Ruminant Comparative Genomics as a Tool for Tracing the Formation and Evolution of the Production Traits

The unique adaptations, ecological importance, and economical significance have made ruminants a prime target for genome sequencing. In this study we focused on the analysis of chromosomal rearrangements that occurred in the ancestral ruminant genome ~60-35 Mya in order to shed light on the evolution of economically important organs. The genomes of artiodactyls, including eight ruminants, and eight outgroup species were compared. We detected evolutionary breakpoint regions (EBRs) in the ancestral artiodactyl genome and ruminant-specific EBRs. To investigate the potential adaptive value of ancestral EBRs, we studied genes and gene networks affected by genome rearrangements in artiodactyls. Ruminant EBRs are enriched for genes related to immunological function, e.g., they reorganize the MHC Class II cluster, which is involved in adaptive immunity and also reorganize the IgA pathway, involved in the rumen’s ability to maintain a wide range of symbiotic bacteria.