Application of the Restriction Landmark Genome Scanning (RLGS) method for analysis of genetic diversity between Asian and African sorghum.

Restriction Landmark Genome Scanning (RLGS) used to detect large numbers of restriction landmarks in a single experiment and applied to analyze the genetic diversity of Asian and African sorghum accessions. This method is one of the genome analysis tools based on the concept that restriction enzyme sites can serve as landmarks throughout a genome. RLGS uses direct end-labeling of the genomic DNA digested with a rare-cutting restriction enzyme and high-resolution two-dimensional electrophoresis. It has an advantage of providing precise information on a spot intensity that reflects the copy number of restriction landmarks and to visualize differences in methylation levels across the genome. RLGS becomes very useful for doing whole genome scans that equals the work of thousands of polymerase chain reactions. A study was carried out using Sorghum accessions collected from countries viz., Morocco, Nigeria, Sudan, South Africa, Japan, South Korea, and China. One representative sample was chosen from a country for analysis carried out at National Institute of Agrobiological Sciences (NIAS). Two dimensional spot images for seven accessions obtained and spot intensities were scanned. Totally, 119 spots were detected of which 95 spots observed as polymorphic and 24 as non polymorphic. Unique presence and null spots were specifically detected in all accessions taken for study. A total of 37 unique spots and 12 null spots, detected in this experiment. Principal Coordinate Analysis indicated, four African accessions scattered in the diagram were diverse and three Asian accessions closely distributed with narrow diversity. The phylogenetic tree showed that Sudan and Nigerian accessions were distant while Chinna, Japan and Korea accessions had close proximity.