Horse Y chromosome assembly displays unique evolutionary features and putative stallion fertility genes
Dynamic evolutionary processes and complex structure make the Y chromosome among the most diverse and least understood regions in mammalian genomes. Here, we present an annotated assembly of the male specific region of the horse Y chromosome (eMSY), representing the first comprehensive Y assembly in odd-toed ungulates. The eMSY comprises single-copy, equine specific multi-copy, PAR transposed, and novel ampliconic sequence classes. The eMSY gene density approaches that of autosomes with the highest number of retained X–Y gametologs recorded in eutherians, in addition to novel Y-born and transposed genes. Horse, donkey and mule testis RNAseq reveals several candidate genes for stallion fertility. A novel testis-expressed XY ampliconic sequence class, ETSTY7, is shared with the parasite Parascaris genome, providing evidence for eukaryotic horizontal transfer and inter-chromosomal mobility. Our study highlights the dynamic nature of the Y and provides a reference sequence for improved understanding of equine male development and fertility.
Janečka, J., Davis, B., Ghosh, S., Paria, N., Das, P., Orlando, L., Schubert, M., Nielsen, M., Stout, T., Brashear, W., Li, G., Johnson, C., Metz, R., Zadjali, A., Love, C., Varner, D., Bellott, D., Murphy, W., Chowdhary, B., & Raudsepp, T. (2018). Horse Y chromosome assembly displays unique evolutionary features and putative stallion fertility genes. Nature Communications, 9 (1). https://doi.org/10.1038/s41467-018-05290-6