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Population structure as revealed by mtDNA and microsatellites in northern fur seals, Callorhinus ursinus, throughout their range.

Dickerson BR, Ream RR, Vignieri SN, Bentzen P - PLoS ONE (2010)

Bottom Line: Using microsatellite and mitochondrial loci, we examined population structure in NFS throughout their range.We found only weak population genetic structure among breeding islands including significant F(ST) and Phi(ST) values between eastern and western Pacific islands.We conclude that insufficient time since rapid population expansion events (both post glacial and following the cessation of intense harvest pressure) mixed with low levels of contemporary migration have resulted in an absence of genetic structure across the entire northern fur seal range.

View Article: PubMed Central - PubMed

Affiliation: National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, Seattle, Washington, United States of America. Bobette.Dickerson@noaa.gov

ABSTRACT

Background: The northern fur seal (Callorhinus ursinus; NFS) is a widely distributed pinniped that has been shown to exhibit a high degree of philopatry to islands, breeding areas on an island, and even to specific segments of breeding areas. This level of philopatry could conceivably lead to highly genetically divergent populations. However, northern fur seals have the potential for dispersal across large distances and have experienced repeated rapid population expansions following glacial retreat and the more recent cessation of intensive harvest pressure.

Methodology/principal findings: Using microsatellite and mitochondrial loci, we examined population structure in NFS throughout their range. We found only weak population genetic structure among breeding islands including significant F(ST) and Phi(ST) values between eastern and western Pacific islands.

Conclusions: We conclude that insufficient time since rapid population expansion events (both post glacial and following the cessation of intense harvest pressure) mixed with low levels of contemporary migration have resulted in an absence of genetic structure across the entire northern fur seal range.

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Related in: MedlinePlus

The observed pairwise mismatch distribution of mtDNA in northern fur seals as compared to the expected distribution based upon a model of sudden population expansion.
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pone-0010671-g006: The observed pairwise mismatch distribution of mtDNA in northern fur seals as compared to the expected distribution based upon a model of sudden population expansion.

Mentions: Evidence for past population expansion was strong. The unimodality of the nucleotide frequency mismatch distribution was almost identical to a model of sudden expansion. These results suggest that northern fur seals have undergone a rapid expansion event in recent evolutionary history and that the signature of this event is still evident in their genetic composition (Figure 6). The results of the skyline analysis further support this conclusion showing a rapid increase in population size starting ∼11000 ybp, followed by a more recent decrease in population numbers starting ∼2000 ybp (Figure 7).


Population structure as revealed by mtDNA and microsatellites in northern fur seals, Callorhinus ursinus, throughout their range.

Dickerson BR, Ream RR, Vignieri SN, Bentzen P - PLoS ONE (2010)

The observed pairwise mismatch distribution of mtDNA in northern fur seals as compared to the expected distribution based upon a model of sudden population expansion.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2871788&req=5

pone-0010671-g006: The observed pairwise mismatch distribution of mtDNA in northern fur seals as compared to the expected distribution based upon a model of sudden population expansion.
Mentions: Evidence for past population expansion was strong. The unimodality of the nucleotide frequency mismatch distribution was almost identical to a model of sudden expansion. These results suggest that northern fur seals have undergone a rapid expansion event in recent evolutionary history and that the signature of this event is still evident in their genetic composition (Figure 6). The results of the skyline analysis further support this conclusion showing a rapid increase in population size starting ∼11000 ybp, followed by a more recent decrease in population numbers starting ∼2000 ybp (Figure 7).

Bottom Line: Using microsatellite and mitochondrial loci, we examined population structure in NFS throughout their range.We found only weak population genetic structure among breeding islands including significant F(ST) and Phi(ST) values between eastern and western Pacific islands.We conclude that insufficient time since rapid population expansion events (both post glacial and following the cessation of intense harvest pressure) mixed with low levels of contemporary migration have resulted in an absence of genetic structure across the entire northern fur seal range.

View Article: PubMed Central - PubMed

Affiliation: National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, Seattle, Washington, United States of America. Bobette.Dickerson@noaa.gov

ABSTRACT

Background: The northern fur seal (Callorhinus ursinus; NFS) is a widely distributed pinniped that has been shown to exhibit a high degree of philopatry to islands, breeding areas on an island, and even to specific segments of breeding areas. This level of philopatry could conceivably lead to highly genetically divergent populations. However, northern fur seals have the potential for dispersal across large distances and have experienced repeated rapid population expansions following glacial retreat and the more recent cessation of intensive harvest pressure.

Methodology/principal findings: Using microsatellite and mitochondrial loci, we examined population structure in NFS throughout their range. We found only weak population genetic structure among breeding islands including significant F(ST) and Phi(ST) values between eastern and western Pacific islands.

Conclusions: We conclude that insufficient time since rapid population expansion events (both post glacial and following the cessation of intense harvest pressure) mixed with low levels of contemporary migration have resulted in an absence of genetic structure across the entire northern fur seal range.

Show MeSH
Related in: MedlinePlus