Polymorphisms of the Dopamine beta-hidroxylase gene and its association with bovine temperament

摘要

Temperament in bovines is defined as behavior in response to human handling and is influenced by the sympatheticadrenal system. The bovine Dopamine beta-hidroxylase (DBH) gene is located on chromosome 11 and codes for the Dopamine beta hidroxylase enzyme, essential por the synthesis of this neurotransmitter. Simple nucleotide polymorphisms (SNP) have been identified on exon 12, possibly associated with changes in bovine temperament. The aim of this study was to find polymorphisms in this region and associate them with temperament traits in BON (Blanco Orejinegro - Bos taurus taurus), fighting bulls (Bos taurus taurus) and Brahman (Bos taurus indicus) cattle breeds. A total of 80 individuals were used to evaluate chute behavior (CB) and flight speed (VS), and in 52 of them a 702bp fragment in exon 12 of the gene was sequenced, identifying 22 haplotypes. The mínimum number of haplotypes (4), the lowest nucleotide diversity (0,0012±0,0011) and the highest fixed loci number were found on fighting bulls. Moderate differentiation between the populations was observed with the lowest genetic distance (FST=0.03309) between Bos taurus taurus breeds. Differences in VS were observed (p0.05) being lower in BON males than in Brahman (1.45±0.61 and 2.02±0.74 respectively) and in Brahman females than in Fighting bull females (1.05±0.58 y 2.23±0.80 respectively). Even though no association with the genetic plymorphisms was found, a posible influence of selection in exon 12 is suggested which may influence in other behavioral characteristics.