摘要:

AbstractWe investigate the utility of hypervariable microsatellite loci to measure genetic variability remaining in the northern hairy‐nosed wombat, one of Australia's rarest mammals. This species suffered a dramatic range and population reduction over the past 120 years and now exists as a single colony of about 70 individuals at Epping Forest National Park, central Queensland. Because our preliminary research on mitochondrial DNA and multilocus DNA fingerprints did not reveal informative variation in this population, we chose to examine variation in microsatellite repeats, a class of loci known to be highly polymorphic in mammals. To assess the suitability of various wombat populations as a reference for comparisons of genetic variability and subdivision we further analysed mitochondrial DNA cytochromebsequence, using phylogenetic methods. Our results show that appreciable levels of variation still exist in the Epping Forest colony although it has only 41% of the heterozygosity shown in a population of a closely‐related species. From museum specimens collected in 1884, we also assessed microsatellite variation in an extinct population of the northern hairy‐nosed wombat, from Deniliquin, New South Wales, 2000 km to the south of the extant population. The apparent loss of variation in the Epping Forest colony is consistent with an extremely small effective population size throughout its 120‐year

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00068.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe Waldrapp ibis (Geronticus eretnita) is one of the most endangered birds in the wild. The only real hope for its survival seems to rest with captive propagation, which has fortunately proved straightforward. Preservation of genetic diversity for maintaining viable populations is a major goal in any species conservation programme. Therefore sensitive tools have to be developed for the detection and regular monitoring of population variability. Individual identity has to be verified and each individual's pedigree defined in order to enable effective selective breeding. In this study, extensive DNA fingerprinting technology was applied to a group of 39 captive Waldrapp ibises. Five minisatellite probes were used. Despite the fact that the colony was founded by only six birds and that some of the founders were apparently related, highly polymorphic banding patterns were obtained. The human‐ and pig‐derived probes MS1, MS31, pλg3 and pCMS12 each detected multiple distinct loci suitable for individual identification and resolution of parentage. Probe MS51 was locus‐specific and revealed six different alleles. In addition, MS31 and pλg3 co‐detected a band present in all females but none of the males and thus could be used for sex determination. For all but four individuals both parents could be identified unambiguously. The exceptions were offspring derived from a full sib mating in which DNA results allowed no distinction between the parents and the grandparents. Comparison of the parentage assigned by DNA analysis and by observation of breeding behaviour, respectively, showed agreement in all but five instances. Here, DNA data uncovered interchange of individuals in the stud book. Application of these minisatellite probes therefore offers an extremely sensitive means for individual identification and verification and completion of pedigre

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00069.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe world's most endangered canid is the Ethiopian wolfCanis simensis, which is found in six isolated areas of the Ethiopian highlands with a total population of no more than 500 individuals. Ethiopian wolf populations are declining due to habitat loss and extermination by humans. Moreover, in at least one population, Ethiopian wolves are sympatric with domestic dogs, which may hybridize with them, compete for food, and act as disease vectors. Using molecular techniques, we address four questions concerning Ethiopian wolves that have conservation implications. First, we determine the relationships of Ethiopian wolves to other wolf‐like canids by phylogenetic analysis of 2001 base pairs of mitochondrial DNA (mtDNA) sequence. Our results suggest that the Ethiopian wolf is a distinct species more closely related to gray wolves and coyotes than to any African canid. The mtDNA sequence similarity with gray wolves implies that the Ethiopian wolf may hybridize with domestic dogs, a recent derivative of the gray wolf. We examine this possibility through mtDNA restriction fragment analysis and analysis of nine microsatellite loci in populations of Ethiopian wolves. The results imply that hybridization has occurred between female Ethiopian wolves and male domestic dogs in one population. Finally, we assess levels of variability within and between two Ethiopian wolf populations. Although these closely situated populations are not differentiated, the level of variability in both is low, suggesting long‐term effective population sizes of less than a few hundred individuals. We recommend immediate captive breeding of Ethiopian wolves to protect their gene pool from dilution and further loss of genetic variabil

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00070.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe genetic structure of humpback whale populations and subpopulation divisions is described by restriction fragment length analysis of the mitochondrial (mt) DNA from samples of 230 whales collected by biopsy darting in 11 seasonal habitats representing six subpopulations, or ‘stocks’, world‐wide. The hierarchical structure of mtDNA haplotype diversity among population subdivisions is described using the analysis of molecular variance (AMOVA) procedure, the analysis of gene identity, and the genealogical relationship of haplotypes as constructed by parsimony analysis and distance clustering. These analyses revealed: (i) significant partitioning of world‐wide genetic variation among oceanic populations, among subpopulations or ‘stocks’ within oceanic populations and among seasonal habitats within stocks; (ii) fixed categorical segregation of haplotypes on the south‐eastern Alaska and central California feeding grounds of the North Pacific; (iii) support for the division of the North Pacific population into a central stock which feeds in Alaska and winters in Hawaii, and an eastern or ‘American’ stock which feeds along the coast of California and winters near Mexico; (iv) evidence of genetic heterogeneity within the Gulf of Maine feeding grounds and among the sampled feeding and breeding grounds of the western North Atlantic; and (v) support for the historical division between the Group IV (Western Australia) and Group V (eastern Australia, New Zealand and Tonga) stocks in the Southern Oceans. Overall, our results demonstrate a striking degree of genetic structure both within and between oceanic populations of humpback whales, despite the nearly unlimited migratory potential of this species. We suggest that the humpback whale is a suitable demographic and genetic model for the management of less tractable species of baleen whales and for the general study of gene flow among long‐lived, mobile vertebrates in t

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00071.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractSnakes are a particularly threatened vertebrate taxon, with distributions of many species and populations becoming increasingly fragmented. At present, little is known about the degree of genetic differentiation that exists between isolated populations even though such information may be critical to their survival and conservation. As an example of how recently developed RAPD genetic markers can be used in conservation genetics, we present preliminary results from a study which used these DNA‐based markers to assess population divergence in two threatened Canadian snakes, the black rat snake (Elaphe o. obsoleta) and the eastern massasauga rattlesnake (Sistrurus c. catenatus). We present information on the levels of variation and reliability of amplification for fragments generated from five primers. We then use a recently developed analytical technique to estimate levels of nucleotide diversity within populations and sequence divergence between populations. Our results show that intrapopulation levels of divergence as estimated by the methods of Clark&Lanigan (Molecular Biology and Evolution1993,10, 1096–1111) approximate those found for mtDNA in vertebrates and that diversity between snake populations is small and non‐significant when tested using randomization procedures. Thus, our study provides an example of how RAPDs can be applied to conservation genetic studies of vertebrates and suggest that the snake populations we examined have only recently become isolated and maybe considered genetically equivalent from a conservation perspective, although this conclusion needs to be confirmed with other DNA‐based

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00072.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis study uses isozyme electrophoresis to investigate the systematic status of two rare flightless chafer beetle species,Prodontria modestaandP. bicolorata, currently distinguished solely on the basis of colour. Seven polymorphic loci were analysed for the species in sympatry and allopatry. In sympatry, gene frequencies imply no genetic barrier between the two colour forms. Wright's hierarchical F‐statistics were calculated to determine how the genetic variation is partitioned across the geographic range of the two species. Strong geographic structuring occurs at the population level but there is little genetic differentiation attributable to species. Comparisons of morphological measurements are in support of the electrophoretic results. The systematic significance of the two distinct colour forms is thus questionable. Under the biological, recognition or phylogenetic species concepts, the genetic data suggest that there is only one species, polytypic for a colour pattern. Most of the genetic diversity of this group of beetles lies within and among populations, which differ quite markedly over their geographic range, rather than between the two named specie

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00073.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractGenetic heterogeneity is usually considered an important factor for the viability of a population, yet there are cases in which populations sustain themselves despite virtual homozygosity. A prior step to studying the effects of such low levels of genetic variability can be the analysis of its causes. We analysed a population of the highly social alpine marmot (Marmota marmota, Sciuridae) by multilocus DNA fingerprinting. The fingerprint patterns revealed a very low degree of polymorphism in our main study population. We show that this lack of hypervariability is caused by a low effective population size, rather than by an unusual low mutation rate of the fingerprint loci studied. However, the current number of breeding pairs was found to be about an order of magnitude larger than the one that would be expected to lead to such a low degree of heterozygosity. We conclude that there must have been bottlenecks in the history of the Berchtesgaden marmot population that have severely affected its genetic heterozygosity.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00074.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn the absence of pedigree information, the determination of genetic distinctness of populations can only be made by genetic methods. Using DNA fingerprinting on the North American captive herd of Speke's gazelleGazella spekei, we were able to address two hypotheses. First, two new individuals were found to have come from a genetically distinct population (P= 0.008, permutation test), and represent potential new founders to be added to the population. Secondly, genetic similarity was not significantly correlated with relatedness under extreme inbreeding and very close relationship (coefficient of relationship range 0.304‐0.717

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00075.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractWe describe a rapid and sensitive method for the detection of population‐specific genetic markers in mitochondrial DNA (mtDNA) and the use of such markers to analyse population structure of marine turtles. A series of oligonucleotide primers specific for the amplification of the mtDNA control region in Cheloniid turtles were designed from preliminary sequence data. Using two of these primers, a 384–385‐bp sequence was amplified from the 5′ portion of the mtDNA control region of 15 green turtlesChelonia mydasfrom 12 different Indo‐Pacific rookeries. Fourteen of the 15 individuals, including some with identical whole‐genome restriction fragment patterns, had sequences that differed by one or more base substitutions. Analysis of sequence variation among individuals identified a total of 41 nucleotide substitutions and a 1‐bp insertion/deletion. Comparison with evidence from whole‐genome restriction enzyme analysis of the same individuals indicated that this portion of the control region is evolving approximately eight times faster than the average rate and that the sequence analysis detected approximately one fifth of the total variation present in the genome. Restriction enzyme analysis of amplified products from an additional 256 individuals revealed significant geographic structuring in the distribution of mtDNA genotypes among five of the 10 rookeries surveyed extensively. Additional geographic structuring of genotypes was identified through denaturing gradient gel electrophoresis (DGGE) of amplified products. Only two of the 10 rookeries surveyed could not be differentiated, indicating that the Indo‐PacificC. mydasinclude a number of genetically differentiated populations, with minimal female‐mediated gene flow among them. Important applications for genetic markers in the conservation and management of marine turtles include the identification of appropriate demographic units for research and management (i.e. genetically discrete populations) and assessment of the composition of feeding and ha

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00076.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractRecent surveys suggest that the endangered St. Lawrence beluga (Delphinapterus leucas) population is not recovering significantly despite 20 years of protection. Dead individuals that have been autopsied show high levels of tumours and infections. This situation could be a result of pollution, loss of genetic variation, inbreeding depression or a combination of these factors. Analyses of DNA fingerprints from St. Lawrence belugas with three minisatellite probes (Jeffreys 33.6, 33.15 and M13) indicate a reduced level of genetic variation compared to Beaufort Sea animals. The average band‐sharing between individuals of the St. Lawrence beluga population for the three probes (0.534, 0.573 and 0.478, respectively) was significantly higher than that of the Beaufort Sea beluga population (0.343, 0.424, 0.314, respectively). Higher levels of mean allele frequency in the St. Lawrence belugas (0.33 vs. 0.21) suggest that this population is composed of individuals which are related. Inbreeding depression could therefore be a factor in the lack of recovery of the St. Lawrence beluga populatio

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1994.tb00077.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY