SSR marker based DNA fingerprinting and diversity study in rice (Oryza sativa. L)

The genetic diversity and DNA fingerprinting of 15 elite rice genotypes using 30 SSR primers on chromosome numbers 7-12 was investigated. The results revealed that all the primers showed distinct polymorphism among the cultivars studied indicating the robust nature of microsatellites in revealing polymorphism. Cluster analysis grouped the rice genotypes into 10 classes in which japonica types DH-1 (Azucena) and Moroborekan clustered separately from indica types. Principal component analysis was done to visualize genetic relationships among the elite breeding lines. The results were similar toUPGMA results. Based on this study, the larger range of similarity values for related cultivars using microsatellites provides greater confidence for the assessment of genetic diversity and relationships. The information obtained from the DNA fingerprinting studies helps to distinctly identify andcharacterize 9 varieties using 18 different RM primers. This information can be used in background selections during backcross breeding program

Investigation of monocrotophos toxic effects on human lymphocytes at cytogenetic level

The genotoxic and cytotoxic effects of monocrotophos, an organophosphate insecticide, was investigated on human lymphocytes cultured in vitro. Utilizing the trypan blue dye exclusion technique assay the IC50 (half maximal inhibitory concentration) of monocrotophos was found to be 16 M. Based on IC50 value, monocrotophos was found to be highly toxic to lymphocyte culture. Chromosomal aberrations induced by monocrotophos were determined using karyotyping. The analysis revealed that more satellite associations, breaks and gaps were found which were statistically significant (P < 0.05) when compared to controls. Comet assay was used to assess the possibility of monocrotophos induction of DNA damage where the increase in comet tail length relates to the extent of DNA single strand breaks. These results indicate that in vitro assays could be used as indicators of cyto- and genotoxic effects of the pesticide on humans, and their end points could be used as biomarkers