Molecular Characterization of Selected Local Cattle Breeds Using RAPD Markers

Abstract

The study was conducted at Animal Biotechnology Cell Culture and Molecular Biotechnology laboratory of Biotechnology and Genetic Engineering Discipline, Khulna University, Bangladesh. DNA was extracted from 20 local cattle blood samples and the extracted DNA was observed by gel electrophoresis. Random Amplification of Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) analysis was carried out using DNA samples of local cattle. Only distinct, reproducible and scorable polymorphic fragments were taken into consideration for analysis. Two primers those used in RAPD analysis of 20 cattle amplified 95 different reproducible bands of which 72 (75.79%) were found to be polymorphic and 23 bands (24.21%) were found to be monomorphic 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 (83.33%) indicated that RAPD markers could be considered as effective tools for estimating genetic diversity in different samples of cattle. The dendrogram shows that all the animals were grouped into two major clusters I and II. Cluster I sub divided into I A and I B. Under cluster -II, Madaripur-I, 6, 7 and Sariatpur-l S, 20 were genetically similar. Therefore, they grouped into same cluster. Under cluster -1, Madaripur-2, 3, 4, 5, 8, 9 Faridpur-10, 11, 12, 13, 14, 15, 16 and Sariatpur-17, 19 showed same characteristics but different from cluster-I. Similarly sub-cluster-I.A Madaripur- 2,4,5,8,9; Faridpur-IO, 11, 12, 13, 14, 15, 16; Sariatpur-17were similar but were dissimilar from sub-cluster -IIB-Madaripur-8, 9. There was a high level of genetic variation among the studied samples of cattle as indicated by the proportion of polymorphic loci. Estimation of higher level of genetic variation in the breeds might be consistent with the fact that it is a highly polymorphic animal. The values of pair-wise comparisons of Nei's (1979) genetic distance among 20 cattle genotypes were computed from combined data sets for the 2 primers ranging from 0.00 to 1.00. Comparatively, higher genetic distance (1.00) was found among 14 (Madaripur-3, 9), (Faridpur- 11, 15), (Sariatpur-IS, 20) versus Madaripur-2, 5, 7, 9, Faridpur- 11, 12, 15 and Sariatpur-17, 18. The lowest genetic distance (0.00) was observed between Faridpur-15 and Madaripur-S. The range of genetic distance of 20 genotypes is (l.OO±O.OO) and the difference between the highest and lowest genetic distances indicated the presence of variability among the 20 genotypes of cattle. The genetic diversity of local cattle is relatively higher for a prescribed group of animal and therefore, have an opportunities to improve them using crossbreeding programme.