Research Document - 2002/092
Genetic relationships among Atlantic walrus (Odobenus rosmarus rosmarus) in the Foxe Basin and the Resolute Bay-Bathurst Island area
By de March, B.G.E., Maiers, L.D. and Stewart, R.E.A.
Abstract
Maternally inherited mitochondrial DNA (mtDNA) and alleles at 13 nuclear DNA microsatellite loci were analysed for walrus from the putative Foxe Basin stock (Hall Beach n=71, Igloolik n=75 and from the putative Baffin Bay stock (Grise Fiord n=5 and Resolute Bay/Bathurst Island n=18). The data were examined for genetic differences among the 4 groups and also for annual differences within the 4 groups. Results strongly supported the hypothesis that Foxe Basin walrus and Baffin Bay walrus were different stocks, but did not support the hypotheses of further stock division. Hall Beach and Igloolik walrus were not significantly differentiated from each other, nor were Grise Fiord and Resolute Bay/Bathurst Island walrus. A lower than expected degree of heterozygosity within individuals indicated that some walrus were inbred. This is believed to be due to the harem mating system of walrus. Nevertheless, there is still a high degree of genetic diversity in walrus. The probability of sampling pairs of individuals that have a parent-offspring-like genetic relationship is quite high, approximately 0.01 for microsatellites and 0.001 for microsatellites and haplotypes combined. Therefore, it is difficult to identify true parent-offspring pairs in a large population. The use of more genetic markers would make this type of identification more certain. The use of molecular genetics to study the mating systems and movements of walrus is discussed.
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