Sequence analysis of mtDNA COI gene and molecular Phylogeny of Parasitic Unionicolid Mites (Acari: Unionicolidae: Unionicola) in China

Abstract

A nucleotide sequence analysis of cytochrome oxidase I (COI) gene fragment from parasitic unionicolid mites is performed in this paper. The aligned nucleotide fragment is 664bp (including gaps) in length, including 374 conserved sites, 284 variable sites, 73 conversion sites, 51 transpose sites. The conversion sites are much higher than the transpose sites with a conversion transpose ratio (si/sv) of 1.4. The percentages of A+T and G+C are 64.6% and 35.4% in the nucleotide sequence which indicates a strong AT bias. From the sequence analysis of COI gene, the relationship between Unionicola chelata and Unionicola arcuate are the farthest among all the parasitic unionicolid mites while the relationship between Unionicola ischyropalpus and U.arcuata are the closest. Using U.crassipes as an outgroup, the phylogenetic trees are reconstructed with maximum likelihood(ML) and neighbor-joining(NJ) inferences (PAUP4.0b10 tool), and the results show that U.arcuata is the more evoluted speciesand Unionicola agilex might be the first separated from ancestral species.