Stability of genetic structure and effective population size inferred from temporal changes of microsatellite DNA polymorphisms in the land snail Helix aspersa (Gastropoda: Helicidae)

Temporal evolution of genetic variability may have far-reaching consequences for a diverse array of evolutionary processes. Within the polders of the Bay of Mont-Saint-Michel (France), populations of the land snail Helix aspersa are characterized by a metapopulation structure with occasional extinction processes resulting from farming practices. A temporal survey of genetic structure in H . aspersa was carried out using variability at four microsatellite loci, in ten populations sampled two years apart. Levels of within-population genetic variation, as measured by allelic richness, H _e or F _is , did not change over time and similar levels of population differentiation were demonstrated for both sampling years. The extent of genetic differentiation between temporal samples of the same population established (i) a stable structure for six populations, and (ii) substantial genetic changes for four populations. Using classical F -statistics and a maximum likelihood method, estimates of the effective population size ( N _e) illustrated a mixture of stable populations with high N _e, and unstable populations characterized by very small N _e estimates (of 5–11 individuals). Owing to human disturbances, intermittent gene flow and genetic drift are likely to be the predominant evolutionary processes shaping the observed genetic structure. However, the practice of multiple matings and sperm storage is likely to provide a reservoir of variability, minimizing the eroding genetic effects of population size reduction and increasing the effective population size.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 89–102.     

Genetic estimates of contemporary effective population size: what can they tell us about the importance of genetic stochasticity for wild population persistence?

Genetic stochasticity due to small population size contributes to population extinction, especially when population fragmentation disrupts gene flow. Estimates of effective population size ( N _e) can therefore be informative about population persistence, but there is a need for an assessment of their consistency and informative relevance. Here we review the body of empirical estimates of N _e for wild populations obtained with the temporal genetic method and published since Frankham's (1995 ) review. Theoretical considerations have identified important sources of bias for this analytical approach, and we use empirical data to investigate the extent of these biases. We find that particularly model selection and sampling require more attention in future studies.
We report a median unbiased N _e estimate of 260 (among 83 studies) and find that this median estimate tends to be smaller for populations of conservation concern, which may therefore be more sensitive to genetic stochasticity. Furthermore, we report a median N _e/ N ratio of 0.14, and find that this ratio may actually be higher for small populations, suggesting changes in biological interactions at low population abundances. We confirm the role of gene flow in countering genetic stochasticity by finding that N _e correlates strongest with neutral genetic metrics when populations can be considered isolated. This underlines the importance of gene flow for the estimation of N _e, and of population connectivity for conservation in general. Reductions in contemporary gene flow due to ongoing habitat fragmentation will likely increase the prevalence of genetic stochasticity, which should therefore remain a focal point in the conservation of biodiversity.     

Loss of genetic variation and effective population size of Kirikuchi charr: implications for the management of small, isolated salmonid populations

Small, isolated populations may face extinction due to a combination of inbreeding depression and other threats. Effective population size ( N _e) is one comprehensive measure that allows us to evaluate the genetic status of a population, and to make management decisions regarding genetic viability. We simulated loss of genetic variation and estimated N _e for two small, isolated populations of Kirikuchi charr Salvelinus leucomaenis japonicus , the endangered, southernmost local populations of the genus Salvelinus in the world, using VORTEX, an individual-based stochastic PVA model. Approximately half of the genetic variation was lost over 200 years regardless of census population size and demographic parameters, and N _e estimates were roughly 50 in each of the two populations, suggesting the possibility of inbreeding depression. The target population size of N _e>500, by securing long-term viability, is several times that of the present size of each of the populations studied, and no local habitats maintaining such a target number are considered to exist. The results strongly indicate a need for recovering natural connections and potential gene flow among local populations. However, the impending threat to these populations from non-native charr widely distributed throughout the drainage has prevented the recovery of the connections. Given the small N _e of the two populations, it would be necessary to retain gene flow artificially within or across local populations. This will be true of many other salmonid populations that have been isolated or fragmented recently.     

Allozyme variation and population structure of the very narrow endemic Seseli farrenyi (Apiaceae)

Analyses have been made of allozyme variation of the narrow endemic species Seseli farrenyi Molero & J. Pujadas (Apiaceae), which has only three known populations in Catalonia with a total of around 2000 individuals. All three populations were sampled and subjected to starch gel electrophoresis. Nine enzymes were resolved and 14 loci were interpreted. We detected high values of polymorphism ( P = 83.3%, A = 3.0, H _e = 0.297), far exceeding those expected for endemic species ( P = 26.3%, A = 1.39, H _e = 0.063). Genetic diversity was greater within populations than among populations, and the value of gene flow was very high ( Nm = 5.85). Most loci showed deviations from Hardy– Weinberg equilibrium, possibly due to the presence of subpopulations. The main threats to this species are human activities (tourism, fires), while natural threats are minimal due to its high genetic diversity. Finally, we propose some conservation measures which include both in situ and ex situ strategies. © 2000 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 305–314.     

Contrasting levels of genetic diversity between the common, self-compatible Liparis kumokiri and rare, self-incompatible Liparis makinoana (Orchidaceae) in South Korea

Levels of allozyme variation and intrapopulation spatial genetic structure of the two terrestrial clonal orchids Liparis kumokiri , a self-compatible relatively common species, and L. makinoana , a self-incompatible rare species, were examined for 17 ( N  = 1875) and four ( N  = 425) populations, respectively, in South Korea. Populations of L. makinoana harboured high levels of genetic variation ( H _e = 0.319) across 15 loci. In contrast, L. kumokiri exhibited a complete lack of allozyme variation ( H _e = 0.000). Considering the lack of genetic variability, it is suggested that current populations of L. kumokiri in South Korea originated from a genetically depauperate ancestral population. For L. makinoana , a significant deficit of heterozygosity (mean F _IS = 0.198) was found in population samples excluding clonal ramets, suggesting that pollen dispersal is localized, generating biparental inbreeding. The significant fine-scale genetic structuring (≤ 2 m) found in a previous study, in addition to the moderate levels of population differentiation ( F _ST = 0.107) and the significant relationship between genetic and geographical distances ( r  = 0.680) found here, suggests a leptokurtic distribution of seed dispersal for L. makinoana . Although populations of L. makinoana harbour high levels of genetic variation, they are affected by a recent genetic bottleneck. This information suggests that genetic drift and limited gene flow could be the main evolutionary forces for speciation of a species-rich genus such as Liparis .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 41–48.     

Population genetic structure and effective population size of ayu (Plecoglossus altivelis), an amphidromous fish

The temporal and spatial population genetic structure of ayu Plecoglossus altivelis (Salmoniformes: Plecoglossidae), an amphidromous fish, was examined using analysis of variation at six microsatellite DNA loci. Intracohort genetic diversities, as measured by the number of alleles and heterozygosity, were similar among six cohorts (2001–2006) within a population (Nezugaseki River), with the mean number of alleles per cohort ranging from 11·0 to 12·5 and the expected heterozygosity ranging from 0·74 to 0·77. Intrapopulational genetic diversities were also similar across the three studied populations along the 50 km coast, with the mean number of alleles and the expected heterozygosity ranging from 11·33 to 11·67 and from 0·75 to 0·76, respectively. The authors observed only one significant difference in pair-wise population differentiation ( F _ST-value) between the cohorts within a population and among three populations. Estimates of the effective population size ( N _e) based on maximum-likelihood method yielded small values (ranging from 94·8 to 135·5), whereas census population size ranged from c. 4800 to 24 000. As a result, the ratio of annual effective population sizes to census population size ( N _e/ N ) ranged from 0·004 to 0·023. These estimates of N _e/ N agree more closely with estimates for marine fishes than that of the larger estimates for freshwater fishes. The present study suggests that ayu which is highly fecund and shows low survival during the early life stages is also characterized by having low value of N _e/ N , similar to marine species with a pelagic life cycle.     

Population genetic structure of the butterfly Melitaea didyma (Nymphalidae) along a northern distribution range border

The population genetic structure of the butterfly Melitaea didyma was studied along the northern distribution range border in Central Germany by means of allozyme electrophoresis. Individuals were sampled from a total of 21 habitat patches from four regions, and two provinces. Sampling was designed to estimate local vs. regional differentiation. High levels of variability were found, H _e= 0.14–0.21. The mean expected sample heterozygosity from one region, Mosel, was significantly lower than from the Hammelburg region, H _e= 0.17 and 0.19, respectively. Two hierarchical levels of genetic differentiation were found. Within regions individuals sampled from different patches behaved as belonging to one population with high levels of gene flow (Hammelburg F _ST= 0.015, Mosel F _ST= 0.044), though local isolation barriers did create a substructuring of these populations. The inbreeding coefficients, F _IS, were constant over all sample levels, suggesting a similar distribution of habitat patches within regions. Between regions gene flow was limited. An isolation by distance analysis indicated that the hierarchical structure, at the provincial level, may be breaking down due to isolation of regional populations. A more general observation was that the sampling design may greatly have influenced the estimation of genetic differentiation. Depending on which samples were included, overall F _ST estimates ranged from 0.059–0.090.     

Effective number of breeding adults in Bufo bufo estimated from age-specific variation at minisatellite loci

Estimates of the effective number of breeding adults were derived for three semi-isolated populations of the common toad Bufo bufo based on temporal (i.e. adult-progeny) variance in allele frequency for three highly polymorphic minisatellite loci. Estimates of spatial variance in allele frequency among populations and of age-specific measures of genetic variability are also described. Each population was characterized by a low effective adult breeding number ( N _b) based on a large age-specific variance in mini-satellite allele frequency. Estimates of N _b (range 21–46 for population means across three loci) were ≊ 55–230-fold lower than estimates of total adult census size. The implications of low effective breeding numbers for long-term maintenance of genetic variability and population viability are discussed relative to the species' reproductive ecology, current land-use practices, and present and historical habitat modification and loss. The utility of indirect measures of population parameters such as N _b and N _e based on time-series data of minisatellite allele frequencies is discussed relative to similar measures estimated from commonly used genetic markers such as protein allozymes.     

Genetic diversity and effective size of the Atlantic salmon Salmo salar L. inhabiting the River Eo (Spain) following a stock collapse

Historic angling records suggest the occurrence of a drastic decline in the River Eo (Spain) Atlantic salmon population size during the past two decades, as a result of overexploitation and habitat deterioration. In recent years, the population has been apparently recovering, and the present study is aimed to report information on the level of genetic diversity and the effective size of the current population as these may have immediate consequences for its conservation. Eighty-six salmon from two temporal groups (1998–1999 and 2004–2006), representing three generations, were genotyped using a panel of eight microsatellites. Inspite of the recent decline in census numbers and the detection of the signs of a population bottleneck, the population exhibits a high level of genetic diversity, similar to that from other populations, and almost unchanged during the period of study [average allelic richness ( A ) = 14·0 and 13·9, and average heterozygosity ( H _e) = 0·843 and 0·851 in 1998–1999 and 2004–2006, respectively]. The effective population size ( N _e) estimated by two different temporal methods showed a consistent value around 80 salmon, whereas the estimates from the linkage disequilibrium (LD) method provided a value around 165 individuals for either sample. The recent growing number of salmon, as indicated by fisheries records, the relatively large estimates of the ratio N _e/ N (with range 0·23–0·44 for the temporal estimates and 0·31–0·59 for the LD estimates) and the high levels of diversity found suggest that the population has not been greatly affected by the historical census declines and can be expected to recover in the future.     

Usefulness of molecular markers for detecting population bottlenecks via monitoring genetic change

It is important to detect population bottlenecks in threatened and managed species because bottlenecks can increase the risk of population extinction. Early detection is critical and can be facilitated by statistically powerful monitoring programs for detecting bottleneck-induced genetic change. We used Monte Carlo computer simulations to evaluate the power of the following tests for detecting genetic changes caused by a severe reduction in a population's effective size ( N _e): a test for loss of heterozygosity, two tests for loss of alleles, two tests for change in the distribution of allele frequencies, and a test for small N _e based on variance in allele frequencies (the 'variance test'). The variance test was most powerful; it provided an 85% probability of detecting a bottleneck of size N _e = 10 when monitoring five microsatellite loci and sampling 30 individuals both before and one generation after the bottleneck. The variance test was almost 10-times more powerful than a commonly used test for loss of heterozygosity, and it allowed for detection of bottlenecks before 5% of a population's heterozygosity had been lost. The second most powerful tests were generally the tests for loss of alleles. However, these tests had reduced power for detecting genetic bottlenecks caused by skewed sex ratios. We provide guidelines for the number of loci and individuals needed to achieve high-power tests when monitoring via the variance test. We also illustrate how the variance test performs when monitoring loci that have widely different allele frequency distributions as observed in five wild populations of mountain sheep ( Ovis canadensis ).     

Low genetic diversity in the bottlenecked population of endangered non-native banteng in northern Australia

Undomesticated (wild) banteng are endangered in their native habitats in Southeast Asia. A potential conservation resource for the species is a large, wild population in Garig Gunak Barlu National Park in northern Australia, descended from 20 individuals that were released from a failed British outpost in 1849. Because of the founding bottleneck, we determined the level of genetic diversity in four subpopulations in the national park using 12 microsatellite loci, and compared this to the genetic diversity of domesticated Asian Bali cattle, wild banteng and other cattle species. We also compared the loss of genetic diversity using plausible genetic data coupled to a stochastic Leslie matrix model constructed from existing demographic data. The 53 Australian banteng sampled had average microsatellite heterozygosity (HE) of 28% compared to 67% for outbred Bos taurus and domesticated Bos javanicus populations. The Australian banteng inbreeding coefficient (F) of 0.58 is high compared to other endangered artiodactyl populations. The 95% confidence bounds for measured heterozygosity overlapped with those predicted from our stochastic Leslie matrix population model. Collectively, these results show that Australian banteng have suffered a loss of genetic diversity and are highly inbred because of the initial population bottleneck and subsequent small population sizes. We conclude that the Australian population is an important hedge against the complete loss of wild banteng, and it can augment threatened populations of banteng in their native range. This study indicates the genetic value of small populations of endangered artiodactyls established ex situ.     

The population genetic effects of ancestry and admixture in a subdivided cattle breed

The genetic structure of the Dexter, a minority cattle breed with complex demographic history, was investigated using microsatellite markers and a range of statistical approaches designed to detect both admixture and genetic drift. Modern representatives of two putative ancestral populations, the Devon and Kerry, together with the different populations of the Dexter, which have experienced different demographic histories, were analysed. Breed units showed comparatively high levels of genetic variability ( H _E = 0.63–0.68); however, distinct genetic subgroups were detected within the Dexter, which could be attributed to known demographic events. Much lower diversity was identified in three small, isolated Dexter populations ( H _E = 0.52–0.55) and higher differentiation ( F _ST > 0.13) was found. For one of these populations, where strong selection has taken place, we also found evidence of a demographic bottleneck. Three methods for quantifying breed admixture were applied and substantial method-based variation in estimates for the genetic contribution of the two proposed ancestral populations for each subdivision of the Dexter was found. Results were consistent only in the case of a group consisting of selected Traditional Dexter animals, where the ancestor of the modern Kerry breed was also determined as the greater parental contributor to the Dexter. The inconsistency of estimation of admixture proportions between the methods highlights the potentially confounding role of genetic drift in shaping small population structure, and the consequences of accurately describing population histories from contemporary genetic data.     

Fine-scale population structure in a desert amphibian: landscape genetics of the black toad (Bufo exsul)

Environmental variables can strongly influence a variety of intra- and inter-population processes, including demography, population structure and gene flow. When environmental conditions are particularly harsh for a certain species, investigating these effects is important to understanding how populations persist under difficult conditions. Furthermore, species inhabiting challenging environments present excellent opportunities to examine the effects of complex landscapes on population processes because these effects will often be more pronounced. In this study, I use 16 microsatellite loci to examine population structure, gene flow and demographic history in the black toad, Bufo exsul , which has one of the most restricted natural ranges of any amphibian. Bufo exsul inhabits four springs in the Deep Springs Valley high desert basin and has never been observed more than several meters from any source of water. My results reveal limited gene flow and moderately high levels of population structure ( F _ST = 0.051–0.063) between all but the two closest springs. I found that the geographic distance across the arid scrub habitat between springs is significantly correlated with genetic structure when distance accounts for topography and barriers to dispersal. I also found very low effective population sizes ( N _e = 7–30) and substantial evidence for historical population bottlenecks in all four populations. Together, these results suggest that the desert landscape and B.   exsul 's high habitat specificity contribute significantly to population structure and demography in this species and emphasize the importance of considering behavioural and landscape data in conservation genetic studies of natural systems.     

Long-term stability and effective population size in North Sea and Baltic Sea cod (Gadus morhua)

DNA from archived otoliths was used to explore the temporal stability of the genetic composition of two cod populations, the Moray Firth (North Sea) sampled in 1965 and 2002, and the Bornholm Basin (Baltic Sea) sampled in 1928 and 1997. We found no significant changes in the allele frequencies for the Moray Firth population, while subtle but significant genetic changes over time were detected for the Bornholm Basin population. Estimates of the effective population size ( N _e ) generally exceeded 500 for both populations when employing a number of varieties of the temporal genetic method. However, confidence intervals were very wide and N _e 's most likely range in the thousands. There was no apparent loss of genetic variability and no evidence of a genetic bottleneck for either of the populations. Calculations of the expected levels of genetic variability under different scenarios of N _e showed that the number of alleles commonly reported at microsatellite loci in Atlantic cod is best explained by N _e 's exceeding thousand. Recent fishery-induced bottlenecks can, however, not be ruled out as an explanation for the apparent discrepancy between high levels of variability and recently reported estimates of N _e  << 1000. From life history traits and estimates of survival rates in the wild, we evaluate the compatibility of the species' biology and extremely low N _e / N ratios. Our data suggest that very small N _e 's are not likely to be of general concern for cod populations and, accordingly, most populations do not face any severe threat of losing evolutionary potential due to genetic drift.     

Allozyme Diversity in Populations of Cymbidium goeringii (Orchidaceae)

Abstract: Using 14 allozyme loci, we investigated levels of genetic diversity within populations, and degree of genetic divergence among 24 populations of Cymbidium goeringii (Orchidaceae) in Korea and Japan. Cymbidium goeringii maintains high levels of genetic diversity both at population (mean expected heterozygosity, H _e = 0.238) and species levels (0.260). Means of H _e found in 24 populations were not significantly different from each other. About 90 % of the total variation in the species is common to all populations (mean G _ST = 0.108). No unique allele was found in any population. The indirect estimate of gene flow based on the mean G _ST was high ( Nm = 2.06). Nei's genetic identities for pairs of populations had high values (mean = 0.974 [SD = 0.013]). The Mantel-Z test showed a significant correlation between genetic distance and geographic distance. However, the mean G _ST value between 17 populations in Korea and seven Japanese populations was relatively low (0.029), even though the land connection between the southern Korean peninsula and southern Japanese archipelagos has not existed since the middle Pleistocene. Large numbers of small seeds of C. goeringii might travel long distances by wind from populations to populations both in Korea and Japan, increasing genetic diversity within populations and maintaining low genetic differentiation among populations.     

Genetic structure and population dynamics of a heteroecious plant pathogen Melampsora larici-epitea in short-rotation coppice willow plantations

Complex life strategies are common among plant pathogens belonging to rust fungi ( Uredinales ). The heteroecious willow rust Melampsora larici-epitea produces five spore stages and alternates on larch ( Larix ). To shed light on the epidemiology of this pathogen, amplified fragment length polymorphisms (AFLPs) were used to determine the genetic diversity and genetic structure of rust samples collected from coppice willow ( Salix ) plantations at three UK sites (LA, CA and MC) over three sampling dates (September 2000, July 2001 and September 2001). Of the total of 819 isolates, 465 were unique AFLP phenotypes and there was a shift in genotype diversity between the two seasons (0.67 in 2000 and 0.87–0.89 in 2001). No phenotypes were common between the two seasons within a site, suggesting that the rust did not overwinter as an asexual stage within plantations. A temporal analysis detected large amounts of genetic drift ( F _S = 0.15–0.26) between the two seasons and very small effective population sizes ( N _e  =  2–3) within sites. These results all point to a new colonization of the plantations by the rust in the second season (2001). The F _ST-analogue values were Φ_CT = 0.121, Weir and Cockerham's θ = 0.086 and the Bayesian estimate θ^B = 0.087–0.096. The results suggest that the sources of inoculum were somewhat localized and the same sources were mainly responsible for disease epidemics in LA and CA over the two seasons. The relatively low F _ST-values among sites (0.055–0.13) suggest the existence of significant gene flow among the three sampled sites.     

Genetics of the peripheral populations of the alpine bullhead, Cottus poecilopus (Scorpaeniformes, Cottidae) in Poland

The alpine bullhead ( Cottus poecilopus ) in Poland is highly polymorphic ( P for examined populations in the range of 0.0–0.45, mean P  = 0.11, P for species 0.64) in seven out of 11 loci studied ( Pgd-1, Mdh-1, Ck-1, Gpd-1, Gpd-2, Gpi-1, Gpi-2 ). However, they reveal very low heterozygosity (mean H _o = 0.007, mean H _e = 0.019), which may result from population subdivisions, small genetically effective size ( N _e) of some populations and frequent inbreeding, the latter being probably mediated through polygyny. The index of genetic differentiation ( G _ST) for the Polish metapopulation equals 0.48, which is relatively high. By far, the strongest are genetic differences between the Sudeten-Carpathian group and the Hańcza population. Gene flow between the Sudeten-Carpathian group and the Hańcza population is very limited and their divergence may have started as early as the last (Eemian) interglacial period.     

Large variations in the ratio of effective breeding and census population sizes between two species of pond-breeding anurans

The viability of wild populations is frequently assessed by monitoring adult census sizes ( N _c). This approach is particularly useful for pond-breeding amphibians, because assemblages during the breeding season are relatively easy to detect and count. However, it is the genetic effective population size ( N _e) or surrogates such as effective breeding population size ( N _b) that are of primary importance for long-term viability. Although N _c estimates of one anuran amphibian ( Bufo bufo ) in Britain were much larger than those of another ( Rana temporaria ) at the same sites, the ratios of N _b to N _c were much smaller in B. bufo than in R. temporaria. These differences were sufficiently great as to reverse the effective size order at one site, such that N _b for R. temporaria was larger than that for B. bufo. Differences in adult sex ratios at breeding sites probably contributed to lower N _b values in B. bufo populations compared with those of R. temporaria . The relationship of N _b to N _c can therefore vary dramatically even between similar species, to the extent that just monitoring N _c can give misleading impressions of relative effective breeding sizes and thus of population viability. It will be increasingly important to estimate N _e or N _b in wildlife populations for assessment of conservation priorities.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 365–372.     

Effectiveness of in situ and ex situ conservation of crop diversity. What a Phaseolus vulgaris L. landrace case study can tell us

The effectiveness of in situ (on-farm) and ex situ conservation strategies to maintain total genetic diversity was assessed in a threatened Phaseolus vulgaris L. landrace. Farmer seed lots (subpopulations) were sampled initially and then after in situ and ex situ multiplication (two locations). The number of plants used in the ex situ multiplications (120) was much larger than that normally used in germplasm bank procedures and the farmer seed lots were kept separate. In situ, the landrace was multiplied by each farmer with the usual population size. Eighty plants from the initial population, the in situ and the two ex situ multiplications were individually tested using 26 microsatellite markers. Most of the genetic parameters showed a consistent decline in the ex situ populations compared with the in situ population, with a notable loss of less frequent alleles. The differentiation among the farmer subpopulations increased when the multiplication took place outside of the adaptation area. Although 120 plants were multiplied in each ex situ cycle, a bottleneck effect was present. In addition, tests for neutrality detected three loci that are involved in pathogen response and are potentially under selective effects. The diversity conservation and the management practices of autogamous landrace crops are discussed.     

Genetic diversity in the US ex situ populations of the endangered Puerto Rican Boa,Chilabothrus inornatus

The Puerto Rican Boa (Chilabothrus inornatus) was placed on the US Endangered Species List in 1970. Progress has been made since to clarify the recovery status of this species, though the design of a new recovery plan must include information regarding genetic variation within and among populations of this species. While measures of genetic diversity in wild populations of this species are finally becoming available, relative genetic diversity represented in ex situ populations is unknown, which hampers efforts to develop an ex situ species management plan. Here, we provide an analysis of genetic diversity in US public and private collections (zoos and breeders) using mitochondrial sequence data and five highly polymorphic nuclear microsatellite loci. We analyzed 50 boas from the US ex situ population and determined overall genetic diversity and relatedness among these individuals. We then compared these data to mitochondrial and microsatellite data obtained from 176 individuals from wild populations across the native range of the species. We found little inbreeding and a large amount of retained genetic diversity in the US ex situ population of C. inornatus relative to wild populations. Genetic diversity in the ex situ population is similar to that found in wild populations. Ours is only the second explicit attempt to characterize genetic diversity at the molecular level in ex situ populations of boid snakes. We anticipate that these results will inform current breeding strategies as well as offer additional information that will facilitate the continuation of ex situ conservation breeding or management in boas.