Preliminary investigation on phylogenetic relationship among three common species of house dust mites

Dermatophagoides farinae, D. pteronyssinus and Euroglyphus maynei were used for the investigation. The cDNA fragment coding for Der f 1 and Der f 2 were amplified by PCR, cloned and sequenced. By bioinformatics softwares, the amino acid sequences for Der f 1 and Der f 2 were deduced and compared with those for the groups 1 and 2 allergens of D. pteronyssinus and E. maynei available in GenBank. Amino acid sequence similarity analysis showed that Der p 1 shared 84% identical residues with Eur m 1 and 83% with Der f 1. Similarly, Der p 2 shared 87% identical residues with Eur m 2 and 68% with Der f 2. In the two phylogenetic trees constructed with group 1 and 2 allergens, D. pteronyssinus was clustered with E. maynei but not with D. farinae, although D. pteronyssinus and D. farinae belong to the same genus. D. pteronyssinus should be more similar to E. maynei than to D. farinae at evolutional level, which was not consistent with the conventional taxonomical relationship based on their morphological characteristics.