Insight into Evolution of Gene Regulation Networks from the Opossum Genome

Abstract

The Brazilian short-tailed grey opossum Monodelphis domestica was the first marsupial genome to be sequenced. The high quality draft genome sequence has provided significant new understanding of mammal genome evolution, suggesting that innovation in protein coding genes occurs primarily by diversification of existing gene families and that truly novel protein coding genes are rare. The opossum genome also highlights the magnitude of the role transposable elements have had in shaping gene regulatory networks, including X chromosome inactivation. The rate of innovation of new conserved non-coding elements is 20 fold higher than for protein coding genes, and a substantial portion of the novel eutherian specific conserved non-coding elements can be attributed to arising from transposable elements. Combined with insights into the role of recombination on genome composition and structure, the opossum genome has provided unique insight into the forces that shaped the genomes of all mammals.