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Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

Journal of Heredity

By:
, , , , and
DOI: 10.1093/jhered/esp061

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Abstract

Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother-offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother-offspring pairs and identified 10 additional mother-cub pairs and 48 father-offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (rxy) of approximately zero, parent-offspring and siblings had rxy of approximately 0.5, and 5.2% of the samples had rxy values within the range expected for parent-offspring. Effective population size (Ne = 277) and the ratio of Ne to total population size (Ne/N = 0.182) were estimated from the numbers of reproducing males and females. Ne estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and Ne in a polar bear population. ?? The American Genetic Association. 2009. All rights reserved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
Series title:
Journal of Heredity
DOI:
10.1093/jhered/esp061
Volume
100
Issue:
6
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Heredity
First page:
681
Last page:
690
Number of Pages:
10