SC/59/BRG32 1 A Note on Interannual Variation of Fis for

• Main Author: Bowhead Whales
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Chukchi
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.585.2293; http://www.iwcoffice.co.uk/_documents/sci_com/SC59docs/SC-59-BRG32.pdf

Jorde and Schweder (2007) present a boxplot of locus-specific estimates of Fis for a sample of Bering-Chukchi-Beaufort Seas (BCB) bowhead whales split by sample year, for 206 whales and 33 microsatellite loci. In their figure, the 8 samples from 1992 exhibit Fis estimates that vary more widely and average higher than do samples from other years (Jorde and Schweder, 2007, Figure 1). They cite this result as evidence that BCB bowhead samples are “not representing a single biological population.” There are other more likely explanations. I re-analyzed thebowhead data to investigate the finding of Jorde and Schweder. The data I used comprised microsatellite scores for 213 whales caught at Barrow, for 33 loci. These are the same loci and nearly the same whales used by Jorde and Schweder. Indeed, using my data I can replicate their boxplot; see Figure 1. There are several aspects of the 1992 samples that are special. First, 1992 is among the years for which the fewest samples (8) are available, so 1992 estimates of allele frequencies and Fis are highly variable compared to other years. Second, three 1992 individuals (92B3, 92B5, and 92B6) have unusual homozygosity