Braasch, I., and Postlethwait, J.H. (2011) The teleost agouti-related protein 2 gene is an ohnolog gone missing from the tetrapod genome. Proceedings of the National Academy of Sciences of the United States of America. 108(13):E47-E48.
A central question in evolutionary genomics is how morphological differences between taxa arise from differences in gene repertoire.
Answers require rigorous orthology assignments. Recent work (1) illuminated the mechanism of background adaptation in teleost fishes by investigating the function of agouti-related protein 2 (agrp2), a gene so far found only in teleosts.