Ancestrally-duplicated paraHOX gene clusters in humans

A paraHox gene cluster has been described recently in Amphioxus. We show he re using bioinformatics and cytogenetics that, as the probable result of th e duplication of an ancestral paraHox gene cluster, human paraHOX genes are located in four paralogous regions of the genome, on chromosomes 4, 5, 13 and X. By analogy with the four HOX gene clusters, we propose to designate the four paraHOX gene clusters as paraHOX-A to D clusters. We also propose a scenario for the evolution of HOX and paraHOX genes. Several chromosomal translocation breakpoints of hemopathies are located in the paralogous regi ons that contain the paraHOX genes. Two of the paraHOX genes are involved i n these rearrangements.