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1
FRANKHAM, RICHARD. « Quantitative genetics in conservation biology ». Genetical Research 74, no 3 (décembre 1999) : 237–44. http://dx.doi.org/10.1017/s001667239900405x.
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Most of the major genetic concerns in conservation biology, including inbreeding depression, loss of evolutionary potential, genetic adaptation to captivity and outbreeding depression, involve quantitative genetics. Small population size leads to inbreeding and loss of genetic diversity and so increases extinction risk. Captive populations of endangered species are managed to maximize the retention of genetic diversity by minimizing kinship, with subsidiary efforts to minimize inbreeding. There is growing evidence that genetic adaptation to captivity is a major issue in the genetic management of captive populations of endangered species as it reduces reproductive fitness when captive populations are reintroduced into the wild. This problem is not currently addressed, but it can be alleviated by deliberately fragmenting captive populations, with occasional exchange of immigrants to avoid excessive inbreeding. The extent and importance of outbreeding depression is a matter of controversy. Currently, an extremely cautious approach is taken to mixing populations. However, this cannot continue if fragmented populations are to be adequately managed to minimize extinctions. Most genetic management recommendations for endangered species arise directly, or indirectly, from quantitative genetic considerations.
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Armstrong, Graeme. « Conservation and the Genetics of Populations ». Pacific Conservation Biology 14, no 2 (2008) : 146. http://dx.doi.org/10.1071/pc080146.
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I am sure many readers have experienced the excruciating situation of being involved in a conservation project that makes no effort to include a genetic component in the methodology. This is often due to a lack of understanding by managers compounded by an inability of biologists to remedy this situation by demonstrating the importance of genetics to the desired conservation outcome. The authors of Conservation and the Genetics of Populations have aimed their text at ?broadly trained biologists? to enable an understanding and application of genetic principles to conservation problems. If successful this would go a long way to alleviating this problem.
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Varvio, Sirkka-Liisa, Ranajit Chakraborty et Masatoshi Nei. « Genetic variation in subdivided populations and conservation genetics ». Heredity 57, no 2 (octobre 1986) : 189–98. http://dx.doi.org/10.1038/hdy.1986.109.
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Benirschke, Kurt. « Conservation and Genetics of Populations ». Journal of Heredity 97, no 6 (1 novembre 2006) : 612–13. http://dx.doi.org/10.1093/jhered/esl039.
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Priyono, Dwi Sendi, Dedy Duryadi Solihin, Achmad Farajallah et Bambang Purwantara. « Genetic Diversity of the Endangered Endemic Anoa (Bubalus spp) : Implication for Conservation ». HAYATI Journal of Biosciences 29, no 5 (17 mai 2022) : 586–96. http://dx.doi.org/10.4308/hjb.29.5.586-596.
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Anoa is an endemic ungulate in Sulawesi and its status now is endangered because the population continues to decline. Conservation genetics is one of the crucial issues in the anoa conservation strategy and action plan 2013-2022 document, but this genetic data is not yet available. To investigate and provide valuable information for conservation genetics measures, thirteen polymorphic microsatellites were used to analyze 20 adult anoa. Anoa has relatively low genetic diversity within populations (HO = 0.58), and high genetic differentiation among populations (FST = 0157). Although the anoa population has a bottleneck signal (T.P.M: 0.019; P0.05), the bottleneck simulation results show that the loss of genetic diversity is being slow over the next 100 years (9.5%). We provide some recommendations for conservation genetics based on the findings in this paper, including monitoring and genetically mapping for other anoa populations due to bottleneck signals, establishing the founder of the ex-situ population by examining their genetic diversity status, maintaining and increasing the number of individuals in the ex-situ population to genetically safe population size, and managing anoa populations by avoiding inbreeding. In-situ and ex-situ conservation programs should be combined to maintain the genetic diversity of anoa.
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Sherwin, WB, et ND Murray. « Population and Conservation Genetics of Marsupials ». Australian Journal of Zoology 37, no 3 (1989) : 161. http://dx.doi.org/10.1071/zo9890161.
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This article summarises current knowledge of marsupial population genetics, and discusses its relevance to the conservation of marsupial species. It has been suggested that there is much lower genetic variation within marsupial populations than in eutherian mammals. This trend is not evident in the electrophoretic data summarised here. However, genetic differentiation between populations, subspecies, and species of marsupials appears to be slightly lower than comparable values for eutherians. Genetic estimates of migration between populations are scarce at present, but show values that are comparable with eutherians. Some studies of marsupial population genetics have used non-electrophoretic characteristics, or have addressed the possibility of selection on the characters analysed. Although few, these studies indicate the suitability of marsupials for such investigations. Recent debate over the theories and applications of conservation genetics has made it clear that more research is required on individual species. Given the record of extinction of marsupials in the last 200 years, it is important to test the applicability of these theories to individual marsupial species. Several examples are discussed emphasising the need for ecological studies that estimate the effective number of reproducing individuals per generation. This figure, called the effective size, is the corner- stone of conservation genetics theory, being an important determinant of both the rate of loss of variation between individuals, and the rate of inbreeding. The effective size of the mainland population of the eastern barred bandicoot, Perameles gunnii, appears to be only about one-tenth of its census number. This result is comparable with estimates made in other vertebrates, and demonstrates that many marsupial species which appear to have an adequate census size on ecological grounds may face genetic problems resulting from small effective size.
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Scribner, Kim T. « Conservation genetics of managed ungulate populations ». Acta Theriologica 38 (20 mai 1993) : 89–101. http://dx.doi.org/10.4098/at.arch.93-44.
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Ouborg, N. Joop. « Integrating population genetics and conservation biology in the era of genomics ». Biology Letters 6, no 1 (2 septembre 2009) : 3–6. http://dx.doi.org/10.1098/rsbl.2009.0590.
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As one of the final activities of the ESF-CONGEN Networking programme, a conference entitled ‘Integrating Population Genetics and Conservation Biology’ was held at Trondheim, Norway, from 23 to 26 May 2009. Conference speakers and poster presenters gave a display of the state-of-the-art developments in the field of conservation genetics. Over the five-year running period of the successful ESF-CONGEN Networking programme, much progress has been made in theoretical approaches, basic research on inbreeding depression and other genetic processes associated with habitat fragmentation and conservation issues, and with applying principles of conservation genetics in the conservation of many species. Future perspectives were also discussed in the conference, and it was concluded that conservation genetics is evolving into conservation genomics, while at the same time basic and applied research on threatened species and populations from a population genetic point of view continues to be emphasized.
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Testroet, Philip, Dietmar Quandt, Arnoldo Santos Guerra, Kai Müller et Wolfram Lobin. « Population genetics and conservation of Sideroxylon canariense (Sapotaceae) on the Canary Islands ». Vieraea Folia scientiarum biologicarum canariensium 41, Vieraea 41 (2013) : 319–32. http://dx.doi.org/10.31939/vieraea.2013.41.21.
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Genetic diversity patterns of different populations were studied in Sideroxylon canariense, a Canary Island endemic of conservation concern. The species range is composed of a number of very small and isolated populations. Genetic variation of these populations was analyzed using: (1) inter simple sequence repeats (ISSR), a common fingerprinting method in plant population genetics, and (2) nucleotide sequence analyses of the nuclear ITS region. While no intraspecific variation was detected among the ITS sequences, the ISSR data showed a very low degree of intraspecific genetic diversity among S. canariense populations on the Canaries, with very few genotypes. We believe that many of the populations consist of a single individual that propagates asexually. Action is urgently required to protect and propagate the highly endangered populations.
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Freeland, Joanna R., Joy Gillespie, Claudia Ciotir et Marcel E. Dorken. « Conservation genetics of Hill’s thistle (Cirsium hillii) ». Botany 88, no 12 (décembre 2010) : 1073–80. http://dx.doi.org/10.1139/b10-080.
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Populations at the edges of their geographical ranges are often characterized by reduced genetic diversity and increased genetic differentiation. These patterns may be exacerbated by specialized associations between plants and uncommon habitats. Together, reduced diversity and increased subdivision may increase the risk of population extirpation, an issue that is particularly important for plants classified as rare or threatened. Hill’s thistle (Cirsium hillii (Canby) Fernald), is a perennial herb endemic to the Great Lakes region and is considered threatened in Canada where its northernmost distribution occurs. We used microsatellite markers to genotype plants from 11 populations of Hill’s thistle that span the range of the species distribution within Canada. These data were used to investigate levels of genetic diversity within populations and genetic differentiation between populations, and to evaluate associations between patterns of genetic variation and those expected under ongoing habitat loss. Genetic differentiation among populations was low, although significant pairwise FST values, along with the presence of private alleles in most populations, was consistent with moderate to low gene flow. Nevertheless, in comparison with a congeneric rare species (Cirsium pitcheri) that occurs in the same geographical region in Canada, genetic diversity within most populations was high, and we suggest that this is at least partially attributable to this species’ combination of sexual and clonal reproduction. Despite high levels of genetic diversity, Hill’s thistle should probably remain a designated species at risk because of ongoing habitat loss; however, our data suggest that Hill’s thistle is unlikely to suffer from reduced genetic diversity in the foreseeable future.
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Piorski, NM, A. Sanches, LF Carvalho-Costa, T. Hatanaka, M. Carrillo-Avila, PD Freitas et PM Galetti Jr. « Contribution of conservation genetics in assessing neotropical freshwater fish biodiversity ». Brazilian Journal of Biology 68, no 4 suppl (novembre 2008) : 1039–50. http://dx.doi.org/10.1590/s1519-69842008000500011.
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Human activities have a considerable impact on hydrographic systems and fish fauna. The present review on conservation genetics of neotropical freshwater fish reveals that DNA analyses have been promoting increased knowledge on the genetic structure of fish species and their response to environmental changes. This knowledge is fundamental to the management of wild fish populations and the establishment of Evolutionary Significant Units capable of conserving genetic integrity. While population structuring can occur even in long-distance migratory fish, isolated populations can show reduced genetic variation and be at greater risk of extinction. Phylogeography and phylogeny have been powerful tools in understanding the evolution of fish populations, species and communities in distinct neotropic environments. Captive fish can be used to introduce new individuals and genes into the wild and their benefits and disadvantages can be monitored through genetic analysis. Understanding how fish biodiversity in neotropical freshwaters is generated and maintained is highly important, as these habitats are transformed by human development and fish communities are increasingly exploited as food sources to sustain a growing human population.
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Watson, Simon. « Conservation of Wildlife Populations : Demography, Genetics and Management ». Pacific Conservation Biology 14, no 2 (2008) : 147. http://dx.doi.org/10.1071/pc080147.
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Effective wildlife management needs to be based on the application of sound scientific principles and concepts. Both of these books provide a framework for the application of concepts and principles to wildlife management problems and attempt to bridge the gap between research and its application in management. Conservation of Wildlife Populations, by L. Scott Mills, explains theories, concepts and principles developed in the field of population biology, and their management applications. It encompasses population ecology, demography and population genetics. Wildlife Damage Control, by Jim Hone, identifies and explains the application of principles involved in assessing and controlling damage caused by wildlife.
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Osborne, WS, et JA Norman. « Conservation Genetics of Corroboree Frogs, Pseudophryne-Corroboree Moore (Anura, Myobatrachidae) - Population Subdivision and Genetic-Divergence ». Australian Journal of Zoology 39, no 3 (1991) : 285. http://dx.doi.org/10.1071/zo9910285.
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Reproductive compatibility and population genetic structure were examined in the corroboree frog, Pseudophryne corroboree, a species restricted to montane and subalpine environments in south-eastern Australia. The species comprises three geographic populations, represented by two morphological forms. Hybridisation experiments showed that the allopatric populations are interfertile, although crosses between the Snowy Mountains population (southern form) and each of the two northern populations (northern form) resulted in a significantly higher number of tadpoles with growth abnormalities. An electrophoretic examination of metamorphlings indicated that there was considerable genetic divergence between the two forms, with several loci approaching fixation of alternate alleles. The Snowy Mountains population also had substantially reduced levels of genetic variation compared to the two northern populations. Although genetic distances generally correlate with geographic distance, the genetic differences between the northern and southern populations form a pronounced step, not explicable by geographic distance alone. These findings have taxonomic implications which should be taken into account when considering the conservation management of this uncommon species.
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Davy, Christina M., et Robert W. Murphy. « Conservation genetics of the endangered Spotted Turtle (Clemmys guttata) illustrate the risks of “bottleneck tests” ». Canadian Journal of Zoology 92, no 2 (février 2014) : 149–62. http://dx.doi.org/10.1139/cjz-2013-0188.
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Studies of population genetics in turtles have suggested that turtles do not experience genetic impacts of bottlenecks as strongly as expected. However, recent studies cast doubt on two commonly used tests implemented in the program BOTTLENECK, suggesting that these findings should be re-evaluated. The Spotted Turtle (Clemmys guttata (Schneider, 1792)) is endangered both globally and within Canada, but genetic data required to develop effective recovery strategies are unavailable. Here, we conducted the first study of population genetic structure in C. guttata. We then used multiple small populations of C. guttata as replicates to test whether the commonly used program BOTTLENECK could detect the genetic signature of bottlenecks in our study populations, which are all thought to have experienced significant declines in the past 2–3 generations (75 years). Turtles (n = 256) were genotyped at 11 microsatellite loci. A suite of Bayesian population genetics analyses and a principal coordinates analysis identified a minimum of 6 distinct genetic populations and a maximum of 10 differentiated subpopulations across the sampled Canadian range of C. guttata, which corresponded to demographically independent units. BOTTLENECK failed to detect population declines. A literature review found that bottleneck tests in 17 of 18 previous genetic studies of tortoises and freshwater turtles were based on suboptimal sampling, potentially confounding their results. High retention of genetic diversity (allelic richness and heterozygosity) in isolated populations of C. guttata and other turtle species is encouraging for species recovery, but conclusions about the prevalence of genetic bottlenecks in such populations should be re-examined.
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Skorupski, Jakub. « Fifty Years of Research on European Mink Mustela lutreola L., 1761 Genetics : Where Are We Now in Studies on One of the Most Endangered Mammals ? » Genes 11, no 11 (11 novembre 2020) : 1332. http://dx.doi.org/10.3390/genes11111332.
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The purpose of this review is to present the current state of knowledge about the genetics of European mink Mustela lutreola L., 1761, which is one of the most endangered mammalian species in the world. This article provides a comprehensive description of the studies undertaken over the last 50 years in terms of cytogenetics, molecular genetics, genomics (including mitogenomics), population genetics of wild populations and captive stocks, phylogenetics, phylogeography, and applied genetics (including identification by genetic methods, molecular ecology, and conservation genetics). An extensive and up-to-date review and critical analysis of the available specialist literature on the topic is provided, with special reference to conservation genetics. Unresolved issues are also described, such as the standard karyotype, systematic position, and whole-genome sequencing, and hotly debated issues are addressed, like the origin of the Southwestern population of the European mink and management approaches of the most distinct populations of the species. Finally, the most urgent directions of future research, based on the research questions arising from completed studies and the implementation of conservation measures to save and restore M. lutreola populations, are outlined. The importance of the popularization of research topics related to European mink genetics among scientists is highlighted.
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Norman, Janette, et Les Christidis. « Genetics and the conservation of Australian birds ». Pacific Conservation Biology 3, no 3 (1997) : 306. http://dx.doi.org/10.1071/pc970306.
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Molecular genetic techniques can be used to address a wide array of contemporary conservation problems encountered in the management of captive and wild bird populations. Most applications pertain to issues relevant to the management of populations or species. These range from sex identification in breeding programmes involving species in which the sexes are phenotypically monomorphic, to the identification of taxonomic diversity at the level of species, subspecies and populations. Additionally, comparative analyses of intra-population variation provide a means of identifying populations more at risk from inbreeding and a loss of diversity. This provides a more tractable approach for the conservation and management of genetic diversity than derived from theoretical considerations about the genetic consequences of small population size. A recent development away from these traditional species-based approaches is the use of information revealed by studies of comparative phylogeography to address issues relevant to the management of entire communities and ecosystems. Molecular studies of non-threatened taxa are also an important tool for wildlife management. Nonthreatened species can be used as indicators of regional biodiversity or to provide information which will assist in the conservation of a closely related species. Molecular studies of apparently widespread and abundant species may also reveal previously unrecognized taxonomic diversity of significance for conservation. With the impressive array of molecular tools now available for addressing issues in conservation biology it is important that they not be applied indiscriminately. Careful consideration needs to be given to the specific needs of wildlife management and the appropriateness of genetic studies should be evaluated on a case by case basis. In some instances molecular studies may not be warranted, providing little information beyond that which has been obtained from ecological and demographic studies or contained in traditional taxonomies.
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Monroy-Vilchis, Octavio, Rosa-Laura Heredia-Bobadilla, Martha M. Zarco-González, Víctor Ávila-Akerberg et Armando Sunny. « Genetic diversity and structure of two endangered mole salamander species of the Trans-Mexican Volcanic Belt ». Herpetozoa 32 (8 octobre 2019) : 237–48. http://dx.doi.org/10.3897/herpetozoa.32.e38023.
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The most important factor leading to amphibian population declines and extinctions is habitat degradation and destruction. To help prevent further extinctions, studies are needed to make appropriate conservation decisions in small and fragmented populations. The goal of this study was to provide data from the population genetics of two micro-endemic mole salamanders from the Trans-Mexican Volcanic Belt. Nine microsatellite markers were used to study the population genetics of 152 individuals from two Ambystoma species. We sampled 38 individuals in two localities for A. altamirani and A. rivualre. We found medium to high levels of genetic diversity expressed as heterozygosity in the populations. However, all the populations presented few alleles per locus and genotypes. We found strong genetic structure between populations for each species. Effective population size was small but similar to that of the studies from other mole salamanders with restricted distributions or with recently fragmented habitats. Despite the medium to high levels of genetic diversity expressed as heterozygosity, we found few alleles, evidence of a genetic bottleneck and that the effective population size is small in all populations. Therefore, this study is important to propose better management plans and conservation efforts for these species.
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Potter, Sally, et Janine E. Deakin. « Cytogenetics : an important inclusion in the conservation genetics toolbox ». Pacific Conservation Biology 24, no 3 (2018) : 280. http://dx.doi.org/10.1071/pc18016.
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Conservation uses information from genetics to assist in management decisions. However, conservation genetics typically assesses genetic diversity at the DNA level but this alone does not address all the risks associated with managing wild and captive populations. DNA is packaged into chromosomes. Differences in the number and morphology of chromosomes between species or even between populations of the same species can have important implications for management programs for threatened species. Cytogenetics, analysis of the higher molecular chromosome structure, can provide invaluable insight for the management of threatened species, where DNA alone could not address all genetic risks and threats to populations. Here we outline the important and valuable role of cytogenetics in conservation, highlighting two case studies based on threatened Australian marsupials: rock-wallabies and the Tasmanian devil. In conclusion, we summarise how cytogenetics should be better linked to conservation genetics and integrated into our management of threatened species, to ensure they have the best platform from which to persist and adapt into the future.
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Chávez-Cortázar, Angélica, Ken Oyama, Maried Ochoa-Zavala, Martín Mata-Rosas, Emily Veltjen, Marie-Stéphanie Samain et Mauricio Quesada. « Conservation genetics of relict tropical species of Magnolia (section Macrophylla) ». Conservation Genetics 22, no 2 (15 février 2021) : 259–73. http://dx.doi.org/10.1007/s10592-021-01334-5.
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AbstractSpecial conservation efforts should be made for relict species, as they usually have small population sizes and restricted distributions, placing them in critical extinction risk. To achieve conservation, information about genetic diversity distribution is needed. Here, using nine nuclear microsatellites, we analyzed 23 populations of five recently described species of Magnolia distributed in Mexico, which were previously assigned to Magnolia dealbata. We aimed to determine the level of genetic diversity and the distribution of genetic variation and proposed conservation measures. Compared to other endemic and relict species, we found a moderate level of genetic diversity in most populations; however, we identified two populations with no genetic variation. Additionally, we found evidence of positive values of inbreeding likely due to geitonogamy. We found a strong population structure, low effective population size, and no evidence of bottlenecks. Patterns of genetic differentiation did not support the morphological distinction of five species, so we hypothesized that the gene pools may instead represent well-differentiated populations of a single species. We argue that the pattern of genetic differentiation is explained by the natural fragmentation of the cloud forests after glaciation events, and the effects of genetic drift in small populations poorly connected by gene flow. Despite the moderate levels of genetic diversity, special attention is needed to guarantee conservation, with emphasis on the populations in the central region of the country as well as the valuable populations identified in the southwestern region.
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Benfer, David, Andrew M. Baker, Tina Ball, Ian Gynther, Heather Janetzki et Susan Fuller. « Conservation genetics of the water mouse, Xeromys myoides Thomas, 1889 ». Australian Journal of Zoology 62, no 5 (2014) : 382. http://dx.doi.org/10.1071/zo14019.
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The water mouse, Xeromys myoides, is currently recognised as a vulnerable species in Australia, inhabiting a small number of distinct and isolated coastal regions of Queensland and the Northern Territory. An examination of the evolutionary history and contemporary influences shaping the genetic structure of this species is required to make informed conservation management decisions. Here, we report the first analysis undertaken on the phylogeography and population genetics of the water mouse across its mainland Australian distribution. Genetic diversity was assessed at two mitochondrial DNA (Cytochrome b, 1000 bp; D-loop, 400 bp) and eight microsatellite DNA loci. Very low genetic diversity was found, indicating that water mice underwent a recent expansion throughout their Australian range and constitute a single evolutionarily significant unit. Microsatellite analyses revealed that the highest genetic diversity was found in the Mackay region of central Queensland; population substructure was also identified, suggesting that local populations may be isolated in this region. Conversely, genetic diversity in the Coomera region of south-east Queensland was very low and the population in this region has experienced a significant genetic bottleneck. These results have significant implications for future management, particularly in terms of augmenting populations through translocations or reintroducing water mice in areas where they have gone extinct.
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Pruett, Christin L., Angela Ricono, Cory Spern et Kevin Winker. « Island life and isolation : The population genetics of Pacific Wrens on the North Pacific Rim ». Condor 119, no 1 (1 février 2017) : 131–42. http://dx.doi.org/10.1650/condor-16-183.1.
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Abstract Conservation of intraspecific variation is a growing focus of conservation biology. Island populations can make up a large portion of the variation of widespread species, as they are often isolated and exhibit differences in phenotype and genetic structure compared with mainland populations. We genotyped 169 Pacific Wrens (Troglodytes pacificus) from 9 locations and 6 subspecies in Alaska, USA, and British Columbia, Canada, to examine the population structure, genetic diversity, and likelihood of genetic rescue of island populations of conservation concern. We found that 25% of genetic variation was partitioned among conservation units delineated by subspecies, suggesting that the present framework of managing subspecies as separate units is warranted. Populations found farthest from possible mainland sources had the lowest genetic diversity. The Attu Island population, subspecies T. p. meligerus, had the lowest genetic diversity and highest genetic divergence of all sampled locations, a signal also found in Attu Island populations of Song Sparrow (Melospiza melodia) and Rock Ptarmigan (Lagopus muta). Currently, populations in western Alaska are unlikely to be connected to populations in mainland locations through dispersal, and thus are unlikely candidates for natural genetic or demographic rescue.
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Teixeira, João C., et Christian D. Huber. « The inflated significance of neutral genetic diversity in conservation genetics ». Proceedings of the National Academy of Sciences 118, no 10 (19 février 2021) : e2015096118. http://dx.doi.org/10.1073/pnas.2015096118.
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The current rate of species extinction is rapidly approaching unprecedented highs, and life on Earth presently faces a sixth mass extinction event driven by anthropogenic activity, climate change, and ecological collapse. The field of conservation genetics aims at preserving species by using their levels of genetic diversity, usually measured as neutral genome-wide diversity, as a barometer for evaluating population health and extinction risk. A fundamental assumption is that higher levels of genetic diversity lead to an increase in fitness and long-term survival of a species. Here, we argue against the perceived importance of neutral genetic diversity for the conservation of wild populations and species. We demonstrate that no simple general relationship exists between neutral genetic diversity and the risk of species extinction. Instead, a better understanding of the properties of functional genetic diversity, demographic history, and ecological relationships is necessary for developing and implementing effective conservation genetic strategies.
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Shapcott, A. « Genetic and Ecological Variation in Atherosperma moschatum and the Implications for Conservation of Its Biodiversity ». Australian Journal of Botany 42, no 6 (1994) : 663. http://dx.doi.org/10.1071/bt9940663.
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Population genetics and ecology of Atherosperma moschatum Labill. (sassafras), a major canopy tree of Australian temperate rainforests, were examined and used to identify priorities and strategies for conservation of its genetic diversity. The genetic diversity among populations was fairly low, but higher than average for long-lived late successional or wind dispersed species (Hamrick and Godt 1989). Genetic distances between populations were correlated with geographic distances and climatic differences. The major genetic differentiation was between the mainland populations and those in Tasmania, with the New South Wales populations being quite genetically distinct. Most genetic variation was found within populations, however, most populations were inbred. This is likely to be due to selfing and spatial genetic substructure resulting from vegetative spread and local dispersal. There was evidence of regeneration in all populations, however no consistent regeneration patterns emerged. Population density was inexplicably correlated with genetic distance. There was as much diversity in all variables (ecological and genetic) measured in small isolated populations as there was in stands within larger assemblages; therefore, population size does not appear to be a major factor affecting viability. Genetic variation was spread throughout the distribution of A. moschatum. Therefore, populations from throughout its range would need to be conserved to retain the genetic diversity within this species.
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Ritland, K., L. D. Meagher, D. G. W. Edwards et Y. A. El-Kassaby. « Isozyme variation and the conservation genetics of Garry oak ». Canadian Journal of Botany 83, no 11 (novembre 2005) : 1478–87. http://dx.doi.org/10.1139/b05-114.
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Garry oak ( Quercus garryana Dougl. ex Hook) has a long north–south distribution along the inland Pacific coast. In British Columbia, it is a keystone species in a unique and endangered “Garry oak meadow” ecosystem. Here, we apply isozyme markers to address issues in the conservation and phylogeography of Garry oak. Among 42 populations and 23 gene loci, gene diversity (expected heterozygosity) averaged 0.17, and number of alleles per locus averaged 1.84. These values are about one-half of those found in other white oak species. Using progeny arrays, we found outcrossing rates in two Vancouver Island populations to average 0.96, with no detectable biparental inbreeding; also inbreeding coefficients of the 42 populations averaged near zero (0.025); thus inbreeding is not a significant concern. Cluster analysis of genetic distances identified two major groups of populations: southern Washington – Oregon and Vancouver Island – Gulf Islands; populations within the island region were particularly homogenous. An isolated mainland British Columbia population near Sumas, British Columbia, perhaps of anthropogenic origin, showed the least genetic variability and greatest genetic distance. Generally, geographically isolated populations were more genetically depauperate, which may place handicaps on their survival, but also more genetically distinct, providing a greater evolutionary legacy to the species.
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Wiese, R. J. « Conservation of Wildlife Populations : Demography, Genetics, and Management ». Journal of Heredity 99, no 4 (28 février 2008) : 441–42. http://dx.doi.org/10.1093/jhered/esn021.
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VRIJENHOEK, R. C., M. E. DOUGLAS et G. K. MEFFE. « Conservation Genetics of Endangered Fish Populations in Arizona ». Science 229, no 4711 (26 juillet 1985) : 400–402. http://dx.doi.org/10.1126/science.229.4711.400.
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Bilska, Katarzyna, et Monika Szczecińska. « Comparison of the effectiveness of ISJ and SSR markers and detection of outlier loci in conservation genetics ofPulsatilla patenspopulations ». PeerJ 4 (2 novembre 2016) : e2504. http://dx.doi.org/10.7717/peerj.2504.
Texte intégralRésumé :
BackgroundResearch into the protection of rare and endangered plant species involves genetic analyses to determine their genetic variation and genetic structure. Various categories of genetic markers are used for this purpose. Microsatellites, also known as simple sequence repeats (SSR), are the most popular category of markers in population genetics research. In most cases, microsatellites account for a large part of the noncoding DNA and exert a neutral effect on the genome. Neutrality is a desirable feature in evaluations of genetic differences between populations, but it does not support analyses of a population’s ability to adapt to a given environment or its evolutionary potential. Despite the numerous advantages of microsatellites, non-neutral markers may supply important information in conservation genetics research. They are used to evaluate adaptation to specific environmental conditions and a population’s adaptive potential. The aim of this study was to compare the level of genetic variation inPulsatilla patenspopulations revealed by neutral SSR markers and putatively adaptive ISJ markers (intron-exon splice junction).MethodsThe experiment was conducted on 14 Polish populations ofP. patensand threeP. patenspopulations from the nearby region of Vitebsk in Belarus. A total of 345 individuals were examined. Analyses were performed with the use of eight SSR primers specific toP. patensand three ISJ primers.ResultsSSR markers revealed a higher level of genetic variation than ISJ markers (He= 0.609,He= 0.145, respectively). An analysis of molecular variance (AMOVA) revealed that, the overall genetic diversity between the analyzed populations defined by parametersFSTand ΦPTfor SSR (20%) and ΦPTfor ISJ (21%) markers was similar. Analysis conducted in theStructureprogram divided analyzed populations into two groups (SSR loci) and three groups (ISJ markers). Mantel test revealed correlations between the geographic distance and genetic diversity of Polish populations ofP. patensfor ISJ markers, but not for SSR markers.ConclusionsThe results of the present study suggest that ISJ markers can complement the analyses based on SSRs. However, neutral and adaptive markers should not be alternatively applied. Neutral microsatellite markers cannot depict the full range of genetic variation in a population because they do not enable to analyze functional variation. Although ISJ markers are less polymorphic, they can contribute to the reliability of analyses based on SSRs.
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Marchán, Daniel F., et Jorge Domínguez. « Evaluating the Conservation Status of a North-Western Iberian Earthworm (Compostelandrilus cyaneus) with Insight into Its Genetic Diversity and Ecological Preferences ». Genes 13, no 2 (11 février 2022) : 337. http://dx.doi.org/10.3390/genes13020337.
Texte intégralRésumé :
In spite of the high conservation value of soil fauna, the evaluation of their conservation status has usually been neglected. This is more evident for earthworms, one of the most important ecosystem service providers in temperate habitats but rarely the subject of conservation research. These studies have not been developed in Western Europe, which comprises high diversity and several early-branching, relic genera. One potentially menaced representative of this fauna is Compostelandrilus cyaneus; this risk can be assessed by implementing potential distribution modeling and genetic diversity monitoring to their known populations. Genetic barcoding was performed in representatives of four populations (three of them newly sampled) in order to estimate genetic diversity and population genetics parameters. Ensemble species distribution models were built by combining several algorithms and using the five more relevant bioclimatic and soil variables as predictors. A large amount of genetic diversity was found in a small area of less than 20 km2, with populations located in less managed, better-preserved habitats showing higher genetic variability than populations isolated from natural habitats and surrounded by anthropic habitats. Potential distribution appears to be strongly restricted at a regional scale, and suitable habitats within the extent of occurrence appear fragmented and relatively limited. In addition, the main variables determining the ecological niche of C. cyaneus suggests a vulnerability to climate change and increasing soil compaction. Based on this knowledge, this species was assessed as Critically Endangered following the IUCN Red List of Threatened Species criteria, and some potential conservation actions are suggested.
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Ross-Davis, Amy, Michael Ostry et Keith E. Woeste. « Genetic diversity of butternut (Juglans cinerea) and implications for conservation ». Canadian Journal of Forest Research 38, no 4 (avril 2008) : 899–907. http://dx.doi.org/10.1139/x08-030.
Texte intégralRésumé :
The management of threatened and endangered species can be improved by understanding their patterns of genetic diversity and structure. This paper presents the results of the first analysis of the population genetics of butternut ( Juglans cinerea L.) using nuclear microsatellites. Butternut once was an economically and ecologically valuable hardwood, but now its numbers are rapidly decreasing throughout its native range in eastern North America. By genotyping butternut trees (n = 157) from five populations at seven highly polymorphic loci, we determined that the remaining genetic diversity for the species is considerably higher than previously estimated (mean HE = 0.75). Populations were nearly genetically homogenous (FST = 0.025), with no evidence of isolation by distance. These results indicate that butternut retains a large amount of genetic diversity, and that it is not too late to implement strategies to conserve local butternut populations.
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López-Pujol, J., F. M. Zhang et S. Ge. « Population genetics and conservation of the critically endangered Clematis acerifolia (Ranunculaceae) ». Canadian Journal of Botany 83, no 10 (octobre 2005) : 1248–56. http://dx.doi.org/10.1139/b05-097.
Texte intégralRésumé :
Allozyme electrophoresis was used to evaluate the levels of genetic diversity and population genetic structure of the critically endangered Clematis acerifolia Maximowicz (Ranunculaceae), a narrow endemic species in China. On the basis of variation at 19 putative loci in nine populations covering the entire distribution of this species, low values of genetic diversity were detected (P = 20.5%, A = 1.27, and He = 0.072). A significant deficiency of heterozygotes was found in all populations. Most loci showed deviations from the Hardy–Weinberg equilibrium, probably as a result of population genetic structuring. The high genetic divergence among populations (FST = 0.273) can be interpreted as an effect of the extinction of local populations and genetic drift within extant populations, and has probably been enhanced by habitat fragmentation in recent decades. Threats to this species are mainly anthropogenic (road works, construction of holiday resorts, and extraction activities), although stochastic risks cannot be ignored. Therefore, to preserve extant genetic variation of C. acerifolia, in situ strategies, such as the preservation of its habitat or at least the most diverse populations, and ex situ measures, such as the collection and long-term storage of seeds, should be adopted.
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Rick, Kate, Kym Ottewell, Cheryl Lohr, Rujiporn Thavornkanlapachai, Margaret Byrne et W. Jason Kennington. « Population Genomics of Bettongia lesueur : Admixing Increases Genetic Diversity with no Evidence of Outbreeding Depression ». Genes 10, no 11 (28 octobre 2019) : 851. http://dx.doi.org/10.3390/genes10110851.
Texte intégralRésumé :
Small and isolated populations are subject to the loss of genetic variation as a consequence of inbreeding and genetic drift, which in turn, can affect the fitness and long-term viability of populations. Translocations can be used as an effective conservation tool to combat this loss of genetic diversity through establishing new populations of threatened species, and to increase total population size. Releasing animals from multiple genetically diverged sources is one method to optimize genetic diversity in translocated populations. However, admixture as a conservation tool is rarely utilized due to the risks of outbreeding depression. Using high-resolution genomic markers through double-digest restriction site-associated sequencing (ddRAD-seq) and life history data collected over nine years of monitoring, this study investigates the genetic and fitness consequences of admixing two genetically-distinct subspecies of Bettongia lesueur in a conservation translocation. Using single nucleotide polymorphisms (SNPs) identified from 215 individuals from multiple generations, we found an almost 2-fold increase in genetic diversity in the admixed translocation population compared to the founder populations, and this was maintained over time. Furthermore, hybrid class did not significantly impact on survivorship or the recruitment rate and therefore we found no indication of outbreeding depression. This study demonstrates the beneficial application of mixing multiple source populations in the conservation of threatened species for minimizing inbreeding and enhancing adaptive potential and overall fitness.
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Brown, A. H. D., et C. L. Brubaker. « Genetics and the conservation and use of Australian wild relatives of crops ». Australian Journal of Botany 48, no 3 (2000) : 297. http://dx.doi.org/10.1071/bt98079.
Texte intégralRésumé :
Genetical research stands to make crucial contributions to the in situ conservation of wild Australian relatives of crop plants, management of their ex situ germplasm collections, and their use in crop improvement. For instance, population genetic theory is basic in formulating collecting strategies. Results from the neutral allele model indicate that allelic richness in samples from equilibrium populations is, although directly proportional to the population size, proportional to the logarithm of the sample size. Such trends underline the importance of dividing the sampling effort among many populations. Our empirical genetical studies have been in the Australian wild relatives of soybean and cotton. These species not only contain significant genetic resources for improving their related crops, but also may be at risk from unwanted hybridisation. In perennial Glycine species, previous cytological and genetic research detected major races within the G. tabacina polyploid complex. A maternal phylogeny on the basis of chloroplast restriction-site variation defined plastome lineages and clarified the evolution of the polyploid complexes. Ongoing research with nuclear sequences focuses on the relationship between chloroplast and nuclear phylogenies and morphology. In Gossypium, estimates of interspecific hybrid fertility and outcrossing rates in natural populations near current cotton crops point to negligible risk of transgene escape from genetically engineered commercial cotton cultivars.
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Kunde, Miriam N., Renata F. Martins, Joe Premier, Joerns Fickel et Daniel W. Förster. « Population and landscape genetic analysis of the Malayan sun bear Helarctos malayanus ». Conservation Genetics 21, no 1 (21 novembre 2019) : 123–35. http://dx.doi.org/10.1007/s10592-019-01233-w.
Texte intégralRésumé :
AbstractConservation genetics can provide data needed by conservation practitioners for their decisions regarding the management of vulnerable or endangered species, such as the sun bear Helarctos malayanus. Throughout its range, the sun bear is threatened by loss and fragmentation of its habitat and the illegal trade of both live bears and bear parts. Sharply declining population numbers and population sizes, and a lack of natural dispersal between populations all threaten the genetic diversity of the remaining populations of this species. In this first population genetics study of sun bears using microsatellite markers, we analyzed 68 sun bear samples from Cambodia to investigate population structure and genetic diversity. We found evidence for two genetically distinct populations in the West and East of Cambodia. Ongoing or recent gene flow between these populations does not appear sufficient to alleviate loss of diversity in these populations, one of which (West Cambodia) is characterized by significant inbreeding. We were able to assign 85% of sun bears of unknown origin to one of the two populations with high confidence (assignment probability ≥ 85%), providing valuable information for future bear reintroduction programs. Further, our results suggest that developed land (mostly agricultural mosaics) acts as a barrier to gene flow for sun bears in Cambodia. We highlight that regional sun bear conservation action plans should consider promoting population connectivity and enforcing wildlife protection of this threatened species.
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Gauthier, Martha, Emily Crowe, Lindsey Hawke, Neil Emery, Paul Wilson et Joanna Freeland. « Conservation genetics of Pitcher’s thistle (Cirsium pitcheri), an endangered Great Lakes endemic ». Botany 88, no 3 (mars 2010) : 250–57. http://dx.doi.org/10.1139/b10-006.
Texte intégralRésumé :
Pitcher's thistle ( Cirsium pitcheri Torr. ex Eaton (Torr. & Gray)) is a Great Lakes endemic that in Canada is designated as threatened at both the provincial (Ontario) and national levels. Management plans will benefit from conservation genetic data, which can provide insight into population genetic diversity and differentiation. We obtained genetic data from nuclear and chloroplast microsatellite markers from 17 populations of C. pitcheri around the Great Lakes. The nuclear data revealed overall low levels of diversity, high levels of inbreeding, and low levels of population connectivity. The chloroplast data identified a single haplotype, which is consistent with reduced genetic diversity following postglacial colonization. The high levels of inbreeding within populations will likely pose a serious threat to populations in the short term; these have resulted from a combination of low connectivity between populations, and small and fluctuating population sizes. Future management of C. pitcheri populations should consider human-mediated dispersal of plants or seeds among sites.
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Peñas, Julio, Sara Barrios, Javier Bobo-Pinilla, Juan Lorite et M. Montserrat Martínez-Ortega. « Designing conservation strategies to preserve the genetic diversity ofAstragalus edulisBunge, an endangered species from western Mediterranean region ». PeerJ 4 (18 janvier 2016) : e1474. http://dx.doi.org/10.7717/peerj.1474.
Texte intégralRésumé :
Astragalus edulis(Fabaceae) is an endangered annual species from the western Mediterranean region that colonized the SE Iberian Peninsula, NE and SW Morocco, and the easternmost Macaronesian islands (Lanzarote and Fuerteventura). Although in Spain some conservation measures have been adopted, it is still necessary to develop an appropriate management plan to preserve genetic diversity across the entire distribution area of the species. Our main objective was to use population genetics as well as ecological and phylogeographic data to select Relevant Genetic Units for Conservation (RGUCs) as the first step in designing conservation plans forA. edulis. We identified six RGUCs for in situ conservation, based on estimations of population genetic structure and probabilities of loss of rare alleles. Additionally, further population parameters, i.e. occupation area, population size, vulnerability, legal status of the population areas, and the historical haplotype distribution, were considered in order to establish which populations deserve conservation priority. Three populations from the Iberian Peninsula, two from Morocco, and one from the Canary Islands represent the total genetic diversity of the species and the rarest allelic variation. Ex situ conservation is recommended to complement the preservation ofA. edulis, given that effective in situ population protection is not feasible in all cases. The consideration of complementary phylogeographic and ecological data is useful for management efforts to preserve the evolutionary potential of the species.
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Hassan Mansour. « Population genetics of Hyphaene thebaica Mart., in Rabigh province, Saudi Arabia : Implications for conservation ». GSC Biological and Pharmaceutical Sciences 17, no 3 (30 décembre 2021) : 153–59. http://dx.doi.org/10.30574/gscbps.2021.17.3.0366.
Texte intégralRésumé :
Hyphaene thebaica is a perennial plant distributed in desert and subtropical regions of the world. In Rabigh Province, western Saudi Arabia, the few persisting populations of this species are exposed to many threats, including overcutting and, recently, human habitation. These threats are predicted to be exacerbated with the advancement of aridification caused by climate change. The conservation and revival of the diminished populations of H. thebaica requires an assessment of their genetic diversity and genetic differentiation. To accomplish this objective, we applied 10 simple sequence repeat (SSR) primer pairs, with which all are polymorphic loci. These polymorphic loci were used to determine the population genetics of 60 plant accessions sampled from 5 populations of H. thebaica located in five sites in Rabigh Province: Wadi EL Khaneg, Wadi Al Johfa, Wadi Al Hakak and Wadi Khurieba and Wadi Kuliayah . Low to moderate levels of genetic diversity were found in all populations (the values of the PPL% ranged between 52.5% and 22.5%) along with a decreased value of HT (0.388) and a considerable inbreeding value (F= 0.4552), which verified an obvious shortage of heterozygotes. High genetic differentiation among the populations and a low level of gene flow suggest isolation among the H. thebaica populations, which caused a severe deficiency in gene migration. The data obtained herein will inspire several recommendations for conservation the existing populations, including seed preservation, and management of human activities. All of these actions are urgently needed to prevent imminent extinction.
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Li, Di Yan, Yong Fang Yao, Xiao Feng Huang, An Chun Cheng, Huai Liang Xu, Qing Yong Ni, Qing Zhu et al. « Simple Sequence Repeat (SSR) Polymorphisms and Population Genetics in Sichuan Wild Rhesus Macaques ». Advanced Materials Research 343-344 (septembre 2011) : 690–97. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.690.
Texte intégralRésumé :
Cross-species amplification of twenty-five SSR loci from the DNA of five rhesus macaques of diverse regional origins was conducted using human primers for the polymerase chain reaction (PCR). Seven of these primer pairs, which consistently and unambiguously amplified polymorphic fragments from these five samples, were also used to amplify SSR loci for 111 Sichuan wild rhesus macaques of five different populations. The analysed microsatellite markers produced 109 alleles, varied from 4 to 16 alleles each locus. The number of alleles per population ranged from 6.79 to 11.38. Polymorphic information content showed that all seven loci were highly informative (mean = 0.9017±0.0166, >0.5). The average observed heterozygosity was less than the expected (mean = 0.6795 and mean = 0.8559, respectively). Genetic differentiation among the populations was considerably low with the overall and pairwise FST values (mean = 0.0375), and showed fairly low level of inbreeding (indicated by a mean FIS value of 0. 0.1991). Maintaining genetic diversity is a major issue in conservation biology. In comparison to other captive Macaca mulatta studies, these wild rhesus macaque populations showed a relatively high level of genetic diversity, and there was low gene flow among these populations. Careful genetic management is important for maintaining genetic variability levels. None of the seven informative loci are linked which screened in this study can be applied in future studies on population and conservation genetics of natural primate populations.
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Martínez-León, Tania, Ricardo Clark-Tapia, Jorge E. Campos, Luz Isela Peinado-Guevara, Samuel Campista-León, Francisco Molina-Freaner, Nelly Pacheco-Cruz, Gabriel González-Adame, Juan José Von Thaden Ugalde et Cecilia Alfonso-Corrado. « A Change in Conservation Status of Pachyphytum caesium (Crassulaceae), a Threatened Species from Central Mexico Based on Genetic Studies ». Biology 11, no 3 (27 février 2022) : 379. http://dx.doi.org/10.3390/biology11030379.
Texte intégralRésumé :
Genetic studies in rare species are important to determine their patterns of genetic diversity among populations and implement conservation plans aimed to reduce extinction risks. Pachyphytum caesium is an endemic species with extremely small populations in central Mexico. This work analyzes the diversity and genetic structure of Pachyphytum cesium (Crassulaceae) to change the conservation status and propose conservation strategies. Twelve dominant ISSR markers were used to describe the genetic diversity of all known populations. Additionally, we carried out two simulations to explore how the loss of individuals or the local populations extinction affect the genetics parameters of the species. The average results indicated moderate levels of genetic diversity (number of alleles = 89.7 ± 3.9, expected heterozygosity = 0.212 ± 0.0, and percentage of polymorphic loci = 56.1 ± 3.9), parameters that decreased significantly when simulations were performed in P. caesium. Additionally, a genetic structure of the populations was found with low gene flow (Nm = 0.92). Genetic parameters are negatively affected by the loss of individuals and the local extinction of populations. Based on our results, we propose to reclassify the conservation status of the species in danger of extinction, hence a series of conservation strategies are provided to prevent its disappearance.
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Mosseler, A. « Life history and genetic diversity in red pine : implications for gene conservation in forestry ». Forestry Chronicle 68, no 6 (1 décembre 1992) : 701–8. http://dx.doi.org/10.5558/tfc68701-6.
Texte intégralRésumé :
Red pine, Pinus resinosa Ait., is a suffusively rare species throughout its geographical range, occurring as small, highly fragmented populations. Such species are particularly vulnerable to the genetic and demographic stochasticity that can lead to local extinction and losses of genetic variation. Red pine illustrates the difficulty that species with long generation times have in recovering genetic diversity once it has been lost. Tree species that lose their genetic diversity may not recover the genetic variation required for effective adaptive responses to environmental challenges. Population declines in rare tree species should be viewed with greater concern by forest managers because the loss of a tree species threatens ecological stability and future economic potential in areas of limited biodiversity. Newfoundland's red pine population provides an example for a broader discussion of concepts in population ecology and genetics useful in developing gene conservation efforts for tree populations characterized by fragmented distributions, small population sizes, and declining population numbers. Key words: population ecology, genetic diversity, gene conservation, metapopulation, reproductive success
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Adams, Clare I. M., Michael Knapp, Neil J. Gemmell, Gert-Jan Jeunen, Michael Bunce, Miles D. Lamare et Helen R. Taylor. « Beyond Biodiversity : Can Environmental DNA (eDNA) Cut It as a Population Genetics Tool ? » Genes 10, no 3 (1 mars 2019) : 192. http://dx.doi.org/10.3390/genes10030192.
Texte intégralRésumé :
Population genetic data underpin many studies of behavioral, ecological, and evolutionary processes in wild populations and contribute to effective conservation management. However, collecting genetic samples can be challenging when working with endangered, invasive, or cryptic species. Environmental DNA (eDNA) offers a way to sample genetic material non-invasively without requiring visual observation. While eDNA has been trialed extensively as a biodiversity and biosecurity monitoring tool with a strong taxonomic focus, it has yet to be fully explored as a means for obtaining population genetic information. Here, we review current research that employs eDNA approaches for the study of populations. We outline challenges facing eDNA-based population genetic methodologies, and suggest avenues of research for future developments. We advocate that with further optimizations, this emergent field holds great potential as part of the population genetics toolkit.
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Tessier, Nathalie, Sébastien Rioux Paquette et François-Joseph Lapointe. « Conservation genetics of the wood turtle (Glyptemys insculpta) in Quebec, Canada ». Canadian Journal of Zoology 83, no 6 (1 juin 2005) : 765–72. http://dx.doi.org/10.1139/z05-065.
Texte intégralRésumé :
Throughout its range, the long-term persistence of the wood turtle (Glyptemys insculpta Le Conte, 1830) is jeopardized by habitat perturbations and commercial collection. The main objective of this study was to acquire knowledge on the genetic structure of wood turtle populations within Quebec, where the species reaches the northernmost limit of its range, to identify proper conservation units. The six known populations in Quebec were genetically characterized using five microsatellite loci. Genetic analyses revealed high variability among all populations (HO ranging from 0.561 to 0.886), suggesting that past population declines have not yet affected their genetic diversity. Since populations are located on both shores of the St. Lawrence River, two colonization hypotheses were tested to determine whether the River acted as a dispersal route or as a barrier. Results of AMOVA tests, phylogenetic analyses, and assignment tests demonstrated the clear distinction between populations from both shores, and three genetically different units were identified: the two populations on the north shore and a single homogenous group on the south shore.
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Hart, Steven N., Francis E. Durbian, Casey B. Dillman et Todd T. Eckdahl. « Assessment of Allelic Variation Among Massasauga Rattlesnake Populations via Microsatellite Analysis ». Transactions of the Missouri Academy of Science 42, no 2008 (1 janvier 2008) : 30–38. http://dx.doi.org/10.30956/0544-540x-42.2008.30.
Texte intégralRésumé :
The decline in populations of the eastern massasauga rattlesnake (Sistrurus catenatus catenatus) across its range is of concern to conservation managers and the species is currently a candidate for federal listing. Because only four eastern massasauga populations are known to occur in Missouri, the species is on the Missouri Endangered Species List. We sought to produce a molecular genetic data set that could be used to inform conservation management decisions about three of these populations. Our method was to collect and analyze data from three microsatellites sites in an effort to provide insight into the genetic health of the populations and into relationships between them. Our method was controlled by inclusion of two populations of the western massasauga (Sistrurus catenatus tergeminus) from southeastern Nebraska. The final data set included 111 individuals from Missouri and Nebraska populations. Although a significant portion (92%) of alleles were shared between each population, low levels of heterozygosity were detected, indicating local inbreeding. Tests of population differentiation suggested that little to no gene flow between these populations has occurred, giving rise to unique allele frequencies and combinations which may be of high conservation value. Most notably, significant differentiation was observed between putative subpopulations at the Squaw Creek National Wildlife Refuge that are in close proximity to one another. Our results illustrate the value of molecular genetics analysis in conservation management and have important implications for the management of Missouri massasauga populations.
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Toro, M. A., et A. Caballero. « Characterization and conservation of genetic diversity in subdivided populations ». Philosophical Transactions of the Royal Society B : Biological Sciences 360, no 1459 (7 juillet 2005) : 1367–78. http://dx.doi.org/10.1098/rstb.2005.1680.
Texte intégralRésumé :
We review the available tools for analysing genetic diversity in conservation programmes of subdivided populations. Ways for establishing conservation priorities have been developed in the context of livestock populations, both from the classical population genetic analysis and from the more recent Weitzman's approach. We discuss different reasons to emphasize either within or between-population variation in conservation decisions and the methodology to establish some compromise. The comparison between neutral and quantitative variation is reviewed from both theoretical and empirical points of view, and the different procedures for the dynamic management of conserved subdivided populations are discussed.
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Camadro, E. L., et P. Rimieri. « Ex situ PLANT GERMPLASM CONSERVATION REVISED AT THE LIGHT OF MECHANISMS AND METHODS OF GENETICS ». Journal of Basic and Applied Genetics 32, Issue 1 (juillet 2021) : 11–24. http://dx.doi.org/10.35407/bag.2021.32.01.02.
Texte intégralRésumé :
Plant genetic resources for food and agriculture are ex situ conserved in germplasm banks as samples (accessions) of natural or naturalized populations, either as the originally sampled propagules (mainly seeds) or their multiplications. The premises underlying ex situ conservation are that (a) it is the safest and cheapest alternative for germplasm preservation for future generations and (b) accessions are representative of the genetic diversity encountered in nature. In the past decades, ideas, alternatives and considerations have been put forward on the topic, and protocols have been devised for plant germplasm sampling, conservation and multiplication. However, limitations in the management efficiency of germplasm banks have been pointed out by international organizations. In our opinion, germplasm banks in general need to revise their functioning and management at the light of principles and methods of Genetics. To that end, it is necessary to consider the reproductive biology of higher plants -whose genetic consequences at both the individual plant and the population levels are not always either fully understood or taken into account in devising the protocols-, the genetic structures of wild and cultivated populations, and the course of the genetic material in the populations. In this paper, we discuss the three topics and provide an example of a national forage breeding program, from germplasm bank accessions as the germplasm of origin to the obtainment of commercial cultivars. Finally, we present a proposal as a base for discussion among curators, researchers and breeders. Key words: accessions, breeding, genetic resources, germplasm banks, population genetics
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Camadro, E. L., et P. Rimieri. « Ex situ PLANT GERMPLASM CONSERVATION REVISED AT THE LIGHT OF MECHANISMS AND METHODS OF GENETICS ». Journal of Basic and Applied Genetics 32, Issue 1 (juillet 2021) : 11–24. http://dx.doi.org/10.35407/bag.2020.32.01.02.
Texte intégralRésumé :
Plant genetic resources for food and agriculture are ex situ conserved in germplasm banks as samples (accessions) of natural or naturalized populations, either as the originally sampled propagules (mainly seeds) or their multiplications. The premises underlying ex situ conservation are that (a) it is the safest and cheapest alternative for germplasm preservation for future generations and (b) accessions are representative of the genetic diversity encountered in nature. In the past decades, ideas, alternatives and considerations have been put forward on the topic, and protocols have been devised for plant germplasm sampling, conservation and multiplication. However, limitations in the management efficiency of germplasm banks have been pointed out by international organizations. In our opinion, germplasm banks in general need to revise their functioning and management at the light of principles and methods of Genetics. To that end, it is necessary to consider the reproductive biology of higher plants -whose genetic consequences at both the individual plant and the population levels are not always either fully understood or taken into account in devising the protocols-, the genetic structures of wild and cultivated populations, and the course of the genetic material in the populations. In this paper, we discuss the three topics and provide an example of a national forage breeding program, from germplasm bank accessions as the germplasm of origin to the obtainment of commercial cultivars. Finally, we present a proposal as a base for discussion among curators, researchers and breeders. Key words: accessions, breeding, genetic resources, germplasm banks, population genetics
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Dal Vesco, Lirio L., Valdir M. Stefenon, Leocir J. Welter, Neusa Steiner et Miguel P. Guerra. « Conservation of Billbergia zebrina genetic resources : AFLP polymorphism of in vitro regenerated genotypes ». Plant Genetic Resources 10, no 1 (12 décembre 2011) : 20–23. http://dx.doi.org/10.1017/s1479262111000918.
Texte intégralRésumé :
Biotechnological techniques comprise useful tools for the conservation of endangered plant genetic resources. In the present work, polymorphism and usefulness of amplified fragment length polymorphism (AFLP) markers in assessing the genetic diversity in populations of Billbergia zebrina were investigated in nodular cultures and adult plants of the species. AFLP markers revealed moderate-to-high genetic diversity based on the estimations of Nei's gene diversity (mean He = 0.28), Shannon index of diversity (mean HS = 0.48) and the number of polymorphic fragments (mean of 56.17 polymorphic fragments over six primer pairs). In comparison to published studies of population genetics performed in other bromeliad species, the present study suggests that natural populations of B. zebrina likely maintain high levels of genetic diversity, an important feature towards conservation of plant genetic resources. The results obtained reveal that AFLP markers comprise a powerful tool in order to assess the levels of genetic diversity in natural populations of this endangered species. Integrating AFLP markers with in vitro propagation techniques is understood as an adequate strategy for conservation programmes of this species.
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von Takach, Brenton, Cara E. Penton, Brett P. Murphy, Ian J. Radford, Hugh F. Davies, Brydie M. Hill et Sam C. Banks. « Population genomics and conservation management of a declining tropical rodent ». Heredity 126, no 5 (4 mars 2021) : 763–75. http://dx.doi.org/10.1038/s41437-021-00418-9.
Texte intégralRésumé :
AbstractConservation management is improved by incorporating information about the spatial distribution of population genetic diversity into planning strategies. Northern Australia is the location of some of the world’s most severe ongoing declines of endemic mammal species, yet we have little genetic information from this regional mammal assemblage to inform a genetic perspective on conservation assessment and planning. We used next-generation sequencing data from remnant populations of the threatened brush-tailed rabbit-rat (Conilurus penicillatus) to compare patterns of genomic diversity and differentiation across the landscape and investigate standardised hierarchical genomic diversity metrics to better understand brush-tailed rabbit-rat population genomic structure. We found strong population structuring, with high levels of differentiation between populations (FST = 0.21–0.78). Two distinct genomic lineages between the Tiwi Islands and mainland are also present. Prioritisation analysis showed that one population in both lineages would need to be conserved to retain at least ~80% of alleles for the species. Analysis of standardised genomic diversity metrics showed that approximately half of the total diversity occurs among lineages (δ = 0.091 from grand total γ = 0.184). We suggest that a focus on conserving remnant island populations may not be appropriate for the preservation of species-level genomic diversity and adaptive potential, as these populations represent a small component of the total diversity and a narrow subset of the environmental conditions in which the species occurs. We also highlight the importance of considering both genomic and ecological differentiation between source and receiving populations when considering translocations for conservation purposes.
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Shapcott, A. « Taxonomy, genetics and conservation : a preliminary study of the variation in Actephila lindleyi (Euphorbiaceae) a rainforest shrub ». Pacific Conservation Biology 4, no 2 (1998) : 105. http://dx.doi.org/10.1071/pc980105.
Texte intégralRésumé :
Actephila lindleyi is a highly morphologically variable species. It occurs in disjunct populations in rainforests from Cape York to central New South Wales. Preliminary tests have shown variation between populations is matched by genetic variation at the enzyme and chromosome levels. Thus, taxonomic revision of this species should take this into account. Such taxonomic decisions have implications for conservation and management. For example, the overall conservation status of a widespread species with endangered populations might be much lower than the conservation status of each population when elevated to species status.
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Finkeldey, Reiner. « Forschung zur Vielfalt, vielfältige Forschung : Ziele und Wege der Forstgenetik | Research on diversity, diverse research : objectives and approaches in forest genetics ». Schweizerische Zeitschrift fur Forstwesen 152, no 5 (1 mai 2001) : 162–68. http://dx.doi.org/10.3188/szf.2001.0162.
Texte intégralRésumé :
The genetic information about forest trees is not only of crucial importance for the yield of forestry production systems,but also for determining the evolutionary adaptive potential of tree populations. Thus, the stability of forest ecosystems depends on the sustainable management of forest genetic resources. In this context, tree breeding and conservation of forest genetic resources are mentioned as main applications of research in forest genetics. Genetic inventories are conducted in order to observe the spatial distribution of genetic information at gene marker loci. Such studies allow us to elucidate the evolutionary history of populations and, thus, to draw conclusions about their evolutionary adaptability. Results of a genetic inventory of oak (Quercus spp.) populations native to Switzerland are presented, and their significance for the characterization of genetic systems and adaptive potential is discussed. Future research into forest genetics should aim at improving our understanding of the relationship between variation at biochemical and molecular marker loci and adaptive processes in forest tree populations. The temporal dynamics of genetic structures of forest tree populations as a consequence of anthropogenic environmental change is another important topic of forest genetics in particular for the conservation of rare species.
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Nadeem, Muhammad Azhar, Stalin Juan Vasquez Guizado, Muhammad Qasim Shahid, Muhammad Amjad Nawaz, Ephrem Habyarimana, Sezai Ercişli, Fawad Ali et al. « In-Depth Genetic Diversity and Population Structure of Endangered Peruvian Amazon Rosewood Germplasm Using Genotyping by Sequencing (GBS) Technology ». Forests 12, no 2 (8 février 2021) : 197. http://dx.doi.org/10.3390/f12020197.
Texte intégralRésumé :
Research studies on conservative genetics of endangered plants are very important to establish the management plans for the conservation of biodiversity. Rosewood is an evergreen tree of the Amazon region and its essential oil has great acceptance in the medical and cosmetic industry. The present study aimed to explore the genetic diversity and population structure of 90 rosewood accessions collected from eight localities of Peruvian Amazon territory through DArTseq markers. A total of 7485 informative markers resulted from genotyping by sequencing (GBS) analysis were used for the molecular characterization of rosewood germplasm. Mean values of various calculated diversity parameters like observed number of alleles (1.962), the effective number of alleles (1.669), unbiased expected heterozygosity (0.411), and percent polymorphism (93.51%) over the entire germplasm showed the existence of a good level of genetic variations. Our results showed that the Mairiricay population was more diverse compared to the rest of the populations. Tamshiyacu-2 and Mairiricay-15 accessions were found genetically distinct accessions. The analysis of molecular variance (AMOVA) reflected maximum variations (75%) are due to differences within populations. The implemented clustering algorithms, i.e., STRUCTURE, neighbor-joining analysis and principal coordinate analysis (PCoA) separated the studied germplasm on the basis of their geographical locations. Diversity indices for STRUCTURE-based populations showed that subpopulation A is more diverse population than the rest of the populations, for such reason, individuals belonging to this subpopulation should be used for reintroduction or reinforcement plans of rosewood conservation. We envisage that molecular characterization of Peruvian rosewood germplasm with DArTseq markers will provide a platform for the conservation, management and restoration of endangered rosewood in upcoming years.