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Joseph I Hoffman - One of the best experts on this subject based on the ideXlab platform.
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Morphological and genetic evidence for two evolutionarily significant units (ESUs) in the South American fur seal, Arctocephalus gazella
Conservation Genetics, 2008Co-Authors: Larissa Rosa Oliveira, Joseph I Hoffman, Erika Hingst-zaher, Patricia Majluf, Mônica M. C. Muelbert, João Stenghel Morgante, William AmosAbstract:The South American fur seal ( Arctocephalus australis ) is widely distributed, occurring along both the Atlantic and the Pacific coasts of South America. Previous work suggests there may be more than one subspecies, highlighting the need for further study. Here, we combine traditional and geometric morphometric analysis of skull shape and size with genetic data to compare two populations of South American fur seals, one from Uruguay and one from Peru. As a control group we used material from the closely related species Arctocephalus gazella . Both techniques of morphometric analysis reveal pronounced geographic variation in size and shape of the skull, with Peruvian specimens ( n = 102) being larger than Uruguayan skulls ( n = 133) and significant shape differences concentrated in the rostral region. Similarly, seven highly polymorphic microsatellite loci reveal highly significant differences in allele frequency. Moreover, Bayesian analysis implemented using the program structure reveals two separate clusters corresponding perfectly to the two populations, with an assignment test correctly placing over 98% of specimens in their population of origin. This degree of differentiation for both genetic and morphological traits suggests complete and possibly prolonged isolation to the extent that we believe these populations should be considered distinct evolutionarily significant units.
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Ten novel polymorphic dinucleotide microsatellite loci cloned from the Antarctic fur seal Arctocephalus gazella
Molecular Ecology Resources, 2008Co-Authors: Joseph I Hoffman, Kanchon K Dasmahapatra, Hazel J NicholsAbstract:Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.
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permanent genetic resources ten novel polymorphic dinucleotide microsatellite loci cloned from the antarctic fur seal Arctocephalus gazella
Molecular Ecology Resources, 2008Co-Authors: Joseph I Hoffman, Kanchon K Dasmahapatra, Hazel J NicholsAbstract:Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.
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ten novel dinucleotide microsatellite loci cloned from the galapagos sea lion zalophus californianus wollebaeki are polymorphic in other pinniped species
Molecular Ecology Notes, 2006Co-Authors: Joseph I Hoffman, Jochen B W WolfAbstract:We isolated and characterized 10 novel dinucleotide microsatellite loci from the Galapagos sea lion (Zalophus californianus wollebaeki) and tested their amplification utility in four further otariid species (Zalophus californianus californianus, Arctocephalus gazella, Arctocephalus australis and Eumetopias jubatus) and three phocid species (Hydrurga leptonyx, Halichoerus grypus and Phoca vitulina). All of the loci amplified polymorphic polymerase chain reaction (PCR) products in at least three species other than the Galapagos sea lion. These markers will be useful for studies of pinniped mating systems, genetic structure and genetic diversity.
Hazel J Nichols - One of the best experts on this subject based on the ideXlab platform.
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permanent genetic resources ten novel polymorphic dinucleotide microsatellite loci cloned from the antarctic fur seal Arctocephalus gazella
Molecular Ecology Resources, 2008Co-Authors: Joseph I Hoffman, Kanchon K Dasmahapatra, Hazel J NicholsAbstract:Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.
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Ten novel polymorphic dinucleotide microsatellite loci cloned from the Antarctic fur seal Arctocephalus gazella
Molecular Ecology Resources, 2008Co-Authors: Joseph I Hoffman, Kanchon K Dasmahapatra, Hazel J NicholsAbstract:Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.
Kanchon K Dasmahapatra - One of the best experts on this subject based on the ideXlab platform.
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permanent genetic resources ten novel polymorphic dinucleotide microsatellite loci cloned from the antarctic fur seal Arctocephalus gazella
Molecular Ecology Resources, 2008Co-Authors: Joseph I Hoffman, Kanchon K Dasmahapatra, Hazel J NicholsAbstract:Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.
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Ten novel polymorphic dinucleotide microsatellite loci cloned from the Antarctic fur seal Arctocephalus gazella
Molecular Ecology Resources, 2008Co-Authors: Joseph I Hoffman, Kanchon K Dasmahapatra, Hazel J NicholsAbstract:Ten new dinucleotide microsatellite loci were isolated from the Antarctic fur seal Arctocephalus gazella. These markers should prove useful for studying the reproductive ecology of Antarctic fur seals and other related pinniped species.
Jochen B W Wolf - One of the best experts on this subject based on the ideXlab platform.
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ten novel dinucleotide microsatellite loci cloned from the galapagos sea lion zalophus californianus wollebaeki are polymorphic in other pinniped species
Molecular Ecology Notes, 2006Co-Authors: Joseph I Hoffman, Jochen B W WolfAbstract:We isolated and characterized 10 novel dinucleotide microsatellite loci from the Galapagos sea lion (Zalophus californianus wollebaeki) and tested their amplification utility in four further otariid species (Zalophus californianus californianus, Arctocephalus gazella, Arctocephalus australis and Eumetopias jubatus) and three phocid species (Hydrurga leptonyx, Halichoerus grypus and Phoca vitulina). All of the loci amplified polymorphic polymerase chain reaction (PCR) products in at least three species other than the Galapagos sea lion. These markers will be useful for studies of pinniped mating systems, genetic structure and genetic diversity.
Paul Sunnucks - One of the best experts on this subject based on the ideXlab platform.
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menage a trois on macquarie island hybridization among three species of fur seal Arctocephalus spp following historical population extinction
Molecular Ecology, 2006Co-Authors: Melanie L Lancaster, Simon D Goldsworthy, Neil J Gemmell, Sandra Ms Negro, Paul SunnucksAbstract:Human-induced changes to natural systems can cause major disturbances to fundamental ecological and population processes and result in local extinctions and secondary contacts between formerly isolated species. Extensive fur seal harvesting during the nineteenth century on Macquarie Island (subantarctic) resulted in extinction of the original population. Recolonization by three species has been slow and complex, characterized by the establishment of breeding groups of Antarctic and subantarctic fur seals (Arctocephalus gazella and Arctocephalus tropicalis) and presumed nonbreeding (itinerant) male New Zealand fur seals (Arctocephalus forsteri). One thousand and seven pups from eight annual cohorts (1992-2003) were analysed using mitochondrial control region data (RFLP) and 10 microsatellite loci to estimate species composition and hybridization. Antarctic fur seals predominated, but hybridization occurred between all three species (17-30% of all pups). Involvement of New Zealand fur seals was unexpected as females are absent and males are not observed to hold territories during the breeding season. The proportion of hybrids in the population has fallen over time, apparently owing to substantial influxes of pure Antarctic and subantarctic individuals and non-random mating. Over 50% of New Zealand hybrids and 43% of Antarctic-subantarctic hybrids were not F(1), which indicates some degree of hybrid reproductive success, and this may be underestimated: simulations showed that hybrids become virtually undetectable by the third generation of backcrossing. While human impacts seem to have driven novel hybridization in this population, the present 'time slices' analysis suggests some biological resistance to complete homogenization.