DNA Control Region Sequences Research Articles

Evaluation of the Impact of Population Management on the Genetic Parameters of Selected Spiral-Horned Antelopes.

The rapid loss of biodiversity and the associated reduction and fragmentation of habitats means that ex situ populations have become an important part of species conservation. These populations, which are often established from a small number of founders, require careful management to avoid the negative effects of genetic drift and inbreeding. Although the inclusion of molecular data is recommended, their availability for captive breeding management remains limited. The aim of this study was to evaluate the relationship between the levels of genetic diversity in six spiral-horned antelope taxa bred under human care and their respective management strategies, conservation status, demography, and geographic origin, using 10 nuclear DNA microsatellite loci and mitochondrial control region DNA sequences. Our findings include associations between genetic diversity and management intensity but also with the diversity and contribution of wild populations to captive founders, with some populations apparently composed of animals from divergent wild lineages elevating captive genetic diversity. When population sizes are large, the potential advantages of maximizing genetic diversity in widely outcrossed populations may need careful consideration with respect to the potential disruption of adaptive diversity. Genetic data serve as a robust tool for managing captive populations, yet their interpretation necessitates a comprehensive understanding of species biology and history.

Mitochondrial Genetic Diversity, Population Structure and Detection of Antillean and Amazonian Manatees in Colombia: New Areas and New Techniques.

The Antillean manatee (Trichechus manatus) and the Amazonian manatee (Trichechus inunguis) are distributed in rivers in the Caribbean and Amazonian region of Colombia respectively. For 30 years, genetic information has been obtained from these populations in order to inform conservation programs for these endangered species and decide on the location to release them back to the wild. However, in previous studies, samples from rivers in some areas of the country were not included, given the difficulties to access these regions due to either logistic or safety issues. In this study, we analyzed mitochondrial DNA (mtDNA) control region (CR) sequences of from samples of T. manatus (n = 37) and T. inunguis (n = 4) (410 and 361 bp, respectively), obtained in new and previously unexplored rivers and bays in the country, including Santa Marta, Urabá Gulf, Ayapel Marsh (San Jorge River Basin), Meta River and Magdalena Medio and the low Magdalena River (Cesar Province and Canal del Dique) as well as additional samples from Puerto Nariño in the Colombian Amazon. Our results included the discovery of two newly described mtDNA CR haplotypes for T. manatus. In addition, we confirmed significant population differentiation at the mitochondrial level between the Magdalena and Sinú rivers and differentiation among areas of the same river, including the middle and low Magdalena River. This differentiation may be related to anthropic changes in the river since construction of the Canal del Dique in the XVI century. We also tested environmental DNA sampling and analyses techniques to evaluate its potential use for manatee detection and monitoring in bodies of water in Colombia, in order to evaluate new areas for future manatee conservation initiatives. We emphasize the need to continue using genetic information to provide evidence on the potential best locations to undertake animal release to prevent outbreeding depression.

Genetic integrity and individual identification-based population size estimate of the endangered long-tailed goral, Naemorhedus caudatus from Seoraksan National Park in South Korea, based on a non-invasive genetic approach

ABSTRACT The long-tailed goral (also called the Amur goral) Naemorhedus caudatus (subfamily Caprinae), a vulnerable and protected species designated by IUCN and CITES, has sharply been declining in the population size and is now becoming critically endangered in South Korea. This species has been conserved as a natural monument by the Korean Cultural Heritage Administration since 1968. In this study, using 78 fecal DNA samples with a non-invasive genetic approach, we assessed the genetic integrity and individual identification-based population size for the goral population from Seoraksan National Park representing the largest wild population in Korea. Using the successfully isolated 38 fecal DNA, phylogeographic and population genetic analyses were performed with mitochondrial DNA control region (CR) sequences and nine microsatellite loci. We found seven CR haplotypes, of which five were unique to the Seoraksan population, considering previously determined haplotypes in Korean populations. The Seoraksan population showed higher haplotype diversity (0.777 ± 0.062) and mean number of alleles (4.67 ± 1.563) relative to southern populations in Korea reported from previous studies, with no signal of a population bottleneck. Microsatellite-based individual identification estimate based on probability of identity (PID) indicated a population size of ≥30 in this population. Altogether, we suggest that for future management efforts of this species in the Seoraksan National Park, conserving its genetic integrity as an ‘endemic’ lineage, and curbing a decrease in its number through mitigating habitat destruction might be key to secure the population for the long term.

Mitochondrial DNA control region variation in a population sample from Thailand

Mitochondrial DNA (mtDNA) control region sequences from hair samples of 213 individuals from Thailand were analyzed using Sanger sequencing. A total of 170 different haplotypes were identified, of which 146 occurred only once (unique haplotypes). The dataset showed a random match probability of 0.87% and a haplotype diversity of 0.9960. The samples were assigned to 85 different haplogroups with B5a, F1a1a, and M being the most frequent ones. Pairwise FST-values between this and other Southeast and East Asian populations revealed significant but relatively low differences, indicating a close relation. Heteroplasmic positions were observed in 12.2% of hair samples confirming the frequent appearance of heteroplasmic positions in hairs. This dataset will complement existing data as an mtDNA reference for forensic investigations.

Long-term isolation at a low effective population size greatly reduced genetic diversity in Gulf of California fin whales

The Gulf of California, Mexico is home to many cetacean species, including a presumed resident population of fin whales, Balaenoptera physalus. Past studies reported very low levels of genetic diversity among Gulf of California fin whales and a significant level of genetic differentiation from con-specifics in the eastern North Pacific. The aim of the present study was to assess the degree and timing of the isolation of Gulf of California fin whales in a population genetic analysis of 18 nuclear microsatellite genotypes from 402 samples and 565 mitochondrial control region DNA sequences (including mitochondrial sequences retrieved from NCBI). The analyses revealed that the Gulf of California fin whale population was founded ~2.3 thousand years ago and has since remained at a low effective population size (~360) and isolated from the eastern North Pacific (Nem between 0.89–1.4). The low effective population size and high degree of isolation implied that Gulf of California fin whales are vulnerable to the negative effects of genetic drift, human-caused mortality and habitat change.

Kashmiris phylogenetic depictions through uniparental and biparental genetic markers.

In this study, the Kashmiri population was genetically screened for fifteen autosomal STRs, seventeen Y-chromosomal STRs and mitochondrial DNA control region SNPs. Autosomal STRs exhibited that D2S1338 was the most discriminatory locus with value of 0.963 whereas combine power of discrimination was 0.999999999999999. On the other hand, analysis of Y-chromosomal STRs generated 59 distinct haplotypes of which 52 were unique with haplotype diversity value of 0.99752. Mitochondrial D-loop analysis resulted that haplogroups M and U were found most prevalent with 25% each. Haplotypic data of Y-STRs was submitted to YHRD under accession number YA004153 whereas mitochondrial DNA control region (CR) sequences were submitted to EMPOP with accession number EMP00683.

Genetic homogeneity of the Pacific thread herring (Opisthonema libertate) (Günther, 1867) in the Eastern Pacific, inferred from mtDNA sequences

In the present study, the population genetic structure of the Pacific thread herring (Opisthonema libertate) was analyzed through mitochondrial DNA (mtDNA) control region sequences. Organisms were collected from June 2015 to July 2015 from four commercial landing sites (Bahia Magdalena, Guaymas and Mazatlan, Mexico, and Puntarenas, Costa Rica) and one artisanal sampling site (Puerto La Libertad, El Salvador). A total of 125 sequences were analyzed. High levels of haplotype (h = 0.990) and nucleotide (π = 0.030) diversity were found. Pairwise Φst comparisons indicated differences attributed mainly to the organisms from El Salvador. However, Bayesian inferences did not support the existence of different populations. The haplotype distribution between locations did not show a clear phylogeographic pattern. Mismatched distribution showed a unimodal pattern for the five sampled areas, indicative of sudden demographic expansion. These results were supported by Bayesian skyline plot. Our results do not support the hypothesis that the Pacific thread herring presents a population genetic structure. Future genetic comparisons should include a larger number of samples as well as more polymorphic molecular markers to further support our results.

Phylogeny and genetic structure of the goitered gazelle (Artiodactyla, Bovidae) in north-western China indicated by the hypervariable mitochondrial control region

The goitered gazelle, Gazella subgutturosa, is a medium-sized ungulate inhabiting arid and semi-arid regions in the Middle East and central Asia. The intraspecific classification of the species remains unclear. We analysed the genetic diversity in mitochondrial DNA control region (CR) sequences (976 bp) from 104 wild samples from the Xinjiang Uyghur Autonomous Region (XUAR) in north-west China, and reconstructed phylogeny with additional sequences from across the species’ range. We detected 58 haplotypes in XUAR populations, all but three of which were specific to single sampling sites. The phylogenetic analysis displayed two obvious clades of mtDNA haplotypes and the other haplotypes differed from the two clades. A median-joining network showed three groups of haplotypes were to a high extent concordant with the phylogenetic tree. The haplotype clustering was consistent with their geographic distribution. Nei’s net sequence divergences amongst the three groups ranged from 0.010 to 0.018 and indicated three subspecies, two of which inhabit XUAR. We detected strong differentiation between northern (NX) and southern (SX) XUAR populations overall (FST = 0.4448, P < 0.001), but the Mantel test showed no correlation between the genetic distance and geographic distance. Our results indicate that the NX and SX populations represent different subspecies that might be managed separately.

Population structure of North Atlantic and North Pacific sei whales (Balaenoptera borealis) inferred from mitochondrial control region DNA sequences and microsatellite genotypes

Currently, three stocks of sei whales (Balaenoptera borealis) are defined in the North Atlantic; the Nova Scotian, Iceland-Denmark Strait and Eastern North Atlantic stocks, which are mainly based upon historical catch and sighting data. We analyzed mitochondrial control region DNA (mtDNA) sequences and genotypes from 7 to 11 microsatellite loci in 87 samples from three sites in the North Atlantic; Iceland, the Gulf of Maine and the Azores, and compared against the North Pacific using 489 previously published samples. No statistically significant deviations from homogeneity were detected among the North Atlantic samples at mtDNA or microsatellite loci. The genealogy estimated from the mtDNA sequences revealed a clear division of the haplotypes into a North Atlantic and a North Pacific clade, with the exception of one haplotype detected in a single sample from the Azores, which was included in the North Pacific clade. Significant genetic divergence between the North Atlantic and North Pacific Oceans was detected (mtDNA ΦST = 0.72, microsatellite Weir and Cockerham’s ϴ = 0.20; p < 0.001). The coalescent-based estimate of the population divergence time between the North Atlantic and North Pacific populations from the sequence variation among the mtDNA sequences was at 163,000 years ago. However, the inference was limited by an absence of samples from the Southern Hemisphere and uncertainty regarding mutation rates and generation times. The estimates of inter-oceanic migration rates were low (Nm at 0.007 into the North Pacific and at 0.248 in the opposite direction). Although estimates of genetic divergence among the current North Atlantic stocks were low and consistent with the extensive range of movement observed in satellite tagged sei whales, the high uncertainty of the genetic divergence estimates precludes rejection of multiple stocks in the North Atlantic.

Ancient DNA analysis of Indigenous rockfish use on the Pacific Coast: Implications for marine conservation areas and fisheries management

Rockfish (Sebastes spp.) are a common marine fish in nearshore and continental shelf environments in the North Pacific Ocean. They are frequently identified in coastal archaeological sites in western North America; however, the morphological similarity of rockfish species limits conventional zooarchaeological identifications to the genus level. This study applies ancient DNA analysis to 96 archaeological rockfish specimens from four sites on separate islands in an archipelago on western Vancouver Island, British Columbia, Canada. Two of the archaeological sites are located within a marine protected area specifically designed to facilitate the recovery of inshore rockfish populations; two sites are located outside this boundary and remain subject to considerable fishing pressure. Using mitochondrial 16S and control region DNA sequences, we identify at least twelve different rockfish species utilized during the past 2,500 years. Identification of rockfish at closely spaced and contemporaneously occupied sites confirms that a variety of Sebastes species were consistently exploited at each site, with more exposed areas having a higher number of species present. Identification results indicate that four of the twelve species did not occur within the conservation area boundary and, instead, were found in sites where commercial and recreational fishing continues to be permitted. This study demonstrates that ancient DNA identifications of archaeological assemblages can complement and expand perspective on modern day fisheries conservation and management in this National Park Reserve and First Nations ancestral territory.

Redetection of human papillomavirus type 16 infections of the cervix in mid-adult life

PurposeTo assess whether HPV 16 originally detected in adolescent women can be redetected in adulthood. MethodsA convenience sample of 27 adult women with known HPV 16 detection during adolescence was assessed for HPV 16 redetection. A comparison of the long control region (LCR) DNA sequences was performed on some of the original and redetected HPV 16 isolates. ResultsMedian age at reenrollment was 27.5 years (interquartile range of 26.7–29.6). Reenrollment occurred six years on average after the original HPV 16 detection. Eleven of 27 women had HPV 16 redetected. Some of these HPV 16 infections had apparently cleared during adolescence. LCR sequencing was successful in paired isolates from 6 women; in 5 of 6 cases the redetected HPV 16 isolates were identical to those detected during adolescence, ConclusionsHPV 16 may be episodically detected in young women, even over long time periods. HPV 16 redetection with identical LCR sequences suggests low-level persistent infection rather than true clearance, although newly acquired infection with an identical HPV 16 isolate cannot be excluded. However, this study suggests that a new HPV 16-positive test in a clinical setting may not indicate a new infection.

Evidence of shallow mitochondrial divergence in the slender armorhead, Pentaceros wheeleri (Pisces, Pentacerotidae) from the Emperor Seamount Chain

Competitive overexploitation of the slender armorhead, Pentaceros wheeleri, a deep-sea fish inhabiting the Emperor Seamount Chain caused a serious population decline. Therefore, it is urgently necessary to clarify its genetic diversity and connectivity among populations of P. wheeleri for appropriate stock management. For this, we compared 677 base pairs (bp) of mitochondrial (mt) DNA control region (CR) sequences of 80 individuals from three seamounts (the Milwaukee, Kinmei, and Koko Seamounts) in the southern part of the Emperor Seamount Chain. Contrary to our expectation, the three seamount populations showed high genetic diversity, not yet reflecting effects from the recent population decline or due to mixed two clades. Analysis of molecular variance indicated no significant genetic differentiation between seamount populations, however, the neighbour-joining tree and minimum spanning network showed significant separation into two clades (K2P distance= 1.2–3.2%, ϕst = 0.5739, p < .05) regardless of seamount. The divergence time between the two clades was estimated to be 0.3–0.8 Mya, during the period of Pleistocene glacial cycles, suggesting that associated environmental changes and the unique life history traits of Pentaceros spp. might have resulted in the initiation of divergence between these clades.

&lt;b&gt;Dna barcoding, population genetics, and phylogenetics of the illegally hunted Philippine Duck &lt;I&gt;Anas luzonica&lt;/I&gt; (Aves: Anseriformes: Anatidae)&lt;/b&gt;

DNA barcoding is extensively used as a species identification and delineation tool. The aim of this study was to generate a barcode profile for mitochondrial cytochrome c oxidase subunit 1 (COI) in the Philippine Duck Anas luzonica, a dabbling duck species endemic to the Philippines that is classified as ‘Vulnerable’ by the International Union for Conservation of Nature (BirdLife International 2016). COI barcodes were successfully obtained using muscle tissue samples from 46 A. luzonica individuals confiscated from illegal hunters in Pantabangan, Nueva Ecija. Analysis of TrN+Γ+I distances among the Anas luzonica COI sequences and those of 25 other Anas species revealed that COI barcodes cannot generally delineate hybridizing species. While Anas luzonica was differentiated from other species it is known to hybridize with and formed a monophyletic group in the neighbor-joining tree generated, sampling from areas of sympatry is needed since individuals were obtained from only one sampling site. The population structure of the Anas luzonica population was also examined using mitochondrial DNA control region and COI sequences. The population had high haplotype diversity and low nucleotide diversity, an indication that a bottleneck event had occurred, which is likely due to extreme hunting pressures and habitat destruction. The population under study exhibited high genetic diversity. Given that the samples for this study came from a single locality, sampling from other localities is required to determine whether other populations are facing the risk of reduced fitness (inbreeding depression).

GENEBANK ANALYSIS: SINGLE NUCLEOTIDE POLYMORPHISMS OF ANIMALS MITOCHONDRIAL GENOME UKRAINIAN GRAY AND UKRAINIAN WHITEHEAD CATTLE BREEDS

Examination of variation in mitochondrial DNA (mtDNA) control region sequences has been pivotal in the elucidation of bovine phylogeography. Initial studies have demonstrated a deep bifurcation in bovine mtDNA phylogeny, which indicates a predomestic divergence between the two major taxa of cattle, humped zebu (Bos indicus) and humpless taurine (Bos taurus). Subsequent genetic investigations have yielded further inference regarding origins within the B. taurus lineage. B. taurus mtDNA sequences fall into one of five ancestral star-like haplotypic clusters, which are geographically distributed. Just one of these clusters, T3, predominates in Western Europe. Symmetrically, diversity within Africa is composed almost exclusively of members of a separate haplotypic cluster, T1, which is rarely detected elsewhere. The almost mutually exclusive geographic distribution of these two haplotypic clusters allows geographical exceptions to be securely identified as secondary introductions. We investigated a comparative analysis of mitochondrial genome sequences for different breeds of cattle (Bos taurus, Bos indicus) with global genetic bank. Mitochondrial DNA sequences from bovine animals (Bos taurus) breeds Ukrainian Whitehead and Ukrainian Gray freely available on the global genetic bank (http://www.ncbi.nlm.nih.gov/Genebank/). Local alignment of sequences for mitochondrial genome of different cattle breeds was performed using the program MEGA 4.0. For the detection of nucleotide replacements used mitochondrial DNA sequence of Bos taurus Hereford breed (Anderson S. at al., 1982) as a reference (accession number V00645). Here we report the analysis results of testing for 9 genotypes Ukrainian Gray mitochondrial DNA sequences showed that one animal (GQ129208) has haplotype Bos indicus, other belongs to haplogroup T1 with European origin mtDNA. Analysis of single nucleotide replacement in one of the hypervariable regions mtDNA (position number 16019-16339) shows, that among 10 submitted genotypes of Ukrainian Whitehead the 3 of them (FJ014303, FJ014298, FJ014294) relating to T1a mtDNA haplogroup of African origin, which characterized by replacement of T to C at position 16255. Also have been two animals (FJ014301, FJ014295) with single nucleotide replacements with relatives to Bos indicus mtDNA haplogroup. We performed alignment with reference sequences (Bos_taurus_v00654.1) and comparative nucleotide sequences analysis of another hypervariable D-loop (position number 1-240) mtDNA with 5 Ukrainian Whitehead genotypes and 5 Ukrainian Gray genotypes represented in genetics bank. Among the Ukrainian Whitehead genotypes (FJ014298, FJ014297, FJ014296, FJ014295, FJ014294) all were polymorphic that characterizes large differentiation these animals for maternal and describe deep heterogeneous parent population of studied group. We determined one animal with genotype FJ014295 was significantly different by the number of segregation sites. The analyzed sequences (FJ014290, FJ014289, FJ014288, FJ014287, FJ014286) of 5 Ukrainian Gray genotypes showed no polymorphism in hypervariable D-loop (position number 1-240) mtDNA. The mtDNA analysis of different species of animals allowed to distribute their mtDNA belonging to European, African and Asian haplogroups. The technique, which allows to differentiate the animals represented by their belonging to the respective haplogroups. The process that gave rise to different genotypes in one lineage is clearly of fundamental importance in understanding intraspecific mitochondrial polymorphism and evolution in mammals. Сomprehensive study genetic material provide more opportunities to optimize costs in-situ conservation of different cattle breeds, to optimize methods and techniques which used in ex-situ conservation programmes of National gene bank of animal genetic resources.

Yangtze River, an insignificant genetic boundary in tufted deer (Elaphodus cephalophus): the evidence from a first population genetics study.

Great rivers were generally looked at as the geographical barrier to gene flow for many taxonomic groups. The Yangtze River is the third largest river in the world, and flows across South China and into the East China Sea. Up until now, few studies have been carried out to evaluate its effect as a geographical barrier. In this study, we attempted to determine the barrier effect of the Yangtze River on the tufted deer (Elaphodus cephalophus) using the molecular ecology approach. Using mitochondrial DNA control region (CR) sequences and 13 nuclear microsatellite loci, we explored the genetic structure and gene flow in two adjacent tufted deer populations (Dabashan and Wulingshan populations), which are separated by the Yangtze River. Results indicated that there are high genetic diversity levels in the two populations, but no distinguishable haplotype group or potential genetic cluster was detected which corresponded to specific geographical population. At the same time, high gene flow was observed between Wulingshan and Dabashan populations. The tufted deer populations experienced population decrease from 0.3 to 0.09 Ma BP, then followed by a distinct population increase. A strong signal of recent population decline (T = 4,396 years) was detected in the Wulingshan population by a Markov-Switching Vector Autoregressions(MSVAR) process population demography analysis. The results indicated that the Yangtze River may not act as an effective barrier to gene flow in the tufted deer. Finally, we surmised that the population demography of the tufted deer was likely affected by Pleistocene climate fluctuations and ancient human activities.

Genetic connectivity across marginal habitats: the elephants of the Namib Desert.

Locally isolated populations in marginal habitats may be genetically distinctive and of heightened conservation concern. Elephants inhabiting the Namib Desert have been reported to show distinctive behavioral and phenotypic adaptations in that severely arid environment. The genetic distinctiveness of Namibian desert elephants relative to other African savanna elephant (Loxodonta africana) populations has not been established. To investigate the genetic structure of elephants in Namibia, we determined the mitochondrial (mt) DNA control region sequences and genotyped 17 microsatellite loci in desert elephants (n = 8) from the Hoanib River catchment and the Hoarusib River catchment. We compared these to the genotypes of elephants (n = 77) from other localities in Namibia. The mtDNA haplotype sequences and frequencies among desert elephants were similar to those of elephants in Etosha National Park, the Huab River catchment, the Ugab River catchment, and central Kunene, although the geographically distant Caprivi Strip had different mtDNA haplotypes. Likewise, analysis of the microsatellite genotypes of desert‐dwelling elephants revealed that they were not genetically distinctive from Etosha elephants, and there was no evidence for isolation by distance across the Etosha region. These results, and a review of the historical record, suggest that a high learning capacity and long‐distance migrations allowed Namibian elephants to regularly shift their ranges to survive in the face of high variability in climate and in hunting pressure.

Population genetic structure and historical dispersal patterns in the subterranean rodent Ctenomys “chasiquensis” from the southeastern Pampas region, Argentina

Gene flow plays an essential role in the evolutionary history of the organisms and helps to identify those historical landscape features that most likely had affected the dispersal patterns. In this work, we assess, using mitochondrial control region DNA sequences, the historical migration patterns and population structure in Ctenomys “chasiquensis”, a highly, vulnerable and endemic subterranean rodent distributed in a very small area from the central part of Argentina. We used Bayesian and maximum likelihood approaches to evaluate the effects of historical gene flow among populations. Moreover, we used Bayesian skyline plots, tests of neutrality and mismatch distributions to assess the potential changes in population size through time. Our analyses show that populations of C. “chasiquensis” are moderate structured at regional level and this population pattern is probably the result of an asymmetric historical gene flow essentially from the South-West to the North-West, further of a recent demographic population expansion in the North-West, in conjunction with an important degree of isolation in some populations over its eastern geographical range. Evidently, historical gene flow seems to have been more frequently on the West. Finally, a close relationship appears to exist between the major climatic episodes occurred during the Late Quaternary in the central region of Argentina and the main historical demographic changes inferred for C. “chasiquensis”. The current distribution of C. “chasiquensis” appear to be a relicts of a more extended historical distribution in the Argentinean Pampas in the Late Pleistocene, with a perceptible population decline at the beginning of the Holocene. In this context, Bayesian demographic inferences showed a small but constant increment of population expansion of this species from approximately 90,000 to 11,000 years BP, after which a period of decrease in population size (that started in the early Holocene and continues nowadays) was observed.

Identification of skipjack tuna juveniles based on DNA control region sequences and potential spawning area around reunion island

In this study, we confirmed that DNA control region can be used to identify potential spawning area from pelagic juveniles species. We used the mitochondrial DNA control region to identify tuna juveniles predated by common dolphinfish and sampled in surface waters around Reunion Island. These were skipjack juveniles at an early stage (small length and young age). The biological results confirmed the species identification based on DNA analysis. Catch data by longline reveal a higher number of skipjack from October to December around Reunion Island corresponding to the period of our skipjack juvenile sampling.

Genetic structure, population demography and seasonal occurrence of blacktip shark Carcharhinus limbatus in Bimini, the Bahamas.

A longline survey was conducted from 2004 to 2014 to investigate the demographic population structure and seasonal abundance of the blacktip shark Carcharhinus limbatus in the Bimini Islands, the Bahamas. All individuals sampled (n = 242) were sub-adult or adults [70·1-145·1 cm pre-caudal length (LPC) range] with no neonates or YOY recorded in Bimini. Carcharhinus limbatus abundance peaked in September, coincident with the largest ratio of female to male sharks and a peak in fresh mating wounds on females. Mitochondrial control region (mtCR) DNA sequences were obtained from C. limbatus at Bimini to test whether Bimini C. limbatus are most closely related to geographically proximate populations sampled on the south-eastern coast of the U.S.A., the closest known nursery areas for this species. Nine mtCR haplotypes were observed in 32 individuals sampled at Bimini [haplotype diversity (h) = 0·821, nucleotide diversity (π) = 0·0015]. Four haplotypes observed from Bimini matched those previously found in the northern Yucatan (Mexico)-Belize and two matched a haplotype previously found in the U.S.A. Four haplotypes were novel but were closely related to the northern Yucatan-Belizean haplotypes. Pair-wise ΦST analysis showed that Bimini was significantly differentiated from all of the populations previously sampled (U.S.A. Atlantic, U.S.A. Gulf of Mexico, northern Yucatan, Belize and Brazil). This indicates that C. limbatus sampled from Bimini are unlikely from the described, proximate U.S.A. nurseries.

Comparison of Patterns of Genetic Variation and Demographic History in the Greater Sage-Grouse (Centrocercus urophasianus): Relevance for Conservation

The greater sage-grouse (Centrocercus urophasianus) was once widespread in western North America but its range has contracted by an uncertain degree owing to anthropogenic and natural causes. Concern over population declines has led to its proposed listing as threatened under the U.S. Endangered Species Act. Detailed genetic and demographic analyses of this species throughout its range are available but heretofore have not been compared. Reduced genetic variability is often taken as a proxy for declining populations, but rarely are there quantitative population estimates with which to compare. I compared published mitochondrial DNA (mtDNA) control region sequences, microsatellite allele frequencies at seven loci, and estimates of numbers of males per lek, number of active leks, percent decline in the best population models, and the probability (P) of Ne &lt; 50 in 30 years and P(Ne &lt; 500) in 100 years, at two spatial scales, 45 local population samples and 16 larger aggregates of samples. When excluding the populations from the Columbia Basin, which show little genetic diversity and are statistical outliers, there were no consistent relationships between estimates of genetic variation and demographic trends across the remainder of the range at either spatial scale. A measure of inbreeding derived from microsatellite data was also not related to population trends. Thus, despite habitat reduction and range fragmentation, the greater sage-grouse does not exhibit expected genetic signatures of declining populations. Possibly, the mtDNA and microsatellite data are insufficiently sensitive to detect population declines that have occurred over the span of a half century. Alternatively, only when populations are reduced to the levels seen in the Columbia Basin will genetic effects be seen, suggesting that the bulk of the range of the greater sage-grouse is not currently in genetic peril.