Full Length Research Paper

Mitochondrial DNA analysis reveals a low nucleotide diversity of Caligula japonica in China

Yu-Ping Li^1g, Bao-Shan Yang^1,2g, Huan Wang¹, Rui-Xi Xia¹, Lin Wang³, Zhi-Hong Zhang¹, Li Qin¹ and Yan-Qun Liu¹*

¹College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110161, China.

²School of City Development, University of Jinan, Shandong, Jinan 250002, China.

³Technical Center for Inspection and Quarantine, Beijing Entry-Exit Inspection and Quarantine Bureau, Beijing 100026, China.

*Corresponding author. E-mail: liuyqlyp@yahoo.com.cn. Fax: 86-24-88411127.

^gThese authors contributed equally to this work.

Accepted 14 April, 2009

Caligula japonica (Lepidoptera: Saturniidae), an endemic species in Eastern Asia, is not only an economically important pest to be controlled, but also a producer of expensive silk. We have demonstrated previously the presence of a higher genetic diversity and a certain degree of genetic differentiation related to geographical distribution in C. japonica based on RAPD and ISSR markers. In this paper, we determined the 574 bp segment of the mitochondrial cytochrome oxidase subunit I (COI) gene sequences of C. japonica in China to assess nucleotide sequence diversity (GenBank accession no. FJ358506-FJ358517). The pairwise COI sequence identity between these samples reached 99 - 100%, showing a low nucleotide sequence diversity (Pi = 0.0035). In NJ tree, these samples were divided well into Northern and Southern group, which was consistent with that previously reported based on RAPD and ISSR markers and suggested the genetic differentiation between them might have been occurred. Further work is needed to define the genetic structure of different populations of C. japonica.

Key words: Caligula japonica, mitochondrial DNA, COI, genetic diversity, China.