ABSTRACT
Antheraea assamensis Helfer, popularly known as Muga silkworm, the golden silk producer of Northeast India, is economically important and unique among the Saturniid silkworms. Muga silkworm is said to exhibit three semi-domesticated morphs i.e. green, blue, orange and one wild morph. In this study, the genetic diversity and phylogeny among the morphs of Muga silkworm collected from various geographical locations of Northeast India were investigated using RAPD and internal transcribed spacer DNA1 (ITS1) sequences. Thirty random primers generated 192 discrete bands; 123 of them were polymorphic (64.062%). The average amplicon per primer was found to be 6.4. In RAPD analysis, a wide range of genetic distance i.e. 0.0544-0.6228 was observed among the morphs. In the ITS1 sequence analysis, 35.35% of polymorphism and a range of genetic distance from 0.0024 to 0.2349 were observed. The phylogenetic trees based on RAPD and ITS1 sequences comprised of two major clades. The first clade comprised of the semi-domesticated morphs while the second clade included the wild morphs of different geographical origin. The information generated in this study can be used for conservation of the Muga silkworm through effective breeding programs
ABSTRACT
Antheraea assamensis Helfer, popularly known as Muga silkworm, the golden silk producer of northeast India is economically important and unique among the Saturniid silkworms. In this study, the genetic diversity and phylogeny of semidomesticated and wild morphs of Muga silkwormcollected from different geographical locations of northeast India were investigated based on the sequences of five mitochondrial loci, i.e. 12S rRNA, 16S rRNA, CoxI, Cytb and CR. All the five mitochondrial loci showed a strong bias towards higher ‘A’ and ‘T’ contents. Transitional substitutions were found to be more than the transversional substitutions. The rate of nucleotide substitution and average genetic divergence were found to be highest in CR sequences and lowest in 12S rRNA gene sequences among the morphs of Muga silkworm. The morphs collected from same geographical area had identical 12S rRNA, 16S rRNA, CoxI and Cytb gene sequences. Moreover, the 12S rRNA and 16S rRNA gene sequences of somesemi-domesticated and wild morphs collected from different geographical locations were also found to be similar. In the phylogenetic trees generated based on themitochondrial loci, mixing of semi-domesticated and wild morphs was observed as they shared the same group. The information generated in this study will help in formulating strategies to conserve the natural biodiversity present among these unique silkworms in northeast India. In addition, this will be useful in identifying diverse morphs of Muga silkworm, which will help in effective breeding programmes to improve its productivity.