Decline In Genetic Diversity Research Articles

Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models.

Simple SummaryDue to continuous levels of human–wildlife conflict, habitat loss and fragmentation, the establishment of protected and enclosed reserves constitute a solid foundation for the long-term survival of threatened species. Because species living in enclosed systems often behave differently compared to their free-roaming counterparts, research is forming an important and essential tool to understand their ecology and behavior. For a population to be sustainable in a closed, fenced system, effective conservation and management strategies need to be developed on the basis of robust population estimates. We found that the study area, a protected nature reserve, is harbouring the highest leopard density in Namibia to date, highlighting that small, enclosed reserves can play a vital role for the survival of threatened species in the future. The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km2, the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.

A domestication history of dynamic adaptation and genomic deterioration in Sorghum.

The evolution of domesticated cereals was a complex interaction of shifting selection pressures and repeated episodes of introgression. Genomes of archaeological crops have the potential to reveal these dynamics without being obscured by recent breeding or introgression. We report a temporal series of archaeogenomes of the crop sorghum (Sorghum bicolor) from a single locality in Egyptian Nubia. These data indicate no evidence for the effects of a domestication bottleneck, but instead reveal a steady decline in genetic diversity over time coupled with an accumulating mutation load. Dynamic selection pressures acted sequentially to shape architectural and nutritional domestication traits and to facilitate adaptation to the local environment. Later introgression between sorghum races allowed the exchange of adaptive traits and achieved mutual genomic rescue through an ameliorated mutation load. These results reveal a model of domestication in which genomic adaptation and deterioration were not focused on the initial stages of domestication but occurred throughout the history of cultivation.

Response of xerophytic plants to glacial cycles in southern South America.

Quaternary glaciations strongly affected the distribution of species from arid and semi-arid environments, as temperature drops were accompanied by strong fluctuations in rainfall. In this study, we examined the response of xerophytic species to glacial cycles, determining the genetic patterns and climatic niche of Echinopsis chiloensis var. chiloensis, an endemic columnar cactus of arid and semi-arid regions of Chile. We analysed 11 polymorphic microsatellites for 130 individuals from 13 populations distributed across the entire distribution of the species. We examined genetic diversity and structure, identified possible patterns of isolation by distance (IBD) and tested two competing population history scenarios using Approximate Bayesian Computation. The first scenario assumes a constant population size while the second includes a bottleneck in the southern population. The latter scenario assumed that the southernmost populations experienced a strong contraction during glaciation, followed by a postglacial expansion; by contrast, the area of the northernmost populations remained as a stable refugium. We also used ecological niche modelling (ENM) to evaluate the location and extension of suitable areas during the Last Glacial Maximum (LGM) and the mid-Holocene. We found a decline in genetic diversity towards high latitudes and a significant IBD pattern that together with ENM predictions suggest that E. chiloensis var. chiloensis experienced range contraction northwards during wet-cold conditions of the LGM, followed by expansion during aridification of the mid-Holocene. In addition to IBD, we detected the presence of a strong barrier to gene flow at 32°30'S, which according to coalescence analysis occurred 44 kyr BP. The resulting genetic clusters differed in realized climatic niche, particularly in the variables related to precipitation. Our results suggest that the cactus E. chiloensis var. chiloensis experienced range contraction and fragmentation during the wet-cold conditions of the LGM, which may have facilitated ecological differentiation between northern and southern populations, promoting incipient speciation.

Temporal Patterns of Genetic Diversity in an Imperiled Population of the Eastern Massasauga Rattlesnake (Sistrurus catenatus)

The Eastern Massasauga (Sistrurus catenatus) is a small, grassland-dependent rattlesnake species declining throughout its native range, and is thus a species of high conservation priority. In Illinois, only a single population remains of a once widespread distribution. We documented genetic diversity in this population over a ten-year period and assessed levels of heterozygosity, allelic diversity, inbreeding (FIS), and effective population size (Ne). Neither heterozygosity nor levels of inbreeding differed significantly among periods. We identified 21 alleles that occurred in a single time period, some of which may have been lost from the population given our estimated detection probability of 93%. Effective population size (Ne) was numerically small and showed a decreasing trend through time. Despite small population size and a lack of connectivity, there was no significant decline in genetic diversity over the ten-year study. Aspects of life history, coupled with a preference for a historically patchy ...

Examining the interglacial high-elevation refugia scenario in East Asian subtropical mountain systems with the frog species Leptobrachium liui.

The effects of Quaternary climatic oscillations on the distributions of organisms in different parts of the world are not equally well understood, limiting the ability to understand the determinants of biodiversity. Compared with the mountain regions in southern Europe and southwestern North America, such effects on high‐elevation species in the East Asian subtropical mountain systems located in southern and southeastern China have seldom been addressed. In this study, using Leptobrachium liui (Megophryidae), we made one of the earliest attempts to examine the interglacial high‐elevation refugia scenario in these Asian mountains. Based on our current understanding of the study system, we formulated a hypothesis that these frogs of western origin were distributed more widely and continuously during glacial phases, allowing eastward dispersal, and that they are currently isolated in interglacial refugia at higher elevations. Microsatellite data and mitochondrial and nuclear sequence data were obtained with extensive sampling followed by the synthesis of phylogeographic and population genetic analyses and modeling of the species distribution. The analyses revealed a sequential eastward divergence of microsatellite clusters and gene lineages accompanied by a decline in genetic diversity. Molecular dating estimates revealed divergence events in the Pleistocene, and a reduction in local populations was inferred to have occurred at a time comparable to the end of the last glacial. Strong genetic isolation by distance reflecting a more continuous historical distribution was detected. Furthermore, environmental niche models inferred a wide planar distribution during the last glacial maximum, providing further support for the hypothesis.

Decline of genetic diversity in ancient domestic stallions in Europe

Present-day domestic horses are immensely diverse in their maternally inherited mitochondrial DNA, yet they show very little variation on their paternally inherited Y chromosome. Although it has recently been shown that Y chromosomal diversity in domestic horses was higher at least until the Iron Age, when and why this diversity disappeared remain controversial questions. We genotyped 16 recently discovered Y chromosomal single-nucleotide polymorphisms in 96 ancient Eurasian stallions spanning the early domestication stages (Copper and Bronze Age) to the Middle Ages. Using this Y chromosomal time series, which covers nearly the entire history of horse domestication, we reveal how Y chromosomal diversity changed over time. Our results also show that the lack of multiple stallion lineages in the extant domestic population is caused by neither a founder effect nor random demographic effects but instead is the result of artificial selection-initially during the Iron Age by nomadic people from the Eurasian steppes and later during the Roman period. Moreover, the modern domestic haplotype probably derived from another, already advantageous, haplotype, most likely after the beginning of the domestication. In line with recent findings indicating that the Przewalski and domestic horse lineages remained connected by gene flow after they diverged about 45,000 years ago, we present evidence for Y chromosomal introgression of Przewalski horses into the gene pool of European domestic horses at least until medieval times.

The effects of group versus intensive housing on the retention of genetic diversity in insurance populations

BackgroundRetention of genetic diversity and demographic sustainability are the cornerstones of conservation breeding success. In theory, monogamous breeding with equal reproductive output will retain genetic diversity in insurance populations more effectively than group housing which allows mate choice or intrasexual competition. However, the ecological relevance of group housing to a species can outweigh the theoretical benefits of forced monogamy. Here we investigated the influence of different types of captive housing (group (mate choice) versus intensive (forced monogamy)) on reproductive success, litter size and genetic diversity in the endangered Tasmanian devil (Sarcophilus harrisii).ResultsFor male Tasmanian devils, the proportion of individuals that failed to reproduce was significantly greater in group (maximum 10 individuals) than intensive housing. This suggests greater genetic diversity is retained when devils are bred in intensive housing. For male devils, body weight predicted reproductive success in group housing, suggesting certain individuals are dominant due to a larger body size, leading to unequal genetic contribution. We then used simulation models to predict rates of decline in genetic diversity and inbreeding accumulation over time comparing group and intensive housing. When managed independently, empirically observed reproductive outputs were predicted to result in large accumulations in inbreeding and loss of gene diversity in both housing types, although these effects were greater in group housing. Transferring individuals between the housing facilities decreased inbreeding accumulation and increased gene diversity in both housing types highlighting the importance of managing independent zoo populations collectively.ConclusionsIf conservation programs wish to provide mate choice opportunities through group housing, the impact intrasexual competition will have on dominance and sequential reproductive opportunities needs to be understood prior to commencement. Group housing is becoming increasingly topical as it provides potential ecological benefits, may decrease mate incompatibilities and increase offspring fitness, however it can also result in the loss of genetic diversity in already genetically depauperate species.

Genome of the Tasmanian tiger provides insights into the evolution and demography of an extinct marsupial carnivore

The Tasmanian tiger or thylacine (Thylacinus cynocephalus) was the largest carnivorous Australian marsupial to survive into the modern era. Despite last sharing a common ancestor with the eutherian canids ~160 million years ago, their phenotypic resemblance is considered the most striking example of convergent evolution in mammals. The last known thylacine died in captivity in 1936 and many aspects of the evolutionary history of this unique marsupial apex predator remain unknown. Here we have sequenced the genome of a preserved thylacine pouch young specimen to clarify the phylogenetic position of the thylacine within the carnivorous marsupials, reconstruct its historical demography and examine the genetic basis of its convergence with canids. Retroposon insertion patterns placed the thylacine as the basal lineage in Dasyuromorphia and suggest incomplete lineage sorting in early dasyuromorphs. Demographic analysis indicated a long-term decline in genetic diversity starting well before the arrival of humans in Australia. In spite of their extraordinary phenotypic convergence, comparative genomic analyses demonstrated that amino acid homoplasies between the thylacine and canids are largely consistent with neutral evolution. Furthermore, the genes and pathways targeted by positive selection differ markedly between these species. Together, these findings support models of adaptive convergence driven primarily by cis-regulatory evolution.

Genetic Diversity of an Invasive Invertebrate in an Urban Environment, as Exemplified by the HarlequinLadybird HarmoniaAxyridis (Pallas, 1773)

Urbanised areas are capable of exerting a strong impact on the distribution of genetic diversity within populations of animals. Urban invertebrate species are currently either relicts from pre-urban ecosystems, or have immigrated during or following urbanisation. We analysed 10 microsatellite loci in 196 specimens of the harlequin ladybird (Harmonia axyridis), an invasive species in Poland sampled in three of the country's cities. Of Asiatic origin, this ladybird has been spreading through other continents, including Europe. Results showed that the Polish cities are being invaded by harlequin ladybirds that are uniform in terms of their genetic pool, with no significant genetic differentiation present between the urban populations investigated. Rapid spread and what are probably the large numbers of individuals colonising new areas allow this species to maintain high genetic diversity and avoid bottleneck effects. However, we suggest that urban populations differ in terms of genetic diversity. The highest genetic diversity characterises the most recently invaded area of Olsztyn in the north of Poland. Genetic data further suggest that this population could be still in an expansion phase. The earliest colonising population in Wroclaw exhibits signs of a Wahlund effect, suggesting that gene flow among local groups within this urban area could be disturbed or impaired. We conclude that, in the case of an urban population of the harlequin ladybird, successful colonisation is followed by the onset of a decline in genetic diversity, with isolation between local sampling sites appearing. Further studies are required, however, if this process is to be elucidated.

The genetic structure of the introduced house sparrow populations in Australia and New Zealand is consistent with historical descriptions of multiple introductions to each country

The house sparrow is one of the most widely introduced vertebrate species around the world, making it an important model species for the study of invasion ecology. Population genetic studies of these invasions provide important insights into colonisation processes and adaptive responses occurring during invasion. Here we use microsatellite data to infer the population structure and invasion history of the introduced house sparrow (Passer domesticus) in Australia and New Zealand. Our results identify stronger population structure within Australia in comparison to New Zealand and patterns are consistent with historical records of multiple introduction sites across both countries. Within the five population clusters identified in Australia, we find declines in genetic diversity as we move away from the reported introduction site within each cluster. This pattern is consistent with sequential founder events. Interestingly, an even stronger decline in genetic diversity is seen across Australia as we move away from the Melbourne introduction site; secondary historical reports suggest this site imported a large number of sparrows and was possible the source of a single range expansion across Australia. However, private allele numbers are highest in the north, away from Melbourne, which could be a result of drift increasing the frequency of rare alleles in areas of smaller population size or due to an independent introduction that seeded or augmented the northern population. This study highlights the difficulties of elucidating population dynamics in introduced species with complex introduction histories and suggests that a combination of historical and genetic data can be useful.

Genetic diversity within populations of an arctic–alpine species declines with decreasing latitude across the Northern Hemisphere

AbstractAimWe identified and evaluated general latitudinal trends in genetic diversity within populations of a widespread arctic–alpine plant, Dryas octopetala, to examine the applicability to this species of the dominant hypothesis that intraspecific genetic diversity is highest in the tropics and declines towards the poles.LocationThe circumpolar Arctic and northern temperate alpine ranges, with a focus on high altitude mountains at the species lowest latitudinal margin in the Japanese archipelago.MethodsWithin‐population genetic diversity was assessed using genotypes determined at nine microsatellite loci (n = 489), chloroplast DNA sequences (atpB‐rbcL and trnV‐ndhC spacers, n = 181) and a nuclear gene sequence (LEAFY, n = 173) of 18 populations, as well as a previously published amplified fragment length polymorphism dataset for 26 populations, across the distributional range of the species. The latitudinal pattern of intra‐population genetic diversity was modelled at hemispheric scale to discriminate linear latitudinal and quadratic central–marginal trends in genetic diversity. Population genetic structure was assessed by Bayesian clustering analyses.ResultsAt hemispheric scale, we identified two interacting effects: a general latitudinal decline in genetic diversity towards the equator and a central–marginal effect, whereby genetic diversity decreases towards the margins of a species’ range. This decrease was more marked in low‐latitude marginal populations than in high‐latitude marginal populations. Populations at the lowest latitudes in the Japanese archipelago showed the lowest level of genetic diversity but exhibited distinctive genetic variation.Main conclusionThe latitudinal decline in genetic diversity within populations of this arctic–alpine plant across its range was opposite to the commonly observed trend. A significant part of the equator‐ward latitudinal decline in genetic diversity in this arctic–alpine species may be attributable to a “sky island” effect, which played a greater role at low latitudes.

Environmental marginality and geographic range limits: a case study with Arabidopsis lyrata ssp. lyrata

Understanding the factors that govern the distribution of species is a central goal of evolutionary ecology. It is commonly assumed that geographic range limits reflect ecological niche limits and that species experience increasingly marginal conditions towards the edge of their ranges. Using spatial data and ecological niche models we tested these hypotheses in Arabidopsis lyrata. Specifically, we asked whether range limits coincide with predicted niche limits in this system and whether the suitability of sites declines towards the edge of the species’ range in North America. We further explored patterns of environmental change towards the edge of the range and asked whether genome‐wide patterns of genetic diversity decline with increasing peripherality and environmental marginality. Our results suggest that latitudinal range limits coincide with niche limits. Populations experienced increasingly marginal environments towards these limits – though patterns of environmental change were more complex than most theoretical models for range limits assume. Genomic diversity declined towards the edge of the species’ range and with increasing distance from the estimated centre of the species’ niche in environmental space, but not with the suitability of sites based on niche model predictions. Thus while latitudinal range limits in this system are broadly associated with niche limits, the link between environmental conditions and genetic diversity (and thus the adaptive potential of populations) is less clear.

Tracing the origin of the early wet-season Anopheles coluzzii in the Sahel.

In arid environments, the source of the malaria mosquito populations that re‐establish soon after first rains remains a puzzle and alternative explanations have been proposed. Using genetic data, we evaluated whether the early rainy season (RS) population of Anopheles coluzzii is descended from the preceding late RS generation at the same locality, consistent with dry season (DS) dormancy (aestivation), or from migrants from distant locations. Distinct predictions derived from these two hypotheses were assessed, based on variation in 738 SNPs in eleven A. coluzzii samples, including seven samples spanning 2 years in a Sahelian village. As predicted by the “local origin under aestivation hypothesis,” temporal samples from the late RS and those collected after the first rain of the following RS were clustered together, while larger genetic distances were found among samples spanning the RS. Likewise, multilocus genotype composition of samples from the end of the RS was similar across samples until the following RS, unlike samples that spanned the RS. Consistent with reproductive arrest during the DS, no genetic drift was detected between samples taken over that period, despite encompassing extreme population minima, whereas it was detected between samples spanning the RS. Accordingly, the variance in allele frequency increased with time over the RS, but not over the DS. However, not all the results agreed with aestivation. Large genetic distances separated samples taken a year apart, and during the first year, within‐sample genetic diversity declined and increased back during the late RS, suggesting a bottleneck followed by migration. The decline of genetic diversity followed by a mass distribution of insecticide‐treated nets was accompanied by a reduced mosquito density and a rise in the mutation conferring resistance to pyrethroids, indicating a bottleneck due to insecticidal selection. Overall, our results support aestivation in A. coluzzii during the DS that is accompanied by long‐distance migration in the late RS.

Partial support for the central-marginal hypothesis within a population: reduced genetic diversity but not increased differentiation at the range edge of an island endemic bird.

Large-scale population comparisons have contributed to our understanding of the evolution of geographic range limits and species boundaries, as well as the conservation value of populations at range margins. The central-marginal hypothesis (CMH) predicts a decline in genetic diversity and an increase in genetic differentiation toward the periphery of species' ranges due to spatial variation in genetic drift and gene flow. Empirical studies on a diverse array of taxa have demonstrated support for the CMH. However, nearly all such studies come from widely distributed species, and have not considered if the same processes can be scaled down to single populations. Here, we test the CMH on a species composed of a single population: the Island Scrub-Jay (Aphelocoma insularis), endemic to a 250 km2 island. We examined microsatellite data from a quarter of the total population and found that homozygosity increased toward the island's periphery. However, peripheral portions of the island did not exhibit higher genetic differentiation. Simulations revealed that highly localized dispersal and small total population size, but not spatial variation in population density, were critical for generating fine-scale variation in homozygosity. Collectively, these results demonstrate that microevolutionary processes driving spatial variation in genetic diversity among populations can also be important for generating spatial variation in genetic diversity within populations.

New hope for the Eastern barred bandicoot Perameles gunnii after 27 years of recovery effort

The Eastern barred bandicoot Perameles gunnii (mainland unnamed subspecies) is classified as ‘extinct in the wild’ and has been the focus of a 27 year captive‐breeding and recovery programme. To date, the programme has successfully prevented the complete loss of this species, through the use of captive insurance populations and predator‐barrier fences, but has not yet delivered recovery in the wild. The key threats to this bandicoot are habitat loss and introduced predators; both difficult to mitigate. An active multi‐agency Recovery Team operates to conserve the Eastern barred bandicoot, manage recovery actions, and promote awareness and advocacy. The captive‐breeding programme has produced 920 offspring, 551 of which have been released to free‐ranging sites. Despite a slight but steady decline in genetic diversity over the duration of the programme, there does not appear to have been a significant loss of genetic fitness in the population, based on breeding rates, litter size and longevity. Animals have been released at a total of nine sites, with Eastern barred bandicoots currently present and breeding at four fox‐free locations. An ambitious plan is under way to more than double the current population to over 2500 individuals across several large self‐sustaining populations. This plan includes assisted colonization to fox‐free islands outside the natural range of the bandicoot and trialling the use of guardian dogs to protect unfenced, free‐ranging populations. Implementation of this Recovery Plan over the next 4 years will involve an array of conservation partners, and aims to down list the conservation status of the species and secure its future in the wild.

Comparative assessment of the genetic variation in selectively bred generations from two geographic populations of ivory shell (Babylonia areolata )

Ivory shell, Babylonia areolata, is one of the commercially important mariculture species in southern China and South-East Asia. The selection programme for growth trait has been conducted since 2010 in two selected lines for three generations, namely the Hainan (H) and Thailand (T) selected lines. Ten polymorphic microsatellite loci were used to monitor changes in their genetic diversity and structure during the selection process. A relatively high level of overall genetic diversity was observed, while the number of microsatellite allele declined slightly in the mass selection lines. Comparative diversity estimates indicated greater genetic diversity in H line than T line. Moreover, a relatively weak but significant genetic differentiation was found in both of the selected generations. In addition, the higher genetic variation observed in H line is most likely caused by artificial selection while selection bias on a growth advantage for the T population. These findings suggest no significant decline of genetic diversity was observed in the presently selected lines and that a potential exists for genetic improvement and development for B. areolata.

Soil acidity under multiple land-uses: assessment of perceived causes and indicators, and nutrient dynamics in small-holders’ mixed-farming system of northwest Ethiopia

ABSTRACTKnowledge on farmers’ perspectives is of paramount importance in order to design appropriate agricultural research and development interventions attuned to local farming systems. A participatory rural appraisal was conducted in order to understand perceived causes and indicators of soil acidity under multiple land-uses in three Districts of northwest Ethiopia. Soil samples were also collected from five dominant land-uses. The samples were analysed for soil pH, exchangeable acidity and other physico-chemical properties. The result indicated that the pH(H2O) of most of the soils in the study sites were in a strongly acidic range (4.6–5.5). Gashena Akayita of the Banja District was the most acidic of all. Among the land-uses, eucalyptus fields were the most acidic followed by crop outfields and grazing lands in that order. At all the study sites, exchangeable Al was detected in soils having a pH of less than 5.0. Overall, the nutrient dynamics showed variation across land-uses and study sites. Farmers’ perceived causes of soil acidity included: soil erosion; contending use of fertility replenishing local resources; abandoning traditional fertility management practices and minimal use of external inputs. The farmers attributed the exclusive use of acid-forming inorganic fertilizers to exhaustion of the soil. Various land and soil characteristics, plant growth attributes, changes in genetic diversity were mentioned as indicators of soil acidity. Particularly, the farmers used prevalence of acidophilic weed species on crop fields and grazing lands as marker of strongly acidic soil. Farmers’ perceived causes and indicators were in agreement with scientific facts and can be utilized as input in designing sustainable acid soil management strategies. Decline in genetic diversity of the once widespread crop species and land races, and expansion of newly introduced soil acidity tolerant species, suggests the need to undertake rescue collections in these areas.

Genetic diversity patterns of the orchid Anacamptis pyramidalis at the edges of its distribution range

Populations at the margins of a species’ distribution range are often smaller and more spatially isolated compared to centrally located populations. Therefore, a decline in within-population genetic variation and increased differentiation among populations towards range edges is expected. The edge effect can be enhanced by historical range expansions following glaciations in populations located at high latitudes. We investigated the level and distribution of genetic variation between 17 populations (collected from six countries) of the terrestrial orchid Anacamptis pyramidalis, using AFLP markers. Our study revealed no decline in genetic diversity in disjunct populations in Estonia at the northern border of the distribution area of this species, nor in the populations located at the southern edge of the range, on the island of Cyprus. Similarly, edge populations were not more differentiated from each other than the central populations in Slovenia and in Spain. Our results suggest that the degree of genetic variation is determined by the size of populations rather than geographic location of this species and underlines the impact of long-distance gene flow on the maintenance of genetic diversity in connection with major range shifts in the past.

Continued decline in genetic diversity among wild cheetahs (Acinonyx jubatus) without further loss of semen quality

As a well-studied felid with limited genetic diversity, the cheetah (Acinonyx jubatus) has shaped much of the scientific debate surrounding inbreeding depression. The species survived a population bottleneck ~12,000years ago and was extirpated from >75% of its historical range in the last century. Modern cheetahs produce poor-quality semen, a presumed manifestation of inbreeding depression. Within Felidae, a positive association between genetic diversity and semen quality is well supported by pedigree data and inter-species comparisons. However, this relationship has never been examined among individual cheetahs. Furthermore, whether ongoing population declines are exacerbating inbreeding depression in wild or captive cheetah populations is unknown. Using 12 microsatellite markers, we evaluated the relationship between heterozygosity and reproductive traits among wild (n=54) and captive (n=43) male cheetahs born from 1976–2007. We tested the hypotheses that genetic diversity has declined over the last ~30years and is positively correlated with semen quality/breeding success in the cheetah. Findings revealed that genetic diversity has decreased in the wild, but not captive, population. Unexpectedly, heterozygosity was lower in proven versus unproven breeders and did not correlate with semen quality. A small proportion of all males (<10%) produced relatively high quality ejaculates, with sperm traits similar to those of non-inbred felid species. These data suggest a more complex relationship between inbreeding and male cheetah reproductive traits than previously appreciated. Intensive management of captive cheetahs appears to be minimizing inbreeding, whereas the continued erosion of genetic diversity in wild males is of conservation concern.

KERAGAMAN GENETIK CENDANA PADA TEGAKAN PENGHASIL BENIH DAN TEGAKAN REHABILITASI DI NUSA TENGGARA TIMUR BERDASARKAN PENANDA ISOZIM

This study aimed to determine the genetic diversity of sandalwood on seed production stand and rehabilitation stand in East Nusa Tenggara using isozyme genetic marker. The study was conducted using samples collected from three stands, i.e. Seed Production Area (APB) representing seed production stand, KHDTK rehabilitation stand and CSR rehabilitation stand representing rehabilitation stands. Samples of sandalwood juvenile leaves are taken randomly from each location. Sample materials taken were juvenile leaves collected randomly from each stand. There were 57 samples taken from APB, while each 25 samples were collected from rehabilitation stands of KHDTK and CSR. Isozymes analyses were carried out in the laboratory using three kinds of enzyme systems i.e Esterase (EST), Diaphorase (DIA) and Shikimate Dehydrogenase (SHD). The results showed that for genetic diversity within stands, the mean of polymorphic loci was 88.89%, with a mean number of alleles per locus 2.1667 and a mean of effective alleles 1.2103. The expected heterozygosity within stands (HS) was 0.1558, with the observed heterozygosity (HO) of 0.1402, while the mean index of fixation (FIS) was 0.1118. On genetic diversity among stands, DST, and GST values were 0.0090 and 0.0545 respectively, while total expected heterozygosity of the three stands (HT) was 0.1648. To anticipate sandalwood genetic diversity decline, it is essential to identify and record the remaining sandalwood populations, then conserve rare alleles either through in-situ or ex-situ conservation programs.