Retroposition is a widespread phenomenon resulting in the generation of new genes that are initially related to a parent gene via very high coding sequence similarity. We examine the evolutionary fate of four retrogenes generated by such an event; mouse Inpp5f_v2, Mcts2, Nap1l5, and U2af1-rs1. These genes are all subject to the epigenetic phenomenon of parental imprinting. We first provide new data on the age of these retrogene insertions. Using codon-based models of sequence evolution, we show these retrogenes have diverse evolutionary trajectories, including divergence from the parent coding sequence under positive selection pressure, purifying selection pressure maintaining parent-retrogene similarity, and neutral evolution. Examination of the expression pattern of retrogenes shows an atypical, broad pattern across multiple tissues. Protein 3D structure modeling reveals that a positively selected residue in U2af1-rs1, not shared by its parent, may influence protein conformation. Our case-by-case analysis of the evolution of four imprinted retrogenes reveals that this interesting class of imprinted genes, while similar in regulation and sequence characteristics, follow very varied evolutionary paths.
http://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2010.01213.x/abstract
Complete reference:
McCole RB, Loughran NB, Chahal M, Fernandes LP, Roberts RG, Fraternali F, O’Connell MJ, Oakey RJ (2011) A Case-by-case evolutionary analysis of four Imprinted retrogenes. DOI: 10.1111/j.1558-5646.2010.01213.x Evolution. pdf .
