Identification of RAPD and SCAR markers associated with yield traits in the Indian tropical tasar silkworm Antheraea mylitta drury

Genetic analysis of Canarium album in different areas of China by improved RAPD and ISSR

To lay the foundation of the classification of Canarium album (C. album), and C. album from Terminalia Chebula (T. chebula) in different areas of China, improved RAPD and ISSR analysis were performed to analyze polymorphism and genetic relationship. Ten samples were collected from different locations in China. A total of 221 fragments were detected by improved RAPD, out of which polymorphic fragments accounted for 82.3% with average amplification bands of 10.05 per primer. ISSR markers revealed a total of 147 alleles, where polymorphic fragments accounted for 83.5%, with average amplification bands of 7.35 per primer. The sizes of fragments ranged from 200 to 2500bp and from 150 to 2000bp in RAPD and ISSR markers, respectively. The similarity coefficient ranged from 0.46 to 0.86 with RAPD markers and 0.36 to 0.89 with ISSR markers. The results indicated that improved RAPD and ISSR methods are useful for genetic diversity study of C. album. Thus, this study provides us the theoretical basis for the breeding and classification of C. album in South and Southwest China.

Genetic characterisation of microsporidia infecting Indian tasar silkworm, Antheraea mylitta, using morphology and molecular tools

The utility of inter simple sequence repeat-PCR (ISSR-PCR) assay in the genetic characterisation and elucidation of the phylogenetic relationship of different microsporidian isolates infecting tropical tasar silkworm, Antheraea mylitta Drury, is demonstrated. A total of 22 different microsporidians collected from the diseased tasar silkworms from Jharkhand state of India were analysed using morphological characters and ISSR-PCR. Observations spores under phase contrast microscope revealed oval to elongate in shape with length ranging from 3.8 μm to 5.1 μm and width from 2.6 μm to 3.3 μm. All the microsporidian isolates except MIJ-1gC showed gonadal infection and transovarial transmission in infected tasar silkworms. Fourteen out of 20 ISSR primers tested generated reproducible profiles and yielded a total of 281 fragments, of which 273 were polymorphic (97%). The degree of banding pattern was used to evaluate genetic distances and for phylogenetic analysis. The results demonstrated that ISSR analysis may be a useful and efficient tool for taxonomical grouping and phylogenetic classification of different microsporidians in general.