Meeting Abstract
Gamete-recognition proteins (GRG), expressed on the surface of gametes, mitigate the initiation of sperm hyperactivation, acrosome reaction, gamete binding and fusion. Few genetic changes in these proteins can lead to reproductive incompatibility. GRG are poorly described in mustelids and other mammals. This is in part due to duplication events, diversifying selection, loss of function, and convergence. Conservation breeding efforts of endangered species are encountering an increased number of fertilization problems linked to gamete health. For example, since the onset of the captive breeding program, the percentage of structurally-normal spermatozoa in the black-footed ferret has decreased from 50% to 20%, coincident with a decline in testes size. These features are indicative of inbreeding depression. To better understand fertilization in mustelids, we used whole genome data comparison to find and characterize genes linked to fertilization. In particular, we focused on finding orthologous GRG in mustelids and related taxa of the Carnivora. We characterized eight potential GRG and tested these for signatures of positive selection within a phylogenetic and machine learning framework using the software toolkit HyPhy. We identified regions of these genes under positive selection in mustelids, which have also been previously identified to be under selection in mice and humans. Our findings can help inform functional analyses to confirm the patterns of expression and function of these orthologous GRG in mustelids and other carnivores. Furthermore, these genes can be used in combination with additional fertilization genes to identify healthy gametes for ex situ and in situ population breeding efforts of endangered species.
