Fine scale population genetic structure of pumas in the Intermountain West

In this study, I examined the population genetic structure of subpopulations of pumas (Puma concolor) in Idaho and surrounding states. Patterns of genetic diversity, population structure, levels of inbreeding, and the relationship between genetic differentiation and dispersal distance within and between 15 subpopulations of pumas were compared. Spatial analyses revealed that the Snake River plain was an important barrier to movement between northern and southern regions of Idaho. In addition, subpopulations south of the Snake River plain exhibited lower levels of genetic diversity, higher levels of inbreeding, and a stronger pattern of isolation by distance relative to subpopulations north of the Snake River plain. Lower levels of diversity and restricted gene flow are likely the result of historically lower population sizes in conjunction with more recent changes in habitat use and available dispersal corridors for movement. The subdivision of puma populations north and south of the Snake River plain, along with the patterns of genetic diversity within regions, indicate that landscape features are affecting the population genetic structure of pumas in Idaho. These results indicate that information about the effects of landscape features on the distribution of genetic diversity should be considered when designing plans for the management and conservation of pumas.     

Patterns of nuclear and mitochondrial DNA variation in Iberian populations of <Emphasis Type="Italic">Emys orbicularis</Emphasis> (Emydidae): conservation implications

The European pond turtle (Emys orbicularis) is threatened and in decline in several regions of its natural range, due to habitat loss combined with population fragmentation. In this work, we have focused our efforts on studying the genetic diversity and structure of Iberian populations with a fine-scale sampling (254 turtles in 10 populations) and a representation from North Africa and Balearic island populations. Using both nuclear and mitochondrial markers (seven microsatellites, ∼1048 bp nDNA and ∼1500 bp mtDNA) we have carried out phylogenetic and demographic analyses. Our results show low values of genetic diversity at the mitochondrial level although our microsatellite dataset revealed relatively high levels of genetic variability with a latitudinal genetic trend decreasing from southern to northern populations. A moderate degree of genetic differentiation was estimated for Iberian populations (genetic distances, F _ST values and clusters in the Bayesian analysis). The results in this study combining mtDNA and nDNA, provide the most comprehensive population genetic data for E. orbicularis in the Iberian Peninsula. Our results suggest that Iberian populations within the Iberian–Moroccan lineage should be considered as a single subspecies with five management units, and emphasize the importance of habitat management rather than population reinforcement (i.e. captive breeding and reintroduction) in this long-lived species.     

Genetic Diversity and Divergence among Bighorn Sheep from Reintroduced Herds in Washington and Idaho

Bighorn sheep (Ovis canadensis) populations in the western United States have undergone widespread declines and extirpations since the late nineteenth century as a consequence of introduced diseases, competition with livestock, and unregulated hunting. Washington, Idaho, USA, and British Columbia, Canada were historically thought to be occupied by 2 bighorn lineages or subspecies: Rocky Mountain (O. c. canadensis) and California (O. c. californiana). The putative California lineage was completely extirpated in the United States, and reintroductions to reestablish populations were sourced directly or indirectly from a single region in southern British Columbia. Restoration efforts have attempted to maintain the diversity and divergence of these 2 lineages, sometimes referred to as subspecies although taxonomic classifications have changed over time. In this study we describe genetic variation in a subset of native and reintroduced herds of California and Rocky Mountain bighorn sheep. We examined genetic diversity and divergence between bighorn sheep herds using 15 microsatellite loci, including 4 loci linked to genes involved in immune function. We analyzed 504 samples from reintroduced herds in Washington (n = 10 California herds, n = 4 Rocky Mountain herds) and Idaho (n = 5 California), and source herds in Oregon (n = 1 Rocky Mountain) and British Columbia (n = 5 California, 1 Rocky Mountain). Genetic structure reflected known reintroduction history, and geographic proximity also was associated with decreased genetic divergence. Herds in Washington and Idaho sourced from California bighorn sheep were less genetically diverse than those sourced from Rocky Mountain herds. Also, levels of relatedness within and across California herds were higher than in Rocky Mountain herds and similar to what would be expected for full and half siblings. Lower diversity and higher relatedness among California herds is a concern for long-term fitness and likely related to past population bottlenecks, fewer source populations, and management history, such as entirely sourcing California herds from British Columbia. Genetic divergence of neutral loci between California and Rocky Mountain herds was greater than that of adaptive loci, potentially indicating that balancing selection has maintained similar genetic diversity across lineages in loci associated with immune and other adaptive functions. Thus, we recommend future reintroductions and augmentations should continue to use source populations from the appropriate California or Rocky Mountain lineage to avoid potential outbreeding depression and maintain possible adaptive differences. This could be accomplished by obtaining sheep from ≥1 source within the genetic lineage, while avoiding sourcing from admixed herds. Future work encompassing a broader geographic sampling of populations and a greater portion of the genome is necessary to better evaluate the degree to which contemporary divergence between lineages is associated with recent founder effects and genetic isolation or evolutionary adaptation. © 2021 The Wildlife Society     

Significant genetic admixture after reintroduction of peregrine falcon (<Emphasis Type="Italic">Falco peregrinus</Emphasis>) in Southern Scandinavia

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.     

Evaluation of a remnant lake sturgeon population’s utility as a source for reintroductions in the Ohio River system

The selection of an appropriate source population may be crucial to the long-term success of reintroduction programs. Appropriate source populations often are those that originate from the same genetic lineage as native populations. However, source populations also should exhibit high levels of genetic diversity to maximize their capacity to adapt to variable environmental conditions. Finally, it is preferable if source populations are genetically representative of historical lineages with little or no contamination from non-native or domesticated stocks. Here, we use nuclear (microsatellite) and cytoplasmic (mitochondrial control region) markers to assess the genetic suitability of a potential source population inhabiting the White River in Indiana: the last extant lake sturgeon population in the Ohio River drainage. The White River population exhibited slightly lower levels of genetic diversity than other lake sturgeon populations. However, the population’s two private microsatellite alleles and three private haplotypes suggest a unique evolutionary trajectory. Population assignment tests revealed only two putative migrants in the White River, indicating the population has almost completely maintained its genetic integrity. Additionally, pairwise F _ST estimates indicated significant levels of genetic divergence between the White River and seven additional lake sturgeon populations, suggesting its genetic distinctiveness. These data indicate that the White River population may be the most suitable source population for future lake sturgeon reintroductions throughout the Ohio River drainage. Furthermore, the White River population appears to be a reservoir of unique genetic information and reintroduction may be a necessary strategy to ensure the persistence of this important genetic lineage.     

Characterisation of microsatellite loci in the subtidal habitat-forming alga, Phyllospora comosa (Phaeophyceae, Fucales)

Habitat-forming macroalgae play a central role in the ecology of temperate reefs worldwide but there exists a critical lack of knowledge about important processes such as dispersal and gene flow. Understanding dispersal and gene flow of habitat-forming seaweeds is particularly pertinent given that loss of habitat-forming algae is an increasingly prevalent problem worldwide. Here, we develop 10 microsatellite markers for the monotypic Phyllospora comosa, an important habitat-forming macroalga that has undergone massive declines on urbanised coastlines of Sydney, Australia. We characterise population genetic diversity and structure and estimate levels of dispersal and gene flow between the geographically isolated northern and southern populations in this subtidal macroalga.     

Genetic structure of muskrat (Ondatra zibethicus) and its concordance with taxonomy in North America

Extrinsic factors such as physical barriers play an important role in shaping population genetic structure. A reduction in gene flow leading to population structuring may ultimately lead to population divergence. These divergent populations are often considered subspecies. Because genetic differentiation may represent differences between subspecies, patterns of genetic structure should reflect subspecies groupings. In this study, we examine the contemporary population genetic structure of muskrat (n = 331) and assess the relevance of 4 geographically distinct subspecies designations across northern North America using 9 microsatellite loci. We predicted that patterns of gene flow and genetic structure would reflect the described subspecies. We found evidence of genetic differentiation between western and eastern regions, and muskrats from Newfoundland (NF) showed significantly lower genetic diversity than central regions. A strong isolation by distance pattern was also detected within the eastern cluster. Our results did not differentiate Ondatra zibethicus spatulus (northwest) from O. z. albus (central), but they suggest a distinction between O. z. obscurus (NF) and O. z. zibethicus (east). This study highlights the need for more phylogenetic studies in order to better understand intraspecific divergence and the genetic characterization of subspecies.     

Microsatellite genetic variation of Asian populations of Dolly Varden char

Genetic variation at eight microsatellite loci was examined in 21 populations of Dolly Varden charrs, Salvelinus malma, representing five geographical regions (Kamchatka Peninsula, Sea of Okhotsk coast, Sea of Japan coast, Sakhalin Island, and Kuril islands). Hierarchical analysis of molecular variance showed that 11% (58% in terms of R-statistics) of the variation was distributed among of northern subspecies of Dolly Varden, Salvelinus malma malma and southern Asian Dolly Varden, S. m. krascheninnikovi while similar values were attributed to the among-regional level within northern Dolly Varden 9% (7%) and southern Asian Dolly Varden 11% (14%). Permutation-based tests indicated a mutational component to genetic differentiation based on allelic size variance and suggested that divergence of the two subspecies had occurred at least 3,000 generations ago. On large spatial scales (within the Asian range of the species), populations clustered according to their geographical location. On smaller scales (within regions and subregions) correlation between genetic and geographic distances was not significant. Northern Dolly Varden has higher allelic diversity and more private alleles than southern subspecies, this probably indicating differences in demographic history.     

Microsatellite and mitochondrial DNA variation defines island genetic reservoirs for reintroductions of an endangered Australian marsupial, <Emphasis Type="Italic">Perameles bougainville</Emphasis>

Natural populations of the endangered western barred bandicoot (Perameles bougainville) now exist on only two islands in Shark Bay, Western Australia. Our aim was to investigate genetic diversity in natural, reintroduced, and captive populations of the bandicoots and to assess the extent of divergence between the populations. The contemporary isolation of the natural populations has resulted in heterogeneity of allele frequency between the islands, which has acted to maintain a higher combined diversity than would be expected from either population on its own. These findings highlight how remnant island populations can act as genetic reservoirs to maximize diversity for reintroductions into a species former range. Although diversity is high between island populations, diversity within populations, based on six microsatellite loci, are amongst the lowest ever recorded for populations of marsupials. The mtDNA sequence data indicate that the two remaining natural populations show only minor divergence from each other, with the five haplotypes separated by just single base pairs. The reintroduced population and captive colonies show evidence for the loss of diversity related to genetic drift operating on small isolated populations.     

A genetic comparison of two alleged subspecies of Philippine cynomolgus macaques

Two subspecies of cynomolgus macaques (Macaca fascicularis) are alleged to co‐exist in the Philippines, M. f. philippensis in the north and M. f. fascicularis in the south. However, genetic differences between the cynomolgus macaques in the two regions have never been studied to document the propriety of their subspecies status. We genotyped samples of cynomolgus macaques from Batangas in southwestern Luzon and Zamboanga in southwestern Mindanao for 15 short tandem repeat (STR) loci and sequenced an 835 bp fragment of the mtDNA of these animals. The STR genotypes were compared with those of cynomolgus macaques from southern Sumatra, Singapore, Mauritius and Cambodia, and the mtDNA sequences of both Philippine populations were compared with those of cynomolgus macaques from southern Sumatra, Indonesia and Sarawak, Malaysia. We conducted STRUCTURE and PCA analyses based on the STRs and constructed a median joining network based on the mtDNA sequences. The Philippine population from Batangas exhibited much less genetic diversity and greater genetic divergence from all other populations, including the Philippine population from Zamboanga. Sequences from both Batangas and Zamboanga were most closely related to two different mtDNA haplotypes from Sarawak from which they are apparently derived. Those from Zamboanga were more recently derived than those from Batangas, consistent with their later arrival in the Philippines. However, clustering analyses do not support a sufficient genetic distinction of cynomolgus macaques from Batangas from other regional populations assigned to subspecies M. f. fascicularis to warrant the subspecies distinction M. f. philippensis. Am J Phys Anthropol 155:136–148, 2014. © 2014 Wiley Periodicals, Inc.     

Genetic isolation in an endemic African habitat specialist

The Chestnut‐banded Plover Charadrius pallidus is a Near‐Threatened shorebird species endemic to mainland Africa. We examined levels of genetic differentiation between its two morphologically and geographically distinct subspecies, C. p. pallidus in southern Africa (population size 11 000–16 000) and C. p. venustus in eastern Africa (population size 6500). In contrast to other plover species that maintain genetic connectivity over thousands of kilometres across continental Africa, we found profound genetic differences between remote sampling sites. Phylogenetic network analysis based on four nuclear and two mitochondrial gene regions, and population genetic structure analyses based on 11 microsatellite loci, indicated strong genetic divergence, with 2.36% mitochondrial sequence divergence between individuals sampled in Namibia (southern Africa) and those of Kenya and Tanzania (eastern Africa). This distinction between southern and eastern African populations was also supported by highly distinct genetic clusters based on microsatellite markers (global F_ST = 0.309,  = 0.510, D = 0.182). Behavioural factors that may promote genetic differentiation in this species include habitat specialization, monogamous mating behaviour and sedentariness. Reliance on an extremely small number of saline lakes for breeding and limited dispersal between populations are likely to promote reproductive and genetic isolation between eastern and southern Africa. We suggest that the two Chestnut‐banded Plover subspecies may warrant elevation to full species status. To assess this distinction fully, additional sample collection will be needed, with analysis of genetic and phenotypic traits from across the species’ entire breeding range.     

Genetic variation in natural and translocated populations of the endangered Delmarva fox squirrel (Sciurus niger cinereus)

The Delmarva fox squirrel, Sciurus niger cinereus, is a federally listed endangered subspecies whose range has been reduced by 90%. In an attempt to increase both population size and range, translocation sites were established beginning in the 1960's by moving squirrels from the natural range to sites outside the current range. Although translocations have served as the primary component of the DFS recovery program, there has been very little post-release examination of the genetics of the translocation sites. In this study, we developed ten microsatellite loci, screened the three polymorphic loci, and sequenced a 330 bp fragment of the mitochondrial control region in order to assess levels of genetic variation in natural and translocated regions of Delmarva fox squirrels and to compare them to Southeastern fox squirrels (S. n. niger). Although we found low levels of microsatellite polymorphism, there were no differences in heterozygosity between natural and translocated regions, or between Delmarva and Southeastern fox squirrels. We found high levels of polymorphism in the mitochondrial control region. Our patterns of haplotype diversity suggest incomplete lineage sorting of the two subspecies. In general, our data suggest that the current levels of genetic variation in the translocated sites are representative of those found in the natural population, and we encourage the continued use of translocations as a major component of Delmarva fox squirrel recovery. This revised version was published online in July 2006 with corrections to the Cover Date.     

Disrupted phylogeographical microsatellite and chloroplast DNA patterns indicate a vicariance rather than long‐distance dispersal origin for the disjunct distribution of the Chilean endemic Dioscorea biloba (Dioscoreaceae) around the Atacama Desert

Aim The Chilean endemic Dioscorea biloba (Dioscoreaceae) is a dioecious geophyte that shows a remarkable 600 km north–south disjunction in the peripheral arid area of the Atacama Desert. Its restricted present‐day distribution and probable Neogene origin indicate that its populations have a history linked to that of the Atacama Desert, making this an ideal model species with which to investigate the biogeography of the region. Location Chile, Atacama Desert and peripheral arid area. Methods Two hundred and seventy‐five individuals from nine populations were genotyped for seven nuclear microsatellite loci, and plastid trnL–F and trnT–L sequences were obtained for a representative subset of these. Analyses included the estimation of genetic diversity and population structure through clustering, Bayesian and analysis of molecular variance analyses, and statistical parsimony networks of chloroplast haplotypes. Isolation by distance was tested against alternative dispersal hypotheses. Results Microsatellite markers revealed moderate to high levels of genetic diversity within populations, with those from the southern Limarí Valley showing the highest values and northern populations showing less exclusive alleles. Bayesian analysis of microsatellite data identified three genetic groups that corresponded to geographical ranges. Chloroplast phylogeography revealed no haplotypes shared between northern and southern ranges, and little haplotype sharing between the two neighbouring southern valleys. Dispersal models suggested the presence of extinct hypothetical populations between the southern and northern ranges. Main conclusions Our results are consistent with prolonged isolation of the northern and southern groups, mediated by the life‐history traits of the species. Significant isolation was revealed at both large and moderate distances as gene flow was not evident even between neighbouring valleys. Bayesian analyses of microsatellite and chloroplast haplotype diversity identified the southern area of Limarí as the probable area of origin of the species. Our data do not support recent dispersal of D. biloba from the southern range into Antofagasta, but indicate the fragmentation of an earlier wider range, concomitant with the Pliocene–Pleistocene climatic oscillations, with subsequent extinctions of the Atacama Desert populations and the divergence of the peripheral ones as a consequence of genetic drift.     

Population genetic structure of the endangered crayfish Austropotamobius pallipes in France based on microsatellite variation: biogeographical inferences and conservation implications

1. One important goal in conservation biology is to characterise evolutionary lineages within endangered species before management decisions are taken. Here, we assess population differentiation in the freshwater crayfish Austropotamobius pallipes, an endangered species endemic to western Europe and provide valuable information for the conservation of French populations. 2. Analysis of five microsatellite loci in 44 populations revealed very different within population levels of genetic diversity (0.000 < H₀ < 0.564). Two groups, corresponding to northern and southern French populations, showed a high degree of genetic differentiation in both allele frequencies and allele sizes. Comparison of these results with previous studies of A. pallipes strongly suggests that the divergence between northern and southern populations could have occurred during the last glaciation period of the Pleistocene from one Atlantic and one Mediterranean refuge. 3. Evidence for genetic admixture between these two lineages was revealed by correspondence analyses in southern populations, probably as the result of artificial translocations. 4. French populations appeared significantly differentiated among the different river drainages and were highly structured within rivers. The impact of population size, population bottlenecks and founder events on the population genetic differentiation are discussed. 5. Based on these results, we propose the designation of two evolutionarily significant units for A. pallipes in France. Our data also support the maintenance of separate demographic management strategies for crayfish inhabiting different river systems. However, genetic analyses will have to be combined with demographic and ecological data for sustainable conservation programmes.     

Weak large‐scale population genetic structure in a philopatric seabird,the European Shag Phalacrocorax aristotelis

Quantifying population genetic structure is fundamental to testing hypotheses regarding gene flow, population divergence and dynamics across large spatial scales. In species with highly mobile life‐history stages, where it is unclear whether such movements translate into effective dispersal among discrete philopatric breeding populations, this approach can be particularly effective. We used seven nuclear microsatellite loci and mitochondrial DNA (ND2) markers to quantify population genetic structure and variation across 20 populations (447 individuals) of one such species, the European Shag, spanning a large geographical range. Despite high breeding philopatry, rare cross‐sea movements and recognized subspecies, population genetic structure was weak across both microsatellites and mitochondrial markers. Furthermore, although isolation‐by‐distance was detected, microsatellite variation provided no evidence that open sea formed a complete barrier to effective dispersal. These data suggest that occasional long‐distance, cross‐sea movements translate into gene flow across a large spatial scale. Historical factors may also have shaped contemporary genetic structure: cluster analyses of microsatellite data identified three groups, comprising colonies at southern, mid‐ and northern latitudes, and similar structure was observed at mitochondrial loci. Only one private mitochondrial haplotype was found among subspecies, suggesting that this current taxonomic subdivision may not be mirrored by genetic isolation.     

Threatened populations of the Australian squirrel glider (Petaurus norfolcensis) show evidence of evolutionary distinctiveness on a Late Pleistocene timescale

The squirrel glider Petaurus norfolcensis occurs across a broad Australian latitudinal range that includes gaps in distribution and potential biogeographic barriers, creating the potential for evolution of distinct entities within this species. Because of the species’ threatened status in the southern part of its range, we tested for the presence of geographically based independent evolutionary units among gliders sampled from southern, and northern coastal populations, using sequences of mitochondrial cytochrome b DNA (mtDNA) and a set of five nuclear microsatellites in 258 individuals. Our analyses suggest that an initial northward colonisation in the early- to mid-Pleistocene was followed by isolation by distance and, eventually, divergence between the sampled coastal and southern populations in the mid- to late-Pleistocene. We propose that the previously large and diverse southern populations have declined coincidentally with the replacement of wet forests by open sclerophyll woodlands during the preceding few million years. By contrast coastal populations further north appear to have been expanding and at present have an effective population size several times greater than southern populations. These results suggest that the two forms are on different evolutionary trajectories and should be treated separately for conservation purposes. It is highly desirable that loss of southern populations be prevented to maintain the unique genetic diversity accumulated over a considerable evolutionary timescale.     

Subspecific relationships and genetic structure in the spotted owl

Hierarchical genetic structure was examined in the three geographically-defined subspecies of spotted owl (Strix occidentalis) to define relationships among subspecies and quantify variation within and among regional and local populations. Sequences (522 bp) from domains I and II of the mitochondrial control region were analyzed for 213 individuals from 30 local breeding areas. Results confirmed significant differences between northern spotted owls and the other traditional geographically defined subspecies but did not provide support for subspecific level differences between California and Mexican spotted owls. Divergence times among subspecies estimated with a 936 bp portion of the cytochrome b gene dated Northern and California/Mexican spotted owl divergence time to 115,000–125,000 years ago, whereas California/Mexican spotted owl divergence was estimated at 15,000 years ago. Nested clade analyses indicated an association between California spotted owl and Mexican spotted owl haplotypes, implying historical contact between the two groups. Results also identified a number of individuals geographically classified as northern spotted owls (S. o. caurina) that contained haplotypes identified as California spotted owls (S. o. caurina). Among all northern spotted owls sampled (n=131), 12.9% contained California spotted owl haplotypes. In the Klamath region, which is the contact zone between the two subspecies, 20.3% (n=59) of owls were classified as California spotted owls. The Klamath region is a zone of hybridization and speciation for many other taxa as well. Analyses of population structure indicated gene flow among regions within geographically defined subspecies although there was significant differentiation among northern and southern regions of Mexican spotted owls. Among all areas examined, genetic diversity was not significantly reduced except in California spotted owls where the southern region consists of one haplotype. Our results indicate a stable contact zone between northern and California spotted owls, maintaining distinct subspecific haplotypes within their traditional ranges. This supports recovery efforts based on the traditional subspecies designation for the northern spotted owl. Further, although little variation was found between California and Mexican spotted owls, we suggest they should be managed separately because of current isolation between groups.     

Intraspecific Phylogeography of Red Squirrels (Tamiasciurus hudsonicus) in the Central Rocky Mountain Region of North America

We used variation in a portion of the mitochondrial DNA control region to examine phylogeography of Tamiasciurus hudsonicus, a boreal-adapted small mammal in the central Rocky Mountain region. AMOVA revealed that 65.66% of genetic diversity was attributable to variation within populations, 16.93% to variation among populations on different mountain ranges, and 17.41% to variation among populations within mountain ranges. Nested clade analysis revealed two major clades that likely diverged in allopatry during the Pleistocene: a southern clade from southern Colorado and a northern clade comprising northern Colorado, Wyoming, eastern Utah, and eastern Idaho. Historically restricted gene flow as a result of geographic barriers was indicated between populations on opposite sides of the Green River and Wyoming Basin and among populations in eastern Wyoming. In some instances genetic structure indicated isolation by distance.     

Population genetics and conservation of the threatened southeastern beach mouse (Peromyscus polionotus niveiventris): subspecies and evolutionary units

We investigated genetic diversity within the southeastern beach mouse (SEBM-Peromyscus polionotus niveiventris) and also tested the hypothesis that the subspecies recognition of P.p. niveiventris, based on size and color differences, is congruent with this taxon representing a discrete evolutionary lineage. We used ten polymorphic microsatellite loci and mitochondrial cytochrome-b gene DNA sequences to investigate genetic diversity and population structure within the SEBM, and to determine the level of divergence between the SEBM and the nearest known inland subspecies of the oldfield mouse (Peromyscus polionotus rhoadsi). Moderate genetic distances were observed between the SEBM and the inland oldfield mouse based on microsatellite data, with F _ST values ranging from 0.11 to 0.22 between these taxa. Additionally, mitochondrial DNA haplotypes of the SEBM formed a distinct monophyletic group relative to haplotypes sampled from P. p. rhoadsi. Based on previous estimates of rates of mitochondrial DNA evolution in rodents, we inferred that Pleistocene sea-level fluctuations are likely responsible for the historical isolation of the SEBM lineage from mainland P. polionotus. Our data demonstrate the genetic distinctiveness of the SEBM, justifying the current subspecies designation for the SEBM and its continued protection under the United States Endangered Species Act. We classify the Cape Canaveral and Smyrna Dunes Park populations of SEBM as a single evolutionary significant unit. The two known extant allopatric populations of the SEBM showed some differentiation in microsatellite frequencies and were moderately reciprocally distinguishable based on assignment to distinct genetic clusters by a Bayesian admixture procedure. These results justify the classification of these two extant SEBM populations as distinct management units that should be independent targets of management and conservation attention.     

芦鹀种群中的文化、遗传和形态进化的同时比较

我们比较了芦 (Emberizaschoeniclus)两个亚种组 ,即北部的薄喙亚种组和南部的厚喙亚种组的 10个种群中的文化、遗传和形态变异。使用了四个不同的变异标记物 ,其中两个用来测量文化分化 ,一个用来测量遗传分化 ,即微卫星等位基因的频次 ,一个用来测量种群的形态分化 ,即喙的高度。将遗传分化作为进化时间的尺度 ,我们计算了亚种组间和组内分化指标与所估计的进化率之间的相关性 ,发现只有文化定量指标和遗传分化与种群的形态分化相关 ,而两个文化分化指标之间没有关系 ,文化分化与遗传分化之间也没有关系。使用文化 -定量分化指标 ,发现亚种组间的文化进化率高于亚种内的文化进化率 ,提示鸣唱在防止杂交方面只有微弱的、也许是次要的作用。鸣唱定量特征的变异与微卫星频次相同 ,实际上在自然界中更可能是遗传决定的 ,这可以解释由于分析两个文化变异指标所得出的结果的不一致性。鸣唱的声学特性可能由于栖息地的差异或形态上的限制而发生了演变 ,而文化传播单位 (Meme)的特性可能由于学习鸣唱和文化传播而受到了影响