Genetic diversity in a Brazilian bovine herd based on four microsatellite loci

Microsatellites or short tandem repeats (STRs), DNA markers relatively abun dant in the genome, have a high degree of polymorphism and therefore great potential for characterizing populations. The present study estimates genet ic variability in a set of four microsatellites (BMS3013, BMS3004, HEL10 an d TGLA122) in a Brazilian hybrid bovine breed (5/8 Aberdeen Angus x 3/8 Nel ore). The objectives were to determine the effect of crossbreeding and sele ction in these animals' genetic diversity as well as to discover the herd's genetic relationship with that of other breeds. Low diversity was verified in BR/IS3013 and high diversity was detected in BMS3004, HEL 10 and TGLA12 2. Two alleles in TGLA 122 are described here for the first time (TGLA122*1 55 and TGLA122*163). These genes are possibly characteristics of Zebu anima ls since they have not been found in other taurine samples so far investiga ted. Low interpopulational diversity was observed among taurine cattle popu lations, and clusters obtained on TGLA 122 phylogenetic trees agreed with t he bovine herd's geographic origin. Therefore, despite TGLA122's high polym orphism and high levels of intrapopulational diversity, the system engender s consistent bovine phylogenies. We detected an intriguingly high similarit y between Brangus Ibage and Red Angus since the former is a hybrid having 3 /8 of Nelore genes. Either these animals' environment or genetic selective practices applied to the breed probably favor the Angus genotype.