DNA Sequence Variation in the Tetranychus kanzawai Complex in Northern Hokkaido, Japan

DNA sequences of the internal transcribed spacer 1 (ITS1) of the nuclear ribosomal RNA gene and of mitochondrial cytochrome oxidase subunit I (COI) were analyzed for 13 Tetranychus kanzawai populations collected in northern Hokkaido, Japan. Five and 13 DNA haplotypes were found for ITS1 and COI, respectively, and the COI haplotypes were classified into 5 amino acid haplotypes. Monophyly of all haplotypes found in this study was strongly supported by bootstrap analysis, confirming that all analyzed individuals belonged to the T. kanzawai complex. The geographic distributions of these haplotypes overlapped, showing that populations had differentiated genetically from each other. However, some hybrid individuals were detected, indicating that genetic differentiation was not complete. Large genetic variation in the DNA sequences in the study area and the discovery of ancestral haplotypes strongly suggest that the complex originated in Northeast Asia.