Authors: Gabriel Hammond, Rebecca Seegraber, Tim Webster
Mentors: Tim Webster
Insitution: University of Utah
Bornean and Sumatran orangutans demonstrate pronounced differences in their social behavior. All orangutans are more solitary than other apes and monkeys, but Bornean orangutans are even less social than their Sumatran counterparts. This contrast is generally attributed to differences in forest productivity between the two islands, as feeding competition is a major cost to social behavior. Variation in sociality between the two species directly impacts male reproductive skew, or the extent to which males can monopolize reproductive success. Sex-biased demographic phenomena such as male reproductive skew can be reconstructed across a lineage’s history by comparing genetic variation across different regions of the genome. Autosomes and the X chromosome are inherited in different proportions, in a population with an equal sex ratio, four autosome copies will be passed down for every three X chromosomes. Deviations in genetic diversity from this expected ratio can be indications of sex biased demographic events. This project is leveraging differential inheritance of chromosomes to explore the role of orangutan socioecology in shaping male reproductive strategies through genomic analysis of reproductive skew across Bornean and Sumatran orangutans.