Genomic sex identification of ancient pinnipeds using the dog genome

Determining the proportion of males and females in zooarchaeological assemblages can be used to reconstruct diversity severity past anthropogenic impacts on animal populations, also provide valuable biological insights into life-histories, behaviour demography, including effects environmental change. However, such inferences have often not been possible due fragmented nature record a lack clear diagnostic skeletal markers. In this study, we test whether dog (Canis lupus familiaris) nuclear genome is suitable for genetic sex identification pinnipeds. We initially tested 72 contemporary ringed seal (Pusa hispida) genomes with known sex, using X chromosome DNA reads 1 (i.e. chrX/chr1-ratio) distinguish from females. This method was found highly reliable, ratios clustering two clearly distinguishable groups, allowing 69 individuals correctly identified according sex. Secondly, determine lower limit required method, subset data randomly down-sampled. threshold as few 5000 mapped sequence reliable identification. Finally, applying standard, successfully carried out broad set ancient pinniped samples, walruses (Odobenus rosmarus), grey seals (Halichoerus grypus) harp (Pagophilus groenlandicus). All three species showed distinct male female chrX/chr1 ratio providing 42–98% depending sample quality. The approach described study should aid untangling putative human activities change populations pinnipeds other species.