Survey of Hox genes in the skate, Raja egalanteria

It is postulated that gene duplications potentiate the acquisition of morphological innovations. Duplication of the Hox gene clusters has been implicated in the evolution of diverse vertebrate body plans. Information on the number and organization of Hox gene clusters from selected vertebrate clades is essential for a better understanding of the role of Hox gene clusters in the vertebrate radiation. We have cloned homeobox sequences by PCR survey from the skate (Raja egalanteria). Clones were assigned to specific Hox cognate groups (vertical paralogs) on the basis of nucleotide and derived amino acid sequence. One hundred eighty two clones were examined and assigned to 25 cognate groups. Analysis of the dataset indicates the presence of multiple Hox clusters in this species. The precise Hox cluster number cannot be determined by this analytical approach, but three or more clusters are indicated provisionally.