo, matéria seca da raiz e parte aérea). Em paralelo, nós também analisamos, por meio de uma plataforma robotizada, os principais intermediários metabólicos (por exemplo, açúcares, amido, nitrato, aminoácidos e proteínas), e a atividade de nove enzimas representativas do metabolismo central do C e N. O objetivo do estudo foi: (1) combinar informações sobre as atividades enzimáticas e os níveis de metabólitos de caule, pecíolo e folha com a biomassa e rendimento de frutos; (2) através do estudo desses três órgãos interligados, examinar o quanto há de conectividade entre a atividade das enzimas e os níveis de metabólitos; (3) fornecer informações preditivas sobre as diferenças de particionamento do C e assimilação N inorgânico; (4) investigar a diversidade genética natural e identificar QTLs relacionados ao metabolimo central e a atividade enzimática no caule, pecíolo e folha. As análises dos dados permitiram a identificação de 67 QTL relacionados à parametros fisiológicos e metabólicos. Além disso, uma anotação abrangente e detalhada destas regiões permitiu apontar um total de 87 genes candidatos que possam controlar as características investigadas. Desses, 70 genes apresentou variantes alélicas relacionadas inserções de elementos transponíveis entre os dois genótipos parentais. As análises metabólicas e enzimática revelaram alta frequência de correlações positivas entre as enzymas, frequência moderada de correlações entre metabólitos relacionados, e baixa correlações entre a atividade das enzimas e os níveis de metabólitos. Tomados em conjunto, vapresentamos o maior estudo de parâmetros de fotossíntese e crescimento em plantas de tomate até à data. Os resultados permitiram a identificação de genes candidatos que podem estar envolvidos na regulação da fotossíntese, metabolismo primário e crescimento da planta, e fornece um recurso genético valioso para a compreensão dos mecanismos bioquímicos envolvidos na regulação do metabolismo primário em tomateiro.
To identify genomic regions involved in the regulation of fundamental physiological processes such as photosynthesis, respiration and underlying traits, a population of 71 Solanum pennellii introgression lines (ILs) in the genetic background of S. lycopersicum (M82) was analyzed. We determined IL phenotypes physiological, metabolic and growth related traits, ranging from gas- exchange parameters (e.g. CO 2 assimilation rates and stomatal conductance), chlorophyll fluorescence parameters (e.g. electron transport rate and photochemical quenching) as well as growth related traits (e.g. relative growth rate, shoot and root dry matter accumulation). In parallel, we also analyzed by robotized platform the major metabolic intermediates (e.g. sugars and starch), and the activities of nine representative enzymes from central C and N metabolism. We aimed: (1) combine information about enzyme activities and metabolite levels from stem, petiole and leaf with biomass and fruit yield; (2) by studying these three interconnected organs, examine how much connectivity exists between enzyme activities and metabolite levels; (3) provide predictive information about differences in C partitioning and inorganic N assimilation; (4) investigate the natural genetic diversity and identify QTL controlling variation of enzyme activities and metabolite levels in stem, petiole and leaf. Data analyses allowed identification of 67 physiological and metabolic QTL. Additionally, a comprehensive and detailed annotation of these regions allowed to point out a total of 87 candidate genes that might control the investigated traits. Out of those, 70 genes showed allelic variants related to differentially transposable element insertions pattern between both parental genotypes. Furthermore, the results revealed high frequency of positive correlations between enzyme activities, moderate frequency of correlations between related metabolites, and few correlations between enzyme activities and metabolite levels. Taken together, we present the largest study of photosynthetic and growth parameters in tomato plants to date. Our results allowed the identification of candidate genes that might be involved in the regulation of photosynthesis, primary metabolismo and plant growth, and provide an valuable genetic resource to understanding of the biochemical mechanisms involved in the regulation of primary metabolism in tomato plants.
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Shimomura, Koichiro. "Quantitative trait locus analysis of agronomic traits in weedy cucumber lines for breeding." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263362.
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Joehanes, Roby. "Multiple-trait multiple-interval mapping of quantitative-trait loci." Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1605.
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Conde-Martinez, F. Victor. "Quantitative trait loci and bulk segregant analysis to identify drought-related traits in maize (Zea mays L.)." Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432430.
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Yao, Ping. "Quantitative trait loci mapping and candidate gene analysis for growth and carcass traits on two bovine chromosomes." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4576.
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Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 7, 2009) Includes bibliographical references.
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Marklund, Lena. "Genome analysis of quantitative trait loci in the pig /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1997. http://epsilon.slu.se/avh/1997/91-576-5416-6.gif.
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Atkinson, Jennifer L. "Quantitative trait locus analysis of growth in Arabidopsis thaliana." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/11892.
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Natural genetic variation found among accessions of Arabidopsis thaliana presents the opportunity of locating and identifying novel genes by means of quantitative trait locus (QTL) analysis. In this study, QTL analysis was used to identify loci involved in the genetic control of growth in A. thaliana. Non-destructive methods of analysis were developed and used for the measurements of growth rates in roots and leaves, whilst a simple size measurement of mature petals was used to assess growth in the floral organ. Two putative QTL were identified for primary root length, four for leaf number at day 32 and three for petal size in the Bay-0 x Shahdara recombinant inbred line (RIL) population. The Landsberg erecta x Columbia RIL population was also analysed, but no significant QTL were identified. The analysis suggested that, in all three organs, growth-rate is controlled by multiple small-effect QTL and is a highly plastic trait. Thus, minor environmental fluctuations during the course of experiments can lead to a large environmental variance in measurement of the traits, limiting the power of QTL analyses. Despite minimising these effects by adjusting growth techniques, the numbers and significance of QTL identified in each trait were lower then expected, and for the trait of relative growth rate in leaves no significant QTL were identified.
Books on the topic "Quantitative trait analyses"
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Weller, Joel Ira. Quantitative trait loci analysis in animals. Oxon, UK: CABI Pub., 2001.
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Weller, J. I., ed. Quantitative trait loci analysis in animals. Wallingford: CABI, 2009. http://dx.doi.org/10.1079/9781845934675.0000.
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Weller, J. I., ed. Quantitative trait loci analysis in animals. Wallingford: CABI, 2001. http://dx.doi.org/10.1079/9780851994024.0000.
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Weller, Joel Ira. Quantitative trait loci analysis in animals. 2nd ed. Cambridge, MA: CABI North American Office, 2009.
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1957-, Walsh Bruce, ed. Genetics and analysis of quantitative traits. Sunderland, Mass: Sinauer, 1998.
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S, Pooni Harpal, ed. Th e genetical analysis of quantitative traits. Cheltenham: Stanley Thornes, 1998.
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Kearsey, Michael J., and Harpal S. Pooni. The Genetical Analysis of Quantitative Traits. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4899-4441-2.
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Lantbruksuniversitet, Sveriges, ed. Genome analysis of quantitative trait loci in the pig. Uppsala: Sveriges Lantbruksuniversitet, 1997.
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Sebastian, Rachel Louise. The genetic mapping and quantitative trait analysis of Brassica Oleracea. Birmingham: University of Birmingham, 2000.
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Hazardous materials transportation risk analysis: Quantitative approaches for truck and train. New York: Van Nostrand Reinhold, 1994.
Find full textBook chapters on the topic "Quantitative trait analyses"
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Nichols, Krista M., Paul A. Wheeler, and Gary H. Thorgaard. "Quantitative trait loci analyses for meristic traits in Oncorhynchus mykiss." In Genetics of Subpolar Fish and Invertebrates, 317–31. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-94-007-0983-6_26.
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Falchi, Mario. "Analysis of Quantitative Trait Loci." In Bioinformatics, 297–326. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-60327-429-6_16.
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Duffy, David L. "Analysis of Quantitative Trait Loci." In Methods in Molecular Biology, 191–203. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-6613-4_11.
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Xu, Shizhong. "Quantitative Trait-Associated Microarray Data Analysis." In Principles of Statistical Genomics, 383–94. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-0-387-70807-2_24.
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Amos, Christopher I., Bo Peng, Yaji Xu, and Jianzhong Ma. "Linkage Analysis of Quantitative Traits." In Handbook on Analyzing Human Genetic Data, 119–45. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-69264-5_4.
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Morota, Gota, Diego Jarquin, Malachy T. Campbell, and Hiroyoshi Iwata. "Statistical Methods for the Quantitative Genetic Analysis of High-Throughput Phenotyping Data." In Methods in Molecular Biology, 269–96. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2537-8_21.
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AbstractThe advent of plant phenomics, coupled with the wealth of genotypic data generated by next-generation sequencing technologies, provides exciting new resources for investigations into and improvement of complex traits. However, these new technologies also bring new challenges in quantitative genetics, namely, a need for the development of robust frameworks that can accommodate these high-dimensional data. In this chapter, we describe methods for the statistical analysis of high-throughput phenotyping (HTP) data with the goal of enhancing the prediction accuracy of genomic selection (GS). Following the Introduction in Sec. 1, Sec. 2 discusses field-based HTP, including the use of unoccupied aerial vehicles and light detection and ranging, as well as how we can achieve increased genetic gain by utilizing image data derived from HTP. Section 3 considers extending commonly used GS models to integrate HTP data as covariates associated with the principal trait response, such as yield. Particular focus is placed on single-trait, multi-trait, and genotype by environment interaction models. One unique aspect of HTP data is that phenomics platforms often produce large-scale data with high spatial and temporal resolution for capturing dynamic growth, development, and stress responses. Section 4 discusses the utility of a random regression model for performing longitudinal modeling. The chapter concludes with a discussion of some standing issues.
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Smith, Randy, Keith Sheppard, Keith DiPetrillo, and Gary Churchill. "Quantitative Trait Locus Analysis Using J/qtl." In Methods in Molecular Biology, 175–88. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-60761-247-6_10.
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Gadau, Jürgen, Christof Pietsch, and Leo W. Beukeboom. "Quantitative Trait Locus Analysis in Haplodiploid Hymenoptera." In Methods in Molecular Biology, 313–28. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-785-9_16.
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Sham, Pak. "Recent developments in quantitative trait loci analysis." In Behavioral genetics in the postgenomic era., 41–54. Washington: American Psychological Association, 2003. http://dx.doi.org/10.1037/10480-003.
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Sorensen, Daniel, and Daniel Gianola. "Introduction to Segregation and Quantitative Trait Loci Analysis." In Statistics for Biology and Health, 671–99. New York, NY: Springer New York, 2002. http://dx.doi.org/10.1007/0-387-22764-4_16.
Full textConference papers on the topic "Quantitative trait analyses"
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Cozzi, E., M. Prysak, and D. Beier. "Airway Hyperresponsiveness Quantitative Trait Linkage Analyses in Inbred and Outbred Mice." In American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California. American Thoracic Society, 2009. http://dx.doi.org/10.1164/ajrccm-conference.2009.179.1_meetingabstracts.a2749.
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Yang, I. V., J. Cardwell, W. Zhang, R. Borie, A. Walts, J. Powers, M. Rojas, P. J. Wolters, T. E. Fingerlin, and D. A. Schwartz. "Functional Validation of MUC5B and DSP Genetic Variants in Idiopathic Pulmonary Fibrosis (IPF) by Expression Quantitative Trait Locus (EQTL) and Co-Localization Analyses." In American Thoracic Society 2020 International Conference, May 15-20, 2020 - Philadelphia, PA. American Thoracic Society, 2020. http://dx.doi.org/10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a2256.
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Huh, Ik-Soo, Sohee Oh, Eunjin Lee, and Taesung Park. "Compairing quantitative trait analysis to qualitative trait analysis for complex traits disease: A genome wide association study for hyperlipidemia." In 2010 IEEE International Conference on Bioinformatics and Biomedicine Workshops (BIBMW). IEEE, 2010. http://dx.doi.org/10.1109/bibmw.2010.5703825.
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Boone, Edward L., Karl Ricanek, and Susan J. Simmons. "Quantitative Trait Loci Analysis Using a Bayesian Framework." In 2007 International Joint Conference on Neural Networks. IEEE, 2007. http://dx.doi.org/10.1109/ijcnn.2007.4371053.
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Gaidelys, Vaidas, and Emilija Naudžiūnaitė. "EVALUATION OF THE MATHEMATICAL MODELLING METHODS AVAILABLE IN THE MARKET." In 12th International Scientific Conference „Business and Management 2022“. Vilnius Gediminas Technical University, 2022. http://dx.doi.org/10.3846/bm.2022.725.
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The major purpose of this research is to analyse and select the relevant mathematical modelling methods that will be employed for developing an algorithm. To fulfil the major purpose, three following objectives were raised. First, to select and substantiate the most common mathematical modelling methods. Second, to test the pre-selected meth-ods under laboratory conditions so that the most relevant method for implementing the target project could be identi-fied. Third, to prepare at least 3 models for application. The research results indicate that when evaluating the respira-tory virus (SARS-CoV-2 causing COVID-19) concentration and survival rate dependence on a number of traits, the methods of descriptive statistics, confidence intervals, hypothesis testing, dispersion analysis, trait dependence analysis, and regression analysis are employed. All the above-listed methods were tested under laboratory conditions and thus can be applied to evaluate the effectiveness of the project product – a device designed to prevent transmission of res-piratory viruses through air droplets. Selection of a particular method depends on a set of traits to be analysed, a trait type (quantitative, qualitative), a trait distribution type, and parameters. In the context of COVID-19, there is an urgent need to bring new products to market. Since most of the new products developed are directly related to research, it is very important to calculate the algorithms required to provide the service. Therefore, in order to calculate the optimal algorithm, it is necessary to analyze the algorithms already on the market. In this way, the products developed can gain a competitive advantage over competitors’ products. Given that the equipment placed on the market will be equipped with HINS radiation sources, such a product will become original and new on the market. Therefore, it is necessary to evaluate several methods of mathematical modelling. It is also necessary to take into account that the placing on the market of a product takes place in the context of global competition.
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Grigorov, Tatiana. "Variabilitatea caracterelor biomorfologice la mutantul calcaroides de orz de primăvară în generațiile M3-M7." In VIIth International Scientific Conference “Genetics, Physiology and Plant Breeding”. Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2021. http://dx.doi.org/10.53040/gppb7.2021.39.
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The variability of quantitative traits (plant height, spike length, apical internode length, number of spikelets and grains per spike, number of productive tillers per plant) in barley calcaroides mutant of cv. Sonor induced by gamma rays (250 Gy) has been studied. The analysis of variance showed that year condi-tions were mainly responsible (10.59 to 46.96%) for variation of studied traits, followed by the genotype (1.48 to 20.5%) and the interaction of these factors (1.94 to 8.64%), with only one exception for number of grains per spike. Variation of this trait depends mostly on genotype factors. The mean values of all studied traits of mutant form were lower than of Sonor variety. This morphological mutant has a scientific importance.
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Vilela, Plínio, Mônica Cachoni, Anderson Vieira, and Luciano Christofoletti. "Train Circulation Planning: Quantitative Approaches." In 2017 Joint Rail Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/jrc2017-2223.
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The railway traffic system is an important player in passenger and freight transportation. This paper aims to present a survey of optimization models for the most commonly studied rail transportation problems related to train scheduling. We propose a classification of models and describe their characteristics by focusing on model structure and algorithmic aspects. Most reviewed papers have been proposed during the last decades. Apart from a few exceptions, the survey concentrates on published and easily accessible material. We have also elected to limit ourselves to contributions dealing specifically with rail transportation planning in single and double tracks. Each model has different goals, such as, to minimize service delays, to reduce the unscheduled train stops or to minimize the total time a train has to remain motionless, specially to allow crossings. For each group of problems, we propose a classification of models and describe their important characteristics by focusing on model structure and algorithmic aspects. The literature review involve papers published since the 1970s, but recent publications suggest that the problem is still heavily investigated. The main approaches considered are those that focus on Mathematical Optimization and Simulation. The review also considers the approach used to generate the solution, the type of railroad (real or hypothetical), and the infrastructure characteristics used to represent the railroad model. Our analysis focuses on showing an overview of those planning models.
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Lu, Hong, and Lu Lu. "Expression quantitative trait loci and genetic regulatory network analysis of Fbn1." In INTERNATIONAL SYMPOSIUM ON THE FRONTIERS OF BIOTECHNOLOGY AND BIOENGINEERING (FBB 2019). AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5110812.
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Purrington, Kristen S., Drakoulis Yannoukakos, Jane Carpenter, Heli Nevanlinna, Angela Cox, Gianluca Severi, Christine Ambrosone, et al. "Abstract 3266: Expression quantitative trait locus analysis of triple negative breast cancer." In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-3266.
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Dowling, Caroline. "Perfect Timing: Quantitative trait locus analysis of flowering time in Cannabis sativa." In ASPB PLANT BIOLOGY 2020. USA: ASPB, 2020. http://dx.doi.org/10.46678/pb.20.1053029.
Full textReports on the topic "Quantitative trait analyses"
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Weller, Joel I., Harris A. Lewin, and Micha Ron. Determination of Allele Frequencies for Quantitative Trait Loci in Commercial Animal Populations. United States Department of Agriculture, February 2005. http://dx.doi.org/10.32747/2005.7586473.bard.
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Individual loci affecting economic traits in dairy cattle (ETL) have been detected via linkage to genetic markers by application of the granddaughter design in the US population and the daughter design in the Israeli population. From these analyses it is not possible to determine allelic frequencies in the population at large, or whether the same alleles are segregating in different families. We proposed to answer this question by application of the "modified granddaughter design", in which granddaughters with a common maternal grandsire are both genotyped and analyzed for the economic traits. The objectives of the proposal were: 1) to fine map three segregating ETL previously detected by a daughter design analysis of the Israeli dairy cattle population; 2) to determine the effects of ETL alleles in different families relative to the population mean; 3) for each ETL, to determine the number of alleles and allele frequencies. The ETL on Bostaurusautosome (BT A) 6 chiefly affecting protein concentration was localized to a 4 cM chromosomal segment centered on the microsatellite BM143 by the daughter design. The modified granddaughter design was applied to a single family. The frequency of the allele increasing protein percent was estimated at 0.63+0.06. The hypothesis of equal allelic frequencies was rejected at p<0.05. Segregation of this ETL in the Israeli population was confirmed. The genes IBSP, SPP1, and LAP3 located adjacent to BM143 in the whole genome cattle- human comparative map were used as anchors for the human genome sequence and bovine BAC clones. Fifteen genes within 2 cM upstream of BM143 were located in the orthologous syntenic groups on HSA4q22 and HSA4p15. Only a single gene, SLIT2, was located within 2 cM downstream of BM143 in the orthologous HSA4p15 region. The order of these genes, as derived from physical mapping of BAC end sequences, was identical to the order within the orthologous syntenic groups on HSA4: FAM13A1, HERC3. CEB1, FLJ20637, PP2C-like, ABCG2, PKD2. SPP, MEP, IBSP, LAP3, EG1. KIAA1276, HCAPG, MLR1, BM143, and SLIT2. Four hundred and twenty AI bulls with genetic evaluations were genotyped for 12 SNPs identified in 10 of these genes, and for BM143. Seven SNPs displayed highly significant linkage disequilibrium effects on protein percentage (P<0.000l) with the greatest effect for SPP1. None of SNP genotypes for two sires heterozygous for the ETL, and six sires homozygous for the ETL completely corresponded to the causative mutation. The expression of SPP 1 and ABCG2 in the mammary gland corresponded to the lactation curve, as determined by microarray and QPCR assays, but not in the liver. Anti-sense SPP1 transgenic mice displayed abnormal mammary gland differentiation and milk secretion. Thus SPP 1 is a prime candidate gene for this ETL. We confirmed that DGAT1 is the ETL segregating on BTA 14 that chiefly effects fat concentration, and that the polymorphism is due to a missense mutation in an exon. Four hundred Israeli Holstein bulls were genotyped for this polymorphism, and the change in allelic frequency over the last 20 years was monitored.
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Weller, Joel I., Ignacy Misztal, and Micha Ron. Optimization of methodology for genomic selection of moderate and large dairy cattle populations. United States Department of Agriculture, March 2015. http://dx.doi.org/10.32747/2015.7594404.bard.
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The main objectives of this research was to detect the specific polymorphisms responsible for observed quantitative trait loci and develop optimal strategies for genomic evaluations and selection for moderate (Israel) and large (US) dairy cattle populations. A joint evaluation using all phenotypic, pedigree, and genomic data is the optimal strategy. The specific objectives were: 1) to apply strategies for determination of the causative polymorphisms based on the “a posteriori granddaughter design” (APGD), 2) to develop methods to derive unbiased estimates of gene effects derived from SNP chips analyses, 3) to derive optimal single-stage methods to estimate breeding values of animals based on marker, phenotypic and pedigree data, 4) to extend these methods to multi-trait genetic evaluations and 5) to evaluate the results of long-term genomic selection, as compared to traditional selection. Nearly all of these objectives were met. The major achievements were: The APGD and the modified granddaughter designs were applied to the US Holstein population, and regions harboring segregating quantitative trait loci (QTL) were identified for all economic traits of interest. The APGD was able to find segregating QTL for all the economic traits analyzed, and confidence intervals for QTL location ranged from ~5 to 35 million base pairs. Genomic estimated breeding values (GEBV) for milk production traits in the Israeli Holstein population were computed by the single-step method and compared to results for the two-step method. The single-step method was extended to derive GEBV for multi-parity evaluation. Long-term analysis of genomic selection demonstrated that inclusion of pedigree data from previous generations may result in less accurate GEBV. Major conclusions are: Predictions using single-step genomic best linear unbiased prediction (GBLUP) were the least biased, and that method appears to be the best tool for genomic evaluation of a small population, as it automatically accounts for parental index and allows for inclusion of female genomic information without additional steps. None of the methods applied to the Israeli Holstein population were able to derive GEBV for young bulls that were significantly better than parent averages. Thus we confirm previous studies that the main limiting factor for the accuracy of GEBV is the number of bulls with genotypes and progeny tests. Although 36 of the grandsires included in the APGD were genotyped for the BovineHDBeadChip, which includes 777,000 SNPs, we were not able to determine the causative polymorphism for any of the detected QTL. The number of valid unique markers on the BovineHDBeadChip is not sufficient for a reasonable probability to find the causative polymorphisms. Complete resequencing of the genome of approximately 50 bulls will be required, but this could not be accomplished within the framework of the current project due to funding constraints. Inclusion of pedigree data from older generations in the derivation of GEBV may result is less accurate evaluations.
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Paran, Ilan, and Molly Jahn. Analysis of Quantitative Traits in Pepper Using Molecular Markers. United States Department of Agriculture, January 2000. http://dx.doi.org/10.32747/2000.7570562.bard.
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Original objectives: The overall goal of the proposal was to determine the genetic and molecular control of pathways leading to the production of secondary metabolites determining major fruit quality traits in pepper. The specific objectives were to: (1) Generate a molecular map of pepper based on simple sequence repeat (SSR) markers. (2) Map QTL for capsaicinoids content (3) Determine possible association between capsaicinoids and carotenoid content and structural genes for capsaicinoid and carotenoid biosynthesis. (4) Map QTL for quantitative traits controlling additional fruit traits. (5) Map fruit-specific ESTs and determine possible association with fruit QTL (6) Map the C locus that determines the presence and absence of capsaicinoids in pepper fruit and identify candidate genes for C. Background: Pungency, color, fruit shape and fruit size are among the most important fruit quality characteristics of pepper. Despite the importance of the pepper crop both in the USA and Israel, the genetic basis of these traits was only little known prior to the studies conducted in the present proposal. In addition, molecular tools for use in pepper improvement were lacking. Major conclusions and achievements: Our studies enabled the development of a saturated genetic map of pepper that includes numerous simple sequence repeat (SSR) markers and the integration of several independent maps into a single resource map that consists of over 2000 markers. Unlike previous maps that consisted mostly of tomato-originated RFLP markers, the SSR-based map consists of largely pepper markers. Therefore, the SSR and integrated maps provide ample of tools for use in marker-assisted selection for diverse targets throughout the Capsicum genome. We determined the genetic and molecular bases of qualitative and quantitative variation of pungency, the most unique characteristics of pepper fruit. We mapped and subsequently cloned the Pun1 gene that serves as a master key for capsaicinoids accumulation and showed that it is an acyltransferase. By sequencing the Pun1 gene in pungent and non-pungent cultivars we identified a deletion that abolishes the expression of the gene in the latter cultivars. We also identified QTLs that control capsaicinoids content and therefore pungency level. These genes will allow pepper breeders to manipulate the level of pungency for specific agricultural and industrial purposes. In addition to pungency we identified genes and QTLs that control other key developmental processes of fruit development such as color, texture and fruit shape. The A gene controlling anthocyanin accumulation in the immature fruit was found as the ortholog of the petunia transcription factor Anthocyanin2. The S gene required for the soft flesh and deciduous fruit nature typical of wild peppers was identified as the ortholog of tomato polygalacturonase. We identified two major QTLs controlling fruit shape, fs3.1 and fs10.1, that differentiate between elongated and blocky and round fruit shapes, respectively. Scientific and agricultural implications: Our studies allowed significant advancement of our understanding at the genetic and molecular levels of important processes of pepper fruit development. Concomitantly to gaining biological knowledge, we were able to develop molecular tools that can be implemented for pepper improvement.
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Weller, Joel I., Derek M. Bickhart, Micha Ron, Eyal Seroussi, George Liu, and George R. Wiggans. Determination of actual polymorphisms responsible for economic trait variation in dairy cattle. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600017.bard.
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The project’s general objectives were to determine specific polymorphisms at the DNA level responsible for observed quantitative trait loci (QTLs) and to estimate their effects, frequencies, and selection potential in the Holstein dairy cattle breed. The specific objectives were to (1) localize the causative polymorphisms to small chromosomal segments based on analysis of 52 U.S. Holstein bulls each with at least 100 sons with high-reliability genetic evaluations using the a posteriori granddaughter design; (2) sequence the complete genomes of at least 40 of those bulls to 20 coverage; (3) determine causative polymorphisms based on concordance between the bulls’ genotypes for specific polymorphisms and their status for a QTL; (4) validate putative quantitative trait variants by genotyping a sample of Israeli Holstein cows; and (5) perform gene expression analysis using statistical methodologies, including determination of signatures of selection, based on somatic cells of cows that are homozygous for contrasting quantitative trait variants; and (6) analyze genes with putative quantitative trait variants using data mining techniques. Current methods for genomic evaluation are based on population-wide linkage disequilibrium between markers and actual alleles that affect traits of interest. Those methods have approximately doubled the rate of genetic gain for most traits in the U.S. Holstein population. With determination of causative polymorphisms, increasing the accuracy of genomic evaluations should be possible by including those genotypes as fixed effects in the analysis models. Determination of causative polymorphisms should also yield useful information on gene function and genetic architecture of complex traits. Concordance between QTL genotype as determined by the a posteriori granddaughter design and marker genotype was determined for 30 trait-by-chromosomal segment effects that are segregating in the U.S. Holstein population; a probability of <10²⁰ was used to accept the null hypothesis that no segregating gene within the chromosomal segment was affecting the trait. Genotypes for 83 grandsires and 17,217 sons were determined by either complete sequence or imputation for 3,148,506 polymorphisms across the entire genome. Variant sites were identified from previous studies (such as the 1000 Bull Genomes Project) and from DNA sequencing of bulls unique to this project, which is one of the largest marker variant surveys conducted for the Holstein breed of cattle. Effects for stature on chromosome 11, daughter pregnancy rate on chromosome 18, and protein percentage on chromosome 20 met 3 criteria: (1) complete or nearly complete concordance, (2) nominal significance of the polymorphism effect after correction for all other polymorphisms, and (3) marker coefficient of determination >40% of total multiple-regression coefficient of determination for the 30 polymorphisms with highest concordance. The missense polymorphism Phe279Tyr in GHR at 31,909,478 base pairs on chromosome 20 was confirmed as the causative mutation for fat and protein concentration. For effect on fat percentage, 12 additional missensepolymorphisms on chromosome 14 were found that had nearly complete concordance with the suggested causative polymorphism (missense mutation Ala232Glu in DGAT1). The markers used in routine U.S. genomic evaluations were increased from 60,000 to 80,000 by adding markers for known QTLs and markers detected in BARD and other research projects. Objectives 1 and 2 were completely accomplished, and objective 3 was partially accomplished. Because no new clear-cut causative polymorphisms were discovered, objectives 4 through 6 were not completed.
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Hulata, Gideon, and Graham A. E. Gall. Breed Improvement of Tilapia: Selective Breeding for Cold Tolerance and for Growth Rate in Fresh and Saline Water. United States Department of Agriculture, November 2003. http://dx.doi.org/10.32747/2003.7586478.bard.
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The main objective of this project was to initiate a breeding program to produce cold-tolerant and salinity-tolerant synthetic breeds of tilapia, from a base population consisting of a four-species hybrid population created under an earlier BARD project. A secondary objective was to estimate genetic parameters for the traits growth rate under fresh- and salt-water and for cold tolerance. A third objective was to place quantitative trait loci that affect these traits of interest (e.g., growth rate in fresh-water, salt-water and cold tolerance) on the growing linkage map of primarily microsatellite loci. We have encountered fertility problems that were apparently the result of the complex genetic structure of this base population. The failure in producing the first generation of the breeding program has forced us to stop the intended breeding program. Thus, upon approval of BARD office, this objective was dropped and during the last year we have focused on the secondary objective of the original project during the third year of the project, but failed to perform the intended analysis to estimate genetic parameters for the traits of interest. We have succeeded, however, to strengthen the earlier identification of a QTL for cold tolerance by analyzing further segregating families. The results support the existence of a QTL for cold tolerance on linkage group 15, corresponding to UNH linkage group 23. The results also indicate a QTL for the same trait on linkage group 12, corresponding to UNH linkage group 4.
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Sherman, Amir, Rebecca Grumet, Ron Ophir, Nurit Katzir, and Yiqun Weng. Whole genome approach for genetic analysis in cucumber: Fruit size as a test case. United States Department of Agriculture, December 2013. http://dx.doi.org/10.32747/2013.7594399.bard.
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The Cucurbitaceae family includes a broad array of economically and nutritionally important crop species that are consumed as vegetables, staple starches and desserts. Fruit of these species, and types within species, exhibit extensive diversity as evidenced by variation in size, shape, color, flavor, and others. Fruit size and shape are critical quality determinants that delineate uses and market classes and are key traits under selection in breeding programs. However, the underlying genetic bases for variation in fruit size remain to be determined. A few species the Cucurbitaceae family were sequenced during the time of this project (cucumber was already sequenced when the project started watermelon and melon sequence became available during the project) but functional genomic tools are still missing. This research program had three major goals: 1. Develop whole genome cucumber and melon SNP arrays. 2. Develop and characterize cucumber populations segregating for fruit size. 3. Combine genomic tools, segregating populations, and phenotypic characterization to identify loci associated with fruit size. As suggested by the reviewers the work concentrated mostly in cucumber and not both in cucumber and melon. In order to develop a SNP (single nucleotide polymorphism) array for cucumber, available and newly generated sequence from two cucumber cultivars with extreme differences in shape and size, pickling GY14 and Chinese long 9930, were analyzed for variation (SNPs). A large set of high quality SNPs was discovered between the two parents of the RILs population (GY14 and 9930) and used to design a custom SNP array with 35000 SNPs using Agilent technology. The array was validated using 9930, Gy14 and F1 progeny of the two parents. Several mapping populations were developed for linkage mapping of quantitative trait loci (QTL) for fruit size These includes 145 F3 families and 150 recombinant inbred line (RILs F7 or F8 (Gy14 X 9930) and third population contained 450 F2 plants from a cross between Gy14 and a wild plant from India. The main population that was used in this study is the RILs population of Gy14 X 9930. Phenotypic and morphological analyses of 9930, Gy14, and their segregating F2 and RIL progeny indicated that several, likely independent, factors influence cucumber fruit size and shape, including factors that act both pre-anthesis and post-pollination. These include: amount, rate, duration, and plane of cell division pre- and post-anthesis and orientation of cell expansion. Analysis of F2 and RIL progeny indicated that factors influencing fruit length were largely determined pre-anthesis, while fruit diameter was more strongly influenced by environment and growth factors post-anthesis. These results suggest involvement of multiple genetically segregating factors expected to map independently onto the cucumber genome. Using the SNP array and the phenotypic data two major QTLs for fruit size of cucumber were mapped in very high accuracy (around 300 Kb) with large set of markers that should facilitate identification and cloning of major genes that contribute to fruit size in cucumber. In addition, a highly accurate haplotype map of all RILS was created to allow fine mapping of other traits segregating in this population. A detailed cucumber genetic map with 6000 markers was also established (currently the most detailed genetic map of cucumber). The integration of genetics physiology and genomic approaches in this project yielded new major infrastructure tools that can be used for understanding fruit size and many other traits of importance in cucumber. The SNP array and genetic population with an ultra-fine map can be used for future breeding efforts, high resolution mapping and cloning of traits of interest that segregate in this population. The genetic map that was developed can be used for other breeding efforts in other populations. The study of fruit development that was done during this project will be important in dissecting function of genes that that contribute to the fruit size QTLs. The SNP array can be used as tool for mapping different traits in cucumber. The development of the tools and knowledge will thus promote genetic improvement of cucumber and related cucurbits.
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Feldman, Moshe, Eitan Millet, Calvin O. Qualset, and Patrick E. McGuire. Mapping and Tagging by DNA Markers of Wild Emmer Alleles that Improve Quantitative Traits in Common Wheat. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7573081.bard.
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The general goal was to identify, map, and tag, with DNA markers, segments of chromosomes of a wild species (wild emmer wheat, the progenitor of cultivated wheat) determining the number, chromosomal locations, interactions, and effects of genes that control quantitative traits when transferred to a cultivated plant (bread wheat). Slight modifications were introduced and not all objectives could be completed within the human and financial resources available, as noted with the specific objectives listed below: 1. To identify the genetic contribution of each of the available wild emmer chromosome-arm substitution lines (CASLs) in the bread wheat cultivar Bethlehem for quantitative traits, including grain yield and its components and grain protein concentration and yield, and the effect of major loci affecting the quality of end-use products. [The quality of end-use products was not analyzed.] 2. To determine the extent and nature of genetic interactions (epistatic effects) between and within homoeologous groups 1 and 7 for the chromosome arms carrying "wild" and "cultivated" alleles as expressed in grain and protein yields and other quantitative traits. [Two experiments were successful, grain protein concentration could not be measured; data are partially analyzed.] 3. To derive recombinant substitution lines (RSLs) for the chromosome arms of homoeologous groups 1 and 7 that were found previously to promote grain and protein yields of cultivated wheat. [The selection of groups 1 and 7 tons based on grain yield in pot experiments. After project began, it was decided also to derive RSLs for the available arms of homoeologous group 4 (4AS and 4BL), based on the apparent importance of chromosome group 4, based on early field trials of the CASLs.] 4. To characterize the RSLs for quantitative traits as in objective 1 and map and tag chromosome segments producing significant effects (quantitative trait loci, QTLs by RFLP markers. [Producing a large population of RSLs for each chromosome arm and mapping them proved more difficult than anticipated, low numbers of RSLs were obtained for two of the chromosome arms.] 5. To construct recombination genetic maps of chromosomes of homoeologous groups 1 and 7 and to compare them to existing maps of wheat and other cereals [Genetic maps are not complete for homoeologous groups 4 and 7.] The rationale for this project is that wild species have characteristics that would be valuable if transferred to a crop plant. We demonstrated the sequence of chromosome manipulations and genetic tests needed to confirm this potential value and enhance transfer. This research has shown that a wild tetraploid species harbors genetic variability for quantitative traits that is interactive and not simply additive when introduced into a common genetic background. Chromosomal segments from several chromosome arms improve yield and protein in wheat but their effect is presumably enhanced when combination of genes from several segments are integrated into a single genotype in order to achieve the benefits of genes from the wild species. The interaction between these genes and those in the recipient species must be accounted for. The results of this study provide a scientific basis for some of the disappointing results that have historically obtained when using wild species as donors for crop improvement and provide a strategy for further successes.
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Seroussi, Eyal, and George Liu. Genome-Wide Association Study of Copy Number Variation and QTL for Economic Traits in Holstein Cattle. United States Department of Agriculture, September 2010. http://dx.doi.org/10.32747/2010.7593397.bard.
Full textAbstract:
Copy number variation (CNV) has been recently identified in human and other mammalian genomes and increasing awareness that CNV might be a major source for heritable variation in complex traits has emerged. Despite this, little has been published on CNVs in Holsteins. In order to fill this knowledge-gap, we proposed a genome-wide association study between quantitative trait loci (QTL) for economic traits and CNV in the Holstein cattle. The approved feasibility study was aimed at the genome-wide characterization of CNVs in Holstein cattle and at the demonstrating of their possible association with economic traits by performing the activities of preparation of DNA samples, Comparative Genomic Hybridization (CGH), initial association study between CNVs and production traits and characterization of CNVSNP associations. For both countries, 40 genomic DNA samples of bulls representing the extreme sub-populations for economically important traits were CGH analyzed using the same reference genome on a NimbleGen tiling array. We designed this array based on the latest build of the bovine genome (UMD3) with average probe spacing of 1150 bases (total number of probes was 2,166,672). Two CNV gene clusters, PLA2G2D on BTA2 and KIAA1683 on BTA7 revealed significant association with milk percentage and cow fertility, respectively, and were chosen for further characterization and verification in a larger sample using other methodologies including sequencing, tag SNPs and real time PCR (qPCR). Comparison between these four methods indicated that there is under estimation of the number of CNV loci in Holstein cattle and their complexity. The variation in sequence between different copies seemed to affect their functionality and thus the hybridization based methods were less informative than the methods that are based on sequencing. We thus conclude that large scale sequencing effort complemented by array CGH should be considered to better detect and characterize CNVs in order to effectively employ them in marker-assisted selection.
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Fallik, Elazar, Robert Joly, Ilan Paran, and Matthew A. Jenks. Study of the Physiological, Molecular and Genetic Factors Associated with Postharvest Water Loss in Pepper Fruit. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7593392.bard.
Full textAbstract:
The fruit of pepper (Capsicum annuum) commonly wilts (or shrivels) during postharvest storage due to rapid water loss, a condition that greatly reduces its shelf life and market value. The fact that pepper fruit are hollow, and thus have limited water content, only exacerbates this problem in pepper. The collaborators on this project completed research whose findings provided new insight into the genetic, physiological, and biochemical basis for water loss from the fruits of pepper (Capsicum annuum and related Capsicum species). Well-defined genetic populations of pepper were used in this study, the first being a series of backcross F₁ and segregating F₂, F₃, and F₄ populations derived from two original parents selected for having dramatic differences in fruit water loss rate (very high and very low water loss). The secondly population utilized in these studies was a collection of 50 accessions representing world diversity in both species and cultivar types. We found that an unexpectedly large amount of variation was present in both fruit wax and cutin composition in these collections. In addition, our studies revealed significant correlations between the chemical composition of both the fruit cuticular waxes and cutin monomers with fruit water loss rate. Among the most significant were that high alkane content in fruit waxes conferred low fruit water loss rates and low permeability in fruit cuticles. In contrast, high amounts of terpenoids (plus steroidal compounds) were associated with very high fruit water loss and cuticle permeability. These results are consistent with our models that the simple straight chain alkanes pack closely together in the cuticle membrane and obstruct water diffusion, whereas lipids with more complex 3-dimensional structure (such as terpenoids) do not pack so closely, and thus increase the diffusion pathways. The backcross segregating populations were used to map quantitative trait loci (QTLs) associated with water loss (using DART markers, Diversity Arrays Technology LTD). These studies resulted in identification of two linked QTLs on pepper’s chromosome 10. Although the exact genetic or physiological basis for these QTLs function in water loss is unknown, the genotypic contribution in studies of near-isogenic lines selected from these backcross populations reveals a strong association between certain wax compounds, the free fatty acids and iso-alkanes. There was also a lesser association between the water loss QTLs with both fruit firmness and total soluble sugars. Results of these analyses have revealed especially strong genetic linkages between fruit water loss, cuticle composition, and two QTLs on chromosome 10. These findings lead us to further speculate that genes located at or near these QTLs have a strong influence on cuticle lipids that impact water loss rate (and possibly, whether directly or indirectly, other traits like fruit firmness and sugar content). The QTL markers identified in these studies will be valuable in the breeding programs of scientists seeking to select for low water loss, long lasting fruits, of pepper, and likely the fruits of related commodities. Further work with these newly developed genetic resources should ultimately lead to the discovery of the genes controlling these fruit characteristics, allowing for the use of transgenic breeding approaches toward the improvement of fruit postharvest shelf life.
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Wisniewski, Michael E., Samir Droby, John L. Norelli, Noa Sela, and Elena Levin. Genetic and transcriptomic analysis of postharvest decay resistance in Malus sieversii and the characterization of pathogenicity effectors in Penicillium expansum. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7600013.bard.
Full textAbstract:
Blue mold of apple caused by Penicilliumexpansumis a major postharvest disease. Selection for postharvest disease resistance in breeding programs has been ignored in favor of fruit quality traits such as size, color, taste, etc. The identification of postharvest disease resistance as a heritable trait would represent a significant accomplishment and has not been attempted in apple. Furthermore, insight into the biology of the pathogenicity of P. expansumin apple could provide new approaches to postharvest decay management. Hypothesis: Postharvest resistance of apple to P. expansumcan be mapped to specific genetic loci and significant quantitative-trait-loci (QTLs) can be identified that account for a major portion of the population variance. Susceptibility of apple fruit to P. expansumis dependent on the ability of the pathogen to produce LysM effectors that actively suppress primary and/or secondary resistance mechanisms in the fruit. Objectives: 1) Identify QTL(s) and molecular markers for blue mold resistance in GMAL4593 mapping population (‘Royal Gala’ X MalussieversiiPI613981), 2) Characterize the transcriptome of the host and pathogen (P. expansum) during the infection process 3) Determine the function of LysM genes in pathogenicity of P. expansum. Methods: A phenotypic evaluation of blue mold resistance in the GMAL4593 mapping population, conducted in several different years, will be used for QTL analysis (using MapQTL 6.0) to identify loci associated with blue mold resistance. Molecular markers will be developed for the resistance loci. Transcriptomic analysis by RNA-seq will be used to conduct a time course study of gene expression in resistant and susceptible apple GMAL4593 genotypes in response to P. expansum, as well as fungal responses to both genotypes. Candidate resistance genes identified in the transcriptomic study and or bioinformatic analysis will be positioned in the ‘Golden Delicious’ genome to identify markers that co-locate with the identified QTL(s). A functional analysis of LysM genes on pathogenicity will be conducted by eliminating or reducing the expression of individual effectors by heterologous recombination and silencing technologies. LysMeffector genes will also be expressed in a yeast expression system to study protein function. Expected Results: Identification of postharvest disease resistance QTLs and tightly-linked genetic markers. Increased knowledge of the role of effectors in blue mold pathogenic