Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and random amplified polymorphic DNA (RAPD) based genetic variation studies in eri silkworm (Samia cynthia ricini Lepidoptera: Saturniidae)
Four strains of eri, Samia cynthia ricini Lepidoptera: Saturniidae that can be identified morphologically and maintained at North East Institute of Science and Technology, Jorhat were characterized based on their protein profile by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and DNA by random amplified polymorphic DNA (RAPD) technique. Fiber yield was highest in Gs strain. SDS-PAGE profile showed 11 prominent bands in the strains with molecular weight ranging from 35 to 200 kDa together with 28 minor bands with molecular weight ranging from 33 to 210 kDa. Two polypeptides of molecular weight 90 and 110 kDa were absent in both Y and Ys. Eight random primers and one universal primer used for RAPD analysis generated a total of 79 bands, of which 49 were polymorphic. In both SDS-PAGE and RAPD, the UPGMA based dendrogram showed two clusters: cluster 1 included Gs and G, whereas Y and Ys was grouped in cluster 2 by SDS-PAGE analysis but RAPD analysis grouped Ys and G in cluster 1 and Gs and Y in cluster 2. The range of genetic diversity observed among the strains affirms the potentiality of RAPD technique for identification and selection of distant parents for silkworm hybridization for high silk yield.
Key words: Genetic variation, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), random amplified polymorphic DNA (RAPD), silkworm, cocoon.