Bovine DNA polymorphisms uncovered by RAPD-PCR

Random amplification of polymorphic DNA by the polymerase chain reaction (RAPD-PCR), using arbitrary 10-bp oligonucleotide primers was assessed in 24 young elite bulls selected for progeny testing and, 10 cows. RAPD-PCR amplification patterns were analyzed to identify polymorphic bands among animals within and between groups. Duplicate PCR reactions for each animal were earned out in 1X Tricine buffer, 15/30 ng of primer and 20 ng of genomic DNA for 51 cycles. Amplification products were separated by agarose gel (1.4%) electrophoresis and detected by ethidium bromide staining. Forty primers were screened and 18 of them were selected for further use because of their consistent PCR amplification patterns and large number of amplified bands. An average of 9.66 bands and 10.3 bands per primer was obtained for the elite young bull and cow groups respectively. Amplified bands ranged from 0.2 Kb to 5 Kb in size. The cow group double (2.1) the average number of polymorphic bands per primer when compared to the young elite bull (1.0) group. Frequencies of dominant polymorphic bands range from 75 to 95% for different primers. Similarity indexes among animals, based on the band sharing method, varied from 0.76 to 1.0. The reduced band polymorphisms found in the elite young bull group is probably due to the intensity of selection applied to this group of animals when compared to the cow group. The trend observed is in agreement with the theoretical expectation of a higher level of homozygosity in the elite young bull group than in the cow group.