[Phylogenetic reconstruction of DNA polymerase X family]

Phylogeny within DNA polymerase X family requires a re-examination as the expansion of family members, particularly considering the enter of two entomopoxvirus(EPV) members. A total of 37 DNA polymerase core-domain sequences(SMART domain), which come from numerous species with different evolutional levels, including above two virus members, were analyzed. The result showed that, the phylogenetic relationship within this family basically assorted with the distribution status of used species, of which two virus members and DNA polymerase beta(pol beta) of eukaryote were clustered together into sister group, indicating the likelihood that the two entomopoxviruses originated from eukaryote. The divergence time of subgroups, similarity of gene structure and conservation of syntenic genes were also analyzed, and evidences showed that, DNA polymerase mu (pol mu) is only present in Mammals, and as a recently occured duplication-gene of terminal deoxynucleotidyl transferase(TdT).