Strains of Philosamia ricini Differ in their Mitochondrial 16S Ribosomal RNA and Cytochrome Oxidase Subunit I Gene Sequences

Philosamia ricini, the Indian eri silkworm, contributes significantly to the production of commercial silk and is widely distributed in the Brahmaputra valley of the North-Eastern India. Strains of P. ricini show wide variation in their phenotypic traits and are commercially exploited in these places because of their high silk yield potential. In this study, we have analyzed the partial mitochondrial 16S ribosomal RNA (16S rRNA) and partial cytochrome oxidase subunit I (CoxI) gene sequences to assess the genetic diversity among five different strains of P. ricini. Sequence analysis of mitochondrial 16S rRNA and mitochondrial CoxI genes showed variation among the strains. Except the Red cocoon variety, the sequence of the fragment of 16S rRNA gene was identical among White plain, White zebra, Blue plain and Blue zebra strains. Similarly, the sequence of the fragment of the CoxI gene grouped the strains into two distinct groups, (a) White plain and Red cocoon variety and (b) White zebra, Blue plain and Blue zebra strains. For the first time, the mitochondrial gene sequences of different strains of P. ricini have been studied.