1Department of Anthropology, Pennsylvania State University, 2Center for Conservation and Research, Omaha’s Henry Doorly Zoo and Aquarium, 3Center for Comparative Genomics and Bioinformatics, Pennsylvania State University, 4Department of Anthropology, University of Calgary
Thursday All day, Clinch Concourse
Aye-ayes are highly specialized extractive foragers, with the largest species distribution of any lemur. Across this distribution, they inhabit divergent forest types – from humid primary forests to relatively dry and deciduous forests. Such extensive habitat variation raises the possibility of population-specific ecological adaptation that may have left genomic signatures of selection. To detect such signatures, we collected whole genome sequence data from 12 wild aye-ayes from three geographically distinct areas in Madagascar (East, West and North regions). We estimated population differentiation for each detected SNP using the FST statistic. Extreme FST values in gene coding regions may reflect a history of region-specific positive selection, because the frequencies of adaptive alleles may have been subject to rapid increase. Indeed, we observed a relative excess of high FST nonsynonymous (amino acid changing) SNPs in the East population compared to the North and West populations. The genes containing high FST nonsynonymous SNPs include CLGN (FST = 0.82), which is necessary for the production of fertile sperm, and two genes involved in eye development, ADAM9 (FST = 0.82) and HMCN1 (FST = 0.67). ADAM9 mutations are associated with human cone-rod dystrophy, and knockout mice exhibit reduced photoreceptor responsiveness. HMCN1 is expressed in retinal cells and mutations in this gene have been associated with macular degeneration. Though additional study is needed, these results may be interesting with respect to the aye-aye’s nocturnal activity pattern and potentially strong selective pressures associated with low-light foraging.