Molecular Characterization of Selective indigenous, Cross-bred and Exotic Cattle Using RAPD Markers

Abstract

The research work was conducted at Animal Cell Culture and Molecular Biotechnology Laboratory, Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna, Bangladesh. The major objective of the study was to find out the genetic variation and to determine the genetic distance among selected cattle population of Bangladesh. DNA was extracted from experimental cattle blood samples and the extracted DNA was observed by gel electrophoresis. Random Amplification of Polymorphic DNA analysis was carried out using DNA samples of experimental cattle. Only distinct, reproducible and scorable polymorphic fragments were taken into consideration for analysis. Twelve primers were used in RAPD analysis. Two different primers generated 106 bands of which 95 (90.48%) were polymorphic and 10 bands were common in nature. The frequencies of polymorphic bands varied from primer to primer. Though no sample-specific marker was identified, the high level of polymorphism revealed by the proportion of polymorphic loci (90.48%) indicated that RAPD markers could be considered as one of the effective tools for estimating genetic diversity. Dendrogram grouped the cattle into two major clusters: cluster (I) and (II). Again cluster (II) was subdivided into IIA and IIB, and showed genetically similar characteristics. The values of pair-wise comparisons of Nei's genetic distance among experimental cattle genotypes were computed from combined data sets for the two primers. Comparatively higher genetic distance (0.82) was found between AFSL-1360 and Sahiwal-586. The lowest genetic distance (0) was revealed between Freshian-75%-1630, AFSL-1160 and Freshian-75%-1781, Freshian-62.5%-2000. The range of genetic distance of experimental genotypes and the difference between the highest and lowest genetic distance indicated the presence of variability among the experimental genotypes of cattle. The genetic diversity of local cattle is relatively higher for a prescribed breed and therefore, has opportunities to improve those using selective crossbreeding techniques for future improvement of local cattle to yield high milk and meat products.