Evolution of hox complexes

Abstract

Recent years have seen a plethora of ideas and hypotheses, and lots of debate, about the origin and evolution of the Hox gene cluster. Here I will attempt to summarize these hypotheses, identify their strengths and weaknesses and highlight the types of new data that may lead to further resolution of the competing ideas. The major theme is that Hox genes originated very early in animal evolution and extensive independent duplications occurred in major lineages. Duplications however have not been the only route to change in the composition and structure of the Hox cluster, as extensive gene losses have occurred as well. Indeed it is gene loss that is one of the main obstacles in our understanding of the origin and evolution of Hox clusters. Matters should be improved with wider taxon sampling along with a clearer understanding of how duplicated genes evolve. © 2010 Landes Bioscience and Springer Science+Business Media.