Littérature scientifique sur le sujet « Skin colour-specific transcriptomic traits »

Red pigmentation of the skin is an important consumer trait in peach (Prunus persica). The pigment consists largely of anthocyanin. Here, a transcriptomic contrast, based on RNA-Seq technology, was drawn between a white-skinned (Feitao) and a red-skinned (Qiuxue) peach cultivar. The analysis identified 2407 genes as differentially transcribed in the fruit skin of the two cultivars. Among these were a number of genes known to contribute to anthocyanin synthesis. A quantitative real-time PCR assay was used to validate the RNA-Seq-based estimates of transcript abundance for 14 differentially transcribed genes. Anthocyanin synthesis was observed in the skin of Qiuxue fruit during the late ripening stage, matching the high transcript abundance of the gene encoding UDP glucose: flavonoid 3-O-glucosyltransferase, the final step in the synthesis of anthocyanin.

Fruit skin colour intensity is one of the most important economic traits of purple eggplant. A wide diversity for fruit skin colour intensity exists in purple eggplant and the accumulation of anthocyanins and chlorophylls of fruit skin mainly affected colour intensity. However, limited information is available contributing to the molecular mechanisms underlying fruit skin colour intensity variation in purple eggplant. In the present study, variation of two purple eggplant advanced lines EP26 and EP28, with different fruit skin colour intensity was investigated. Higher anthocyanin contents and lower chlorophyll contents were observed in EP26 with deeper fruit skin colour intensity at two developmental stages. Comparative transcriptome analysis of EP26 and EP28 identified a total of 2218 differential expressed genes (DEGs) at two developmental stages. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that these DEGs were mainly involved in flavonoid biosynthesis and photosynthesis. In addition, a total of 131 transcription factors including MYB, bHLH, WRKY, and NAC exhibited dynamic changes, which might be responsible for the variation of fruit pigments accumulation between EP26 and EP28. Taken together, these results expand our knowledge of molecular mechanisms underlying fruit skin colour intensity variation in eggplant, which allowing for improvement of fruit coloration in eggplant breeding.

Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout prehistory. Functionally naked skin has been the physical interface between the physical environment and the human body for most of the history of the genus Homo , and hence skin coloration has been under intense natural selection. From an original condition of protective, dark, eumelanin-enriched coloration in early tropical-dwelling Homo and Homo sapiens , loss of melanin pigmentation occurred under natural selection as Homo sapiens dispersed into non-tropical latitudes of Africa and Eurasia. Genes responsible for skin, hair and eye coloration appear to have been affected significantly by population bottlenecks in the course of Homo sapiens dispersals. Because specific skin colour phenotypes can be created by different combinations of skin colour–associated genetic markers, loss of genetic variability due to genetic drift appears to have had negligible effects on the highly redundant genetic ‘palette’ for the skin colour. This does not appear to have been the case for hair and eye coloration, however, and these traits appear to have been more strongly influenced by genetic drift and, possibly, sexual selection. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

Abstract Sexual dimorphism often results from hormonally regulated trait differences between the sexes. In sex-role-reversed vertebrates, females often have ornaments used in mating competition that are expected to be under hormonal control. Males of the sex-role-reversed Gulf pipefish (Syngnathus scovelli) develop female-typical traits when they are exposed to estrogens. We aimed to identify genes whose expression levels changed during the development and maintenance of female-specific ornaments. We performed RNA-sequencing on skin and muscle tissue in male Gulf pipefish with and without exposure to estrogen to investigate the transcriptome of the sexually dimorphic ornament of vertical iridescent bands found in females and estrogen-exposed males. We further compared differential gene expression patterns between males and females to generate a list of genes putatively involved in the female secondary sex traits of bands and body depth. A detailed analysis of estrogen-receptor binding sites demonstrates that estrogen-regulated genes tend to have nearby cis-regulatory elements. Our results identified a number of genes that differed between the sexes and confirmed that many of these were estrogen-responsive. These estrogen-regulated genes may be involved in the arrangement of chromatophores for color patterning, as well as in the growth of muscles to achieve the greater body depth typical of females in this species. In addition, anaerobic respiration and adipose tissue could be involved in the rigors of female courtship and mating competition. Overall, this study generates a number of interesting hypotheses regarding the genetic basis of a female ornament in a sex-role-reversed pipefish.

Apricot (Prunus armeniaca L.) is an economically important tree species globally cultivated in temperate areas. Italy has an ample number of traditional varieties, but numerous landraces are abandoned and at risk of extinction because of increasing urbanization, agricultural intensification, and varietal renewal. In this work, we investigated the morphological and genetic diversity present in an ex-situ collection of 28 neglected varieties belonging to the so-called “Vesuvian apricot”. Our aim was to understand the level of diversity and the possible link between the promotion of specific fruit types (e.g., by public policies) and the intraspecific variation in apricot. The combination of five continuous and seven categorical traits allowed us to phenotypically distinguish the varieties; while fruit quality-related attributes displayed high variation, both apricot size and skin colour were more uniform. The twelve fluorescent-based Simple Sequence Repeats (SSRs) markers identified cultivar-specific molecular profiles and revealed a high molecular diversity, which poorly correlated with that described by the morphological analysis. Our results highlighted the complementary information provided by the two sets of descriptors and that DNA markers are necessary to separate morphologically related apricot landraces. The observed morphological and genetic differences suggest a loss of diversity influenced by maintenance breeding of specific pomological traits (e.g., skin colour and size). Finally, our study provided evidence to recommend complementary strategies to avoid the loss of diversity in apricot. Actions should pivot on both the promotion of easily identified premium products and more inclusive biodiversity-centred on-farm strategies.

Background/Aims: Earlobe color is a typical external trait in chicken. There are some previous studies showing that the chicken white/red earlobe color is a polygenic and sex-linked trait in some breeds, but its molecular genetic and histological mechanisms still remain unclear. Methods: We herein utilized histological section, genome-wide association study (GWAS) and RNA-seq, further to investigate the potential histological and molecular genetic mechanisms of white/red earlobe formation in Qiangyuan Partridge chicken (QYP). Results: through histological section analysis, we found the dermal papillary layer of red earlobes had many more blood vessels than that of white earlobes. And we identified a total of 44 SNPs from Chromosome 1, 2, 3, 4, 9, 10, 11, 13, 19, 20, 23 and Z, that was significantly associated with the chicken white/red earlobe color from GWAS, along with 73 significantly associated genes obtained (e.g., PIK3CB, B4GALT1 and TP63), supporting the fact that the white/red earlobe color was also polygenic and sex-linked in QYP. Importantly, PIK3CB and B4GALT1 are both involved in the biological process of angiogenesis, which may directly give rise to the chicken white earlobe formation through regulating blood vessel density in chicken earlobe. Additionally, through contrast of RNA-seq profiles between white earlobe skins and red earlobe skins, we further identified TP63 and CDH1 differentially expressed. Combined with the existing knowledge of TP63 in epithelial development and tumor angiogenesis, we propose that down-regulated TP63 in white earlobes may play roles in thickening the skin and decreasing the vessel numbers in dermal papillary layer, thereby contributing to the white earlobe formation via paling the redness of the skin in QYP, but the specific mechanism remains to be further clarified. Conclusion: our findings advance the existing understanding of the white earlobe formation, as well as provide new clues to understand the molecular mechanism of chicken white/red earlobe color formation.

Abstract. The coat colour of animals is an extremely important trait that affects their behaviour and is decisive for survival in the natural environment. In farm animal breeding, as a result of the selection of a certain coat colour type, animals are characterized by a much greater variety of coat types. This makes them an appropriate model in research in this field. A very important aspect of the coat colour types of farm animals is distinguishing between breeds and varieties based on this trait. Furthermore, for the sheep breeds which are kept for skins and wool, coat/skin colour is an important economic trait. Until now the study of coat colour inheritance in sheep proved the dominance of white colour over pigmented/black coat or skin and of black over brown. Due to the current knowledge of the molecular basis of ovine coat colour inheritance, there is no molecular test to distinguish coat colour types in sheep although some are available for other species, such as cattle, dogs, and horses. Understanding the genetic background of variation in one of the most important phenotypic traits in livestock would help to identify new genes which have a great effect on the coat colour type. Considering that coat colour variation is a crucial trait for discriminating between breeds (including sheep), it is important to broaden our knowledge of the genetic background of pigmentation. The results may be used in the future to determine the genetic pattern of a breed. Until now, identified candidate genes that have a significant impact on colour type in mammals mainly code for factors located in melanocytes. The proposed candidate genes code for the melanocortin 1 receptor (MC1R), agouti signaling protein (ASIP), tyrosinase-related protein 1 (TYRP1), microphthalmia-associated transcription factor MITF, and v-kit Hardy–Zuckerman 4 feline sarcoma viral oncogene homologue (KIT). However, there is still no conclusive evidence of established polymorphisms for specific coat colour types in sheep.

Little is known about the genetic architecture of traits important for salmonid restoration ecology. We mapped quantitative trait loci (QTL) using single nucleotide polymorphisms (SNPs) for juvenile body length, weight, shape, and vertical skin pigmentation patterns (parr marks) within three hybrid backcross families between European and North American subspecies of Atlantic salmon. Amounts of variation in skin colour and pattern quantified in the two second-generation transAtlantic families exceeded the ranges seen in purebred populations. GridQTL analyses using low-density female-specific linkage maps detected QTL showing experiment-wide significance on Ssa02, Ssa03, Ssa09, Ssa11, Ssa19, and Ssa26/28 for both length and weight; on Ssa04 and Ssa23 for parr mark number; on Ssa09 and Ssa13 for parr mark contrast; and on Ssa05, Ssa07, Ssa10, Ssa11, Ssa18, Ssa23, and Ssa26/28 for geometric morphometric shape coordinates. Pleiotrophic QTL on Ssa11 affected length, weight, and shape. No QTL was found that explained more than 10% of the phenotypic variance in pigmentation or shape traits. Each QTL was approximately positioned on the physical map of the Atlantic salmon genome. Some QTL locations confirmed previous studies but many were new. Studies like ours may increase the success of salmon restoration projects by enabling better phenotypic and genetic matching between introduced and extirpated strains.

ABSTRACTThis article reviews the existing evolutionary perspectives on the acute stress response habitual faintness and blood-injection-injury type-specific phobia (BIITS phobia). In this article, an alternative evolutionary perspective, based on recent advances in evolutionary psychology, is proposed. Specifically, that fear–induced faintness (eg, fainting following the sight of a syringe, blood, or following a trivial skin injury) is a distinctHomo sapiens-specific extreme-stress survival response to an inescapable threat. The article suggests that faintness evolved in response to middle paleolithic intra-group and inter-group violence (of con-specifics) rather than as a pan-mammalian defense response, as is presently assumed. Based on recent literature, freeze, flight, fight, fright, faint provides a more complete description of the human acute stress response sequence than current descriptions. Faintness, one of three primary physiological reactions involved in BIITS phobia, is extremely rare in other phobias. Since heritability estimates are higher for faintness than for fears or phobias, the author suggests that trait-faintness may be a useful complement to trait-anxiety as an endophenotype in research on the human fear circuitry. Some implications for the forthcomingDiagnostic and Statistical Manual of Mental Disorders, Fifth Editionas well as for clinical, health services, and transcriptomic research are briefly discussed.

Donkeys, with high economic value for meat, skin and milk production, are important livestock. However, the current insights into reproduction of donkeys are far from enough. To obtain a deeper understanding, the differential expression analysis and weighted gene co-expression network analysis (WGCNA) of transcriptomic data of testicular and epididymis tissues in donkeys were performed. In the result, there were 4313 differentially expressed genes (DEGs) in the two tissues, including 2047 enriched in testicular tissue and 2266 in epididymis tissue. WGCNA identified 1081 hub genes associated with testis development and 6110 genes with epididymal development. Next, the tissue-specific genes were identified with the above two methods, and the gene ontology (GO) analysis revealed that the epididymal-specific genes were associated with gonad development. On the other hand, the testis-specific genes were involved in the formation of sperm flagella, meiosis period, ciliary assembly, ciliary movement, etc. In addition, we found that eca-Mir-711 and eca-Mir-143 likely participated in regulating the development of epididymal tissue. Meanwhile, eca-Mir-429, eca-Mir-761, eca-Mir-200a, eca-Mir-191 and eca-Mir-200b potentially played an important role in regulating the development of testicular tissue. In short, these results will contribute to functional studies of the male reproductive trait in donkeys.

Lo sviluppo della bacca di vite può essere descritto come una successione di cambiamenti fisiologici e biochimici che riflettono la modulazione trascrizionale di molti geni. Nello scorso decennio molti studi trascrittomici sono stati eseguiti per descrivere in modo più approfondito questo processo di sviluppo dinamico e complesso. Tuttavia, la maggior parte di questi studi trascrittomici si sono focalizzati solo su un’unica varietà per volta e quindi vi è ancora una mancanza di risorse per poter effettuare comparazioni sullo sviluppo della bacca in differenti varietà di vite. Questa tesi riguarda la prima comparazione del trascrittoma della bacca di vite effettuato attraverso RNA sequencing di 120 campioni di RNA, corrispondenti alle bacche di dieci varietà raccolte a quattro stadi fenologici, due precedenti e due successivi all’invaiatura, in triplicato biologico. Quest’analisi RNA-seq ha mostrato un’evidente e profonda transizione del trascrittoma dalla fase verde alla maturazione che avviene all’invaiatura indipendentemente da colore della buccia e varietà, che coinvolge la soppressione di diversi processi metabolici relativi alla crescita vegetativa, e l’induzione di solo poche vie, come processi di metabolismo secondario e di risposta a stimoli biotici. Questo importante riprogramma del trascrittoma durante la maturazione è stato evidenziato da diversi approcci: correlazione con distanza di Pearson, analisi a componenti principali (PCA), O2PLS-DA, ricerca di biomarcatori, analisi clustering e network di correlazione. La creazione della prima via trascrittomica di sviluppo della bacca di vite, corrispondente a geni aventi un profilo di espressione simile durante tutto lo sviluppo indipendentemente dalla varietà, ha permesso di identificare geni coinvolti nei maggiori processi biologici che avvengono durante la maturazione del frutto. Infine, l’espressione dei geni appartenenti alla via biosintetica dei fenilpropanoidi/flavonoidi si sono mostrati insufficienti da soli nello spiegare le differenze trascrittomiche tra varietà rosse e bianche; tuttavia si presuppone che questi – probabilmente per effetto dell’accumulo di antociani nella buccia della bacca dall’inizio della maturazione – influenzino comunque il programma della fase di maturazione, determinando il coinvolgimento e reclutamento di geni appartenenti ad altri processi biologici.
Grape berry development can be described as a succession of physiological and biochemical changes reflecting the transcriptional modulation of many genes. In the last decade, many transcriptomic studies have been carried out to deeper describe this dynamic and complex development. Nonetheless, most of those transcriptomic studies focused on one single variety at a time and then there is still a lack of resources for comparing berry development in different grape varieties. This thesis describes the first berry transcriptome comparison carried out by RNA sequencing of 120 RNA samples, corresponding to 10-variety berries collected at four phenological growth stages, two pre- and two post-véraison, in biological triplication. This RNA-Seq analysis showed an evident deep green-to-maturation transcriptome shift occurring at véraison independently on skin colour and variety, which involves the suppression of diverse metabolic processes related to vegetative growth, and the induction of only a few pathways, such as secondary metabolic processes and responses to biotic stimuli. This fundamental transcriptome reprogramming during ripening was highlighted by distinct approaches: Pearson’s correlation distance, PCA, O2PLS-DA, biomarker discovery, clustering analysis and correlation network method. The establishment of the first grape berry development transcriptomic route, corresponding to the genes having similar patterns of expression during whole development independently on the variety, allowed identifying genes involved in the main biological processes occurring during berry development. Finally, the expression of phenylpropanoid/flavonoid biosynthetic pathway-related genes was found to be insufficient by itself to explain the differences between red- and white-grape transcriptomes, however it was supposed to influence – supposedly by the effect of anthocyanins accumulation in berry skin since the onset of ripening – maturation-phase transcriptional program, determining the recruitment of genes belonging to other biological processes.

Pig domestication was initiated some 10,000 years ago. Thus, within a fairly short period of time, from an evolutionary perspective, a remarkable change in phenotype has taken place. Until recently (the last few hundred years), the selection intensity was weak but selection on traits such as behaviour and disease resistance must have occurred early. Docile animals resistant to stress were likely to be kept by the early farmers. Less obviously, coat colour is a trait that also was altered early during domestication. New coat colour variants occur by spontaneous mutations, but in nature there is a strong purifying selection eliminating such mutations because they provide less efficient camouflage or fail to attract mates. In contrast, such mutations have accumulated in domestic animals—why? One reason is of course relaxed purifying selection, but this is not the only reason. A less efficient camouflage of the domestic stock could be advantageous for the farmer and maybe it was used to distinguish improved domestic forms from their wild counterparts. Today, coat colour is often used as a breed-specific marker. For instance, a Large White pig should be white and a Piétrain pig should be spotted. Furthermore, there is strong selection for white colour in some breeds because of consumer demand for pork meat without any pigmented spots in the remaining skin. Charles Darwin was the first to realize that the phenotypic change in domestic animals resulting from selective breeding is an excellent model for phenotypic evolution due to natural selection (Darwin 1859). In fact, he became a pigeon breeder himself and used domestic animals as a proof-of-principle for his revolutionary theory on natural selection as a driving force for evolution. The first chapter of The Origin of Species (Darwin 1859) concerns observations on domestic animals, and nine years later he published two volumes on The Variation of Animals and Plants under Domestication (Darwin 1868). In the latter book he describes the phenotypic changes that have occurred in the pig and other domestic animals as a consequence of domestication. As a result of the development of molecular tools in the form of well-developed genetic maps and large number of genetic markers we are now in position to start unravelling the molecular basis for phenotypic changes in the pig and other domestic animals.