|Genetic diversity of island populations of the common shrew Sorex araneus|
White Th.A., Searle J.B.
Populations of many species are currently being fragmented and reduced by human interactions. These processes will tend to reduce genetic diversity within populations due to genetic drift, inbreeding and reduced migration. Conservation biologists need to know the effect of population size on genetic diversity as this is likely to influence a population’s ability to persist. Island populations represent an ideal natural experiment with which to study this problem. In a study of common shrews (Sorex araneus) on offshore Scottish islands, 147 individuals from 6 islands of different sizes and 2 mainland sites were trapped and genotyped at 10 microsatellite loci. Pairwise FST values (between 0.06 and 0.56) showed that all the island populations were significantly genetically divergent from one another. All island populations exhibited lower allelic diversity and heterozygosity than the mainland populations, and these measures of genetic diversity were positively correlated with log island size.
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