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1.
Fruit bats of the genus Pteropus are important contributors to ecosystem maintenance on islands through their roles as pollinators and seed dispersers. However, island faunas are the most prone to extinction and there is a real need to assess the possible genetic implications of population reductions in terms of extinction risk. An effective method of ameliorating extinction risk in endangered species is the establishment of captive populations ex situ. The effectiveness of captive breeding programmes may be assessed by comparing the genetic variability of captive colonies to that of wild counterparts. Here, we use polymorphic microsatellite loci to assess genetic variability in wild, critically endangered Rodrigues fruit bats (Pteropus rodricensis, Dobson 1878) and we compare this variability to that in a captive colony. We document remarkable conservation of genetic variability in both the wild and captive populations, despite population declines and founder events. Our results demonstrate that the wild population has withstood the negative effects of population reductions and that captive breeding programmes can fulfil the goals of retaining genetic diversity and limiting inbreeding.  相似文献   

2.
Across species, diversity at the major histocompatibility complex (MHC) is critical to individual disease resistance and, hence, to population health; however, MHC diversity can be reduced in small, fragmented, or isolated populations. Given the need for comparative studies of functional genetic diversity, we investigated whether MHC diversity differs between populations which are open, that is experiencing gene flow, versus populations which are closed, that is isolated from other populations. Using the endangered ring‐tailed lemur (Lemur catta) as a model, we compared two populations under long‐term study: a relatively “open,” wild population (n = 180) derived from Bezà Mahafaly Special Reserve, Madagascar (2003–2013) and a “closed,” captive population (n = 121) derived from the Duke Lemur Center (DLC, 1980–2013) and from the Indianapolis and Cincinnati Zoos (2012). For all animals, we assessed MHC‐DRB diversity and, across populations, we compared the number of unique MHC‐DRB alleles and their distributions. Wild individuals possessed more MHC‐DRB alleles than did captive individuals, and overall, the wild population had more unique MHC‐DRB alleles that were more evenly distributed than did the captive population. Despite management efforts to maintain or increase genetic diversity in the DLC population, MHC diversity remained static from 1980 to 2010. Since 2010, however, captive‐breeding efforts resulted in the MHC diversity of offspring increasing to a level commensurate with that found in wild individuals. Therefore, loss of genetic diversity in lemurs, owing to small founder populations or reduced gene flow, can be mitigated by managed breeding efforts. Quantifying MHC diversity within individuals and between populations is the necessary first step to identifying potential improvements to captive management and conservation plans.  相似文献   

3.
Population structure and genetic diversity were examined using partial mitochondrial cytochrome b gene sequences of four wild, one reintroduced, and five captive populations of the endangered cyprinid Hemigrammocypris rasborella from three river systems in the easternmost region of the species’ range in Shizuoka Prefecture, central Honshu, Japan. We detected loss of genetic diversity from portions of the wild and captive populations, as well as suspected nonindigenous haplotypes in some captive, reintroduced, and even wild populations. Given the population structure revealed, we suggest that the populations should be managed with consideration for both the endemism and viability (avoidance of inbreeding depression) of the local populations.  相似文献   

4.
The endemic Jamaican boa (or “yellow boa”, Epicrates subflavus) is a vulnerable species of the Caribbean biodiversity hotspot whose natural populations greatly declined mainly due to predation by introduced species, human persecution, and habitat destruction. A captive breeding program was initiated in 1976 and rationalized in 2002 by the establishment of a European Endangered Species Program. During the last 30 years, more than 600 offspring, of which 80 are still alive today, have been produced and distributed among European host institutions and privates. Here, using nine nuclear microsatellite loci and a fragment of the mitochondrial cytochrome b gene, we (i) determine the natural population from which the founders originate, (ii) identify parental allocation errors and ambiguities in the studbook, and (iii) assess the genetic diversity and estimate levels of inbreeding of the current captive population based on loss of alleles, variance in reproductive success, and relatedness among individuals. Combining measures of relatedness derived from multilocus genotypes with practical parameters such as age of animals and localization of host institutions, we propose mating groups that would maximize genetic diversity in the captive population of the Jamaican boa. Our analyses provide guidance for a more efficient breeding program that, in turn, could be used as the starting point of a repatriation program to increase the probability of the species long-term survival. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

5.
The cross compatible wild relatives of crops have furnished valuable genes for crop improvement. Understanding the genetics of these wild species may enhance their further use in breeding. In this study, sequence variation of the nuclear Lhs1 gene was used to investigate the population genetic structure and gene flow of Oryza rufipogon and O. nivara, two wild species most closely related to O. sativa. The two species diverge markedly in life history and mating system, with O. rufipogon being perennial and outcrossing and O. nivara being annual and predominantly inbreeding. Based on sequence data from 105 plants representing 11 wild populations covering the entire geographic range of these wild species, we detected significantly higher nucleotide variation in O. rufipogon than in O. nivara at both the population and species levels. At the population level the diversity in O. rufipogon (Hd = 0.712; θ sil = 0.0017) is 2–3 folds higher than that in O. nivara (Hd = 0.306; θ sil = 0.0005). AMOVA partitioning indicated that genetic differentiation among O. nivara populations (78.2%) was much higher than that among O. rufipogon populations (52.3%). The different level of genetic diversity and contrasting population genetic structure between O. rufipogon and O. nivara might be explained by their distinct life histories and mating systems. Our simulation using IM models demonstrated significant gene flow from O. nivara to O. rufipogon, indicating a directional introgression from the annual and selfing species into the perennial and outcrossing species. The ongoing introgression has played an important role in shaping current patterns of genetic diversity of these two wild species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

6.
Ex situ management is an important conservation tool that allows the preservation of biological diversity outside natural habitats while supporting survival in the wild. Captive breeding followed by re‐introduction is a possible approach for endangered species conservation and preservation of genetic variability. The Cayman Turtle Centre Ltd was established in 1968 to market green turtle (Chelonia mydas) meat and other products and replenish wild populations, thought to be locally extirpated, through captive breeding. We evaluated the effects of this re‐introduction programmme using molecular markers (13 microsatellites, 800‐bp D‐loop and simple tandem repeat mitochondrial DNA sequences) from captive breeders (N = 257) and wild nesting females (N = 57) (sampling period: 2013–2015). We divided the captive breeders into three groups: founders (from the original stock), and then two subdivisions of F1 individuals corresponding to two different management strategies, cohort 1995 (“C1995”) and multicohort F1 (“MCF1”). Loss of genetic variability and increased relatedness was observed in the captive stock over time. We found no significant differences in diversity among captive and wild groups, and similar or higher levels of haplotype variability when compared to other natural populations. Using parentage and sibship assignment, we determined that 90% of the wild individuals were related to the captive stock. Our results suggest a strong impact of the re‐introduction programmme on the present recovery of the wild green turtle population nesting in the Cayman Islands. Moreover, genetic relatedness analyses of captive populations are necessary to improve future management actions to maintain genetic diversity in the long term and avoid inbreeding depression.  相似文献   

7.
In closed captive populations, where dispersal is not possible, kin recognition and behavioral avoidance are the only mechanisms by which closely related individuals can avoid inbreeding. In the absence of avoidance, a loss of genetic diversity is inevitable in successive generations.In the 1980s, the CIRMF in Gabon established a small breeding group of sun-tailed monkeys (Cercopithecus solatus) with 4 individuals, and subsequently 17 births have been registered. We aimed to describe via microsatellite genotyping the reproductive system in the colony of Cercopithecus solatus, to evaluate the loss of genetic diversity with succeeding generations, and to evaluate consequences of inbreeding depression on a measure of the lifespan reproductive success of females giving birth to inbred vs. noninbred offspring. During the 11-yr period for which data are available, only alpha males sired offspring, confirming a one-male social organization. They reproduced only during their period of tenure. Two of the 3 alpha males were responsible for all the infants born. Genetic diversity decreased and inbreeding coefficients increased with successive generations. Interbirth interval was increased following the birth of an inbred infant, indicating possible increased maternal costs of rearing inbred infants. Loss of genetic variability in this captive group of sun-tailed monkeys has led to significant inbreeding depression and demonstrates the importance of male-mediated gene flow in restricted one-male harem breeding groups.  相似文献   

8.
Captive breeding programmes aim to provide an insurance against extinction in the wild and a source for re-introductions making it essential to minimise genetic threats, and maximise representation of wild adaptive genetic diversity. As such, genetic assessments of captive breeding programmes are increasingly common. However, these rarely include comprehensive comparisons with wild populations and typically neutral, rather than adaptive, genetic diversity is assayed. Moreover, genetic data are rarely integrated with studbook information, which enables the most robust assessments. Here we use the European captive African wild dog (Lycaon pictus) population to demonstrate the utility of this combined approach. Specifically, we combined studbook pedigree information with genetic assessments of captive and wild samples at both neutral markers and a locus thought to be important for adaptation (a gene at the Major Histocompatibility Complex, MHC). With these data we were able to evaluate founder origin and representation, as well as the distribution and origin of genetic variation within the captive population. We found discrepancies between diversity metrics derived from neutral and adaptive markers and pedigree versus genetic derived inbreeding estimates. Overall, however, we found a large proportion of genetic diversity from wild populations to be conserved in the captive population, much of which can be attributed to recent imports from outside of the European breeding programme. Nonetheless, we also found a high incidence of inbreeding and very skewed founder contributions. Based on these results, we proposed and implemented a genetic management plan to prevent further losses of diversity and reduce inbreeding.  相似文献   

9.
The South China tiger (Panther tigris amoyensis) is critically endangered with 73 remaining individuals living in captivity, all derived from six wild founders since 1963. The population shows a low level of juvenile survivorship and reproductive difficulties, and faces a huge conservation challenge. In this study, inbreeding depression and genetic diversity decline were examined by using pedigree data and 17 microsatellites. The constant B, which is related to the number of lethal equivalents, was estimated to be 0 for the offspring of noninbred parents, but was >0 for the offspring of inbred parents and for all offspring. Percentage of successfully breeding tigers inversely correlated with inbreeding level (r = −0.626, α = 0.05). Taken together, these findings suggest the population is suffering from inbreeding depression in juvenile survivorship and fecundity. No significant correlation was detectable for the mean litter size with f of either dams (r = −0.305, α = 0.46) or kittens (r = 0.105, α = 0.71), indicating litter size was not strongly subject to inbreeding depression. The average number of alleles per locus was 4.24 ± 1.03 (SE), but effective number of alleles was only 2.53 ± 0.91. Twenty-one alleles carried by early breeders at 13 loci were absent in the present breeders and potential breeders. Multilocus heterozygosity was inversely correlated with inbreeding levels (r = −0.601, α = 0.004). These findings suggest rapid allelic diversity loss is occurring in this small captive population and that heterozygosity is being lost as it becomes more inbred. Our phylogenetic analysis supports past work indicating introgression from northern Indochinese tigers in the population. As no wild representatives of the South China tiger can be added to the captive population, we may consider the alternate scenario of further introgression in the interest of countering inbreeding depression and declining genetic diversity.  相似文献   

10.
The objectives of this study were to assess the level of genetic variability and population differentiation within captive populations of an endangered large mammal, Baird's tapir (Tapirus bairdii). We genotyped 37 captive animals from North American (NA) and Central American (CA) zoos and conservation ranches using six polymorphic microsatellite loci. Standard indices of genetic variability (allelic richness and diversity, and heterozygosity) were estimated and compared between captive populations, and between captive and wild population samples. In addition, we evaluated levels of population differentiation using Weir and Cockerham's version of Wright's F-statistics. The results indicate that the NA and CA captive populations of Baird's tapirs have retained levels of genetic variability similar to that measured in a wild population. However, inbreeding coefficients estimated from the molecular data indicate that the CA captive population is at increased risk of losing genetic variability due to inbreeding. Despite this, estimated levels of population differentiation indicate limited divergence of the CA captive population from the wild population. Careful management appears to have kept inbreeding coefficients low in the NA captive population; however, population differentiation levels indicate that the NA population has experienced increased divergence from wild populations due to a founder effect and isolation. Based on these results, we conclude that intermittent exchanges of Baird's tapirs between the NA and CA captive populations will benefit both populations by increasing genetic variability and effective population size, while reducing inbreeding and divergence from wild populations. Zoo Biol 23:521–531, 2004. © 2004 Wiley-Liss, Inc.  相似文献   

11.
The genetic diversity and population structure of 136 captive Thai elephants (Elephas maximus) with known region of origin were investigated by analysis of 14 highly polymorphic microsatellite loci. We did not detect significant indications of inbreeding and only a low differentiation of elephants from different regions. This is probably explained by the combined effects of isolation by distance and exchange between different regions or between captive and wild elephant populations. Estimates of effective population sizes were in the range of 90–240 individuals, which emphasizes the necessity to guard against inbreeding as caused by the current use of a restricted number of breeding bulls.  相似文献   

12.
Social tolerance crucially affects the life of group‐living animals as it can influence, among other things, their competitive regimes, access to food, learning behavior, and recruitment. However, social tolerance tests were mainly conducted in semi‐free or captive populations, and we know little about the behavioral mechanisms and consequences of social tolerance under natural conditions. We therefore developed a co‐feeding experiment to measure social tolerance in groups of wild and captive animals across two primate species. Specifically, we recorded the social tolerance level of redfronted lemurs (Eulemur rufifrons, four wild, one captive group) and ringtailed lemurs (Lemur catta, three wild, three captive groups) by presenting a clumped food resource in an experimental arena, and recorded patterns of resource use during the experiment. Because redfronted lemurs exhibit lower levels of decided conflicts than ringtailed lemurs, we predicted that they would be socially more tolerant. The probability for an individual to feed in the arena was higher in redfronted lemurs than in ringtailed lemurs. In addition, in both species, the probability for an individual to feed in the arena was higher in the captive populations than in their wild counterparts, suggesting that proximate factors, such as a relaxation of feeding competition in captivity, may adapt species‐specific levels of social tolerance to local levels of food availability. Hence, the number of individuals co‐feeding on a valuable food resource appears to be a useful proxy of social tolerance that could be measured with this experimental setup in other wild and captive species as well.  相似文献   

13.
The peregrine falcon (Falco peregrinus) population in southern Scandinavia was almost extinct in the 1970’s. A successful reintroduction project was launched in 1974, using captive breeding birds of northern and southern Scandinavian, Finnish and Scottish origin. We examined the genetic structure in the pre-bottleneck population using eleven microsatellite markers and compared the data with the previously genotyped captive breeding population and contemporary wild population. Museum specimens between 53 and 130 years old were analyzed. Despite an apparent loss of historical genetic diversity, the contemporary population shows a relatively high level of genetic variation. Considerable gene introgression from captive breeding stock used to repopulate the former range of southern Scandinavian peregrines may have altered the genetic composition of this population. Both the historical and contemporary northern and southern Scandinavian populations are genetically differentiated. The reintroduction project implemented in the region and the use of non-native genetic stock likely prevented the southern Scandinavian population from extinction and thus helped maintain the level of genetic diversity and prevent inbreeding depression. The population is rapidly increasing in numbers and range and shows no indication of reduced fitness or adaptive capabilities in the wake of the severe bottleneck and the reintroduction.  相似文献   

14.
Western lowland gorillas (Gorilla gorilla gorilla) are designated as critically endangered and wild populations are dramatically declining as a result of habitat destruction, fragmentation, diseases (e.g., Ebola) and the illegal bushmeat trade. As wild populations continue to decline, the genetic management of the North American captive western lowland gorilla population will be an important component of the long‐term conservation of the species. We genotyped 26 individuals from the North American captive gorilla collection at 11 autosomal microsatellite loci in order to compare levels of genetic diversity to wild populations, investigate genetic signatures of a population bottleneck and identify the genetic structure of the captive‐born population. Captive gorillas had significantly higher levels of allelic diversity (t7 = 4.49, = 0.002) and heterozygosity (t7 = 4.15, = 0.004) than comparative wild populations, yet the population has lost significant allelic diversity while in captivity when compared to founders (t7 = 2.44, = 0.04). Analyses suggested no genetic evidence for a population bottleneck of the captive population. Genetic structure results supported the management of North American captive gorillas as a single population. Our results highlight the utility of genetic management approaches for endangered nonhuman primate species.  相似文献   

15.
The analysis of 135 mitochondrial D-loop sequences of the Iberian autochthonous red-legged partridge (Alectoris rufa) from wild population hunting bags from various locations and fowl runs in Spain yielded 37 different haplotypes. Among these, three haplotypes correspond to chukar partridges (Alectoris chukar), indicating genetic introgression from birds illegally introduced for restocking: three individuals carrying such haplotypes where found in natural populations, one appeared among those sampled on a mass reproduction farm and the remaining 10 in another fowl-run. The geographical origin of the contaminating chukar haplotypes could be assigned to the most easterly area of the chukar partridge geographical distribution in China. Molecular diversity parameters in the A. rufa samples indicate a considerable amount of genetic variation. ΦST showed significant differences among populations that are not explained by geographical distance alone. Particularly, one northern population (Palencia) shows a certain degree of genetic differentiation that could reflect a previously suggested subspecies division. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

16.
Among the 14 extant species of the genus Marmota the Vancouver Island marmot (Marmota vancouverensis) is the most endangered. In 2007 as few as 85 individuals were left in the wild, with an additional 162 individuals maintained in captivity. To facilitate genetic monitoring of both wild and captive populations, polymorphic genetic markers were identified. Thirty-three different microsatellite loci were tested for amplification and variability in ≥30 wild-born individuals. Only 11 of these loci proved to be polymorphic and were subsequently analysed in 105 samples collected from wild Vancouver Island marmots. The average number of alleles (A) at those 11 loci was only 2.1, and the intraspecific variation (H E between 8 and 23% within colonies) was low compared to other marmot species. Variation within the small and geographically isolated Mt. Washington colony was particularly low (A = 1.3, H E = 0.08). Genetic distances between the Mt. Washington colony (11 individuals) and those of the Nanaimo Lakes region (94 individuals) on southern Vancouver Island were large (D values ranging from 0.42 to 0.50), while genetic distances among colonies within the latter area were much smaller (D values from 0.01 to 0.13). Given the low within-population genetic variation, and the resulting risk of inbreeding depression at Mt. Washington, we support the decision to maximize overall genetic variation of the species by crossbreeding marmots from the two different areas despite the possibility of local adaptation.  相似文献   

17.
The species Avicennia germinans in natural and reforested areas was analyzed to obtain information about its genetic diversity in a highly disturbed mangrove ecosystem and to generate a useful tool for determining the donor and receptor populations of propagules. Tissue of 149 individuals was collected in the protected areas of the Tayrona National Natural Park (Tayrona-NNP) and the Salamanca Island Parkway (Salamanca-IP). A total of 38 alleles were found in seven microsatellite loci, leading to the detection of high levels of heterozygosity in the two protected areas. The impact of the highway on the Salamanca-IP-south population was shown when the inbreeding coefficient from younger individuals was compared with older ones; inbreeding increased 4.2 times. The inbreeding coefficient in the reforested area was 2.2 times higher than that in the Salamanca-IP-south zone. Thus, for future reforestations in this area, the collecting of propagules should come from two sectors—one to the north of the highway including Tayrona-NNP and the other to the south. Finally, we consider that the viability of the reforested population in the short and medium term would be improved if good reforestation practices are implemented for A. germinans. Handling editor: C. Sturmbauer  相似文献   

18.
Genetic diversity is positively linked to the viability and evolutionary potential of species but is often compromised in threatened taxa. Genetic rescue by gene flow from a more diverse or differentiated source population of the same species can be an effective strategy for alleviating inbreeding depression and boosting evolutionary potential. The helmeted honeyeater Lichenostomus melanops cassidix is a critically endangered subspecies of the common yellow‐tufted honeyeater. Cassidix has declined to a single wild population of ~130 birds, despite being subject to intensive population management over recent decades. We assessed changes in microsatellite diversity in cassidix over the last four decades and used population viability analysis to explore whether genetic rescue through hybridization with the neighbouring Lichenostomus melanops gippslandicus subspecies constitutes a viable conservation strategy. The contemporary cassidix population is characterized by low genetic diversity and effective population size (Ne < 50), suggesting it is vulnerable to inbreeding depression and will have limited capacity to evolve to changing environments. We find that gene flow from gippslandicus to cassidix has declined substantially relative to pre‐1990 levels and argue that natural levels of gene flow between the two subspecies should be restored. Allowing gene flow (~4 migrants per generation) from gippslandicus into cassidix (i.e. genetic rescue), in combination with continued annual release of captive‐bred cassidix (i.e. demographic rescue), should lead to positive demographic and genetic outcomes. Although we consider the risk of outbreeding depression to be low, we recommend that genetic rescue be managed within the context of the captive breeding programme, with monitoring of outcomes.  相似文献   

19.
Wu HL  Fang SG 《Biochemical genetics》2005,43(7-8):407-416
Genetic diversities based on the mtDNA control region were measured for both a wild population (n = 26) and a captive population (n = 18) of the black muntjac. In total, nine haplotypes were obtained from 44 samples. The wild population exhibited a low nucleotide diversity (π = 0.00562), which suggests that the black muntjac had a small effective population size historically. In contrast to its low nucleotide diversity, haplotype diversity (h = 0.862) of the wild population was relatively high. Haplotype distribution among local samples shows a distinct difference. As anticipated because of the paucity of available founders, nucleotide diversity (π = 0.00214) of the captive population was very low. Additionally, a high degree of haplotype identity and an obvious haplotype frequency bias was revealed in the captive population, which implies that the current breeding program should be readjusted to balance distributions of haplotypes, and some new founders should be introduced to the captive population to alleviate potential inbreeding depression.  相似文献   

20.
Population augmentation with translocated individuals has been shown to alleviate the effects of bottlenecks and drift. The first step to determine whether restoration for genetic considerations is warranted is to genetically monitor reintroduced populations and compare results to those from the source. To assess the need for genetic restoration, we evaluated genetic diversity and structure of reintroduced (n = 3) and captive populations of the endangered black-footed ferret (Mustela nigripes). We measured genotypic changes among populations using seven microsatellite markers and compared phenotypic changes with eight morphometric characters. Results indicated that for the population which rapidly grew post-reintroduction, genetic diversity was equivalent to the captive, source population. When growth languished, only the population that was augmented yearly maintained diversity. Without augmentation, allelic diversity declined precipitously and phenotypic changes were apparent. Ferrets from the genetically depaupertate population had smaller limbs and smaller overall body size than ferrets from the two populations with greater diversity. Population divergence (F ST = 0.10 ± 0.01) was surprisingly high given the common source of populations. Thus, it appears that 5–10 years of isolation resulted in both genotypic divergence and phenotypic changes to populations. We recommend translocation of 30–40 captive individuals per annum to reintroduction sites which have not become established quickly. This approach will maximize the retention of genetic diversity, yet maintain the beneficial effects of local adaptation without being swamped by immigration.  相似文献   

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