The Intraspecific Genetics Of Antheraea Pernyi And Interspecific Genetics Of The Genus Samia Based On Mitochondrial DNA Sequence

China is rich in wild silkworm resources,and the wild silkworm industry is an important characteristic agricultural industry in China.Analysis of the mitochondrial genome of wild silkworm is of great significance to classification of variety groups and breeding of wild silkworm resources.In this study,the mitochondrial genomes of 16 Antheraea pernyi varieties were determined,together with 8 previous published mitochondrial genomes,and the mitochondrial genomes of 24 varieties were further analyzed to explore their genetic diversity and intraspecific phylogeny.The phylogenetic framework of the genus Samia was also constructed based on 67 COI sequences of 13 Samia species,to reveal the phylogenetic relationship between Samia cynthia and Samia ricini.The main results are as follows:1.The mitochondrial genomes of 24 varieties of Antheraea pernyi are 15563～15573 bp in length,and contained 37 genes(13 PCGs,22 t RNAs,2 r RNAs)and one A+T rich region.The structure is highly conserved and no gene translocation occurred.The A+T rich region of these mitochondrial genomes all contain 6 tandem repeat units.A total of 238 SNVs were identified in the mitochondrial genome of 24 A.pernyi varieties,accounting for 1.53%,indicating that the degree of genetic differentiation among varieties is low.Cytb gene is the most variable gene in the mitochondrial genome of A.pernyi.Both the phylogenetic analysis and genetic distance analysis based on the whole mitochondrial genome support that these 24 varieties of A.pernyi used are derived from 2 lineages,named as Qinghuang 1 Lineage and Yuzao 1 Lineage,respectively.2.The mitochondrial COI gene sequences corresponding to DNA barcodes from 13 Samia species were analyzed,and a DNA barcode-based phylogenetic framework for these Samia species was provided.The mixed clustering relationship between individuals of S.ricini and S.canningi suggested that the cultivated silkworm S.ricni be derived from the noncultivated silkworm S.canningi.The remote phylogenetic relationship indicated that S.ricini and S.cynthia are distinct species,thus providing molecular evidence that they had entirely independent origins.This is the first study to assess the DNA barcodes of the genus Samia,which provides the first molecular phylogenetic framework for Samia species.