[Characterization of the thermal shock gene (HSP-70.1) and its relationship with production characteristics in dairy cattle reared in the Brazilian semiarid]

ABSTRACT The objective of this work was to evaluate the genetic diversity of the HSP-70.1 gene and to associate the polymorphisms found with the performance of Holstein, Girolando (5/8H-G) and Sindi dairy cows raised in region of the Brazilian semiarid. Polymorphisms were identified and evaluated using the PCR-RFLP technique using the EcoRII restriction enzyme. Genetic variability was evaluated using the standard diversity index and molecular variance analysis (AMOVA). The identified polymorphisms were evaluated on the characteristics of milk production. They were identified from the seven alleles, demonstrating that there was polymorphism for the analyzed gene region and some alleles were shared among the herds. The Holstein and Sindi bovine breeds were genetically like the analyzed gene. AMOVA demonstrated that there is genetic variation between and within the herds, with most of the variation occurring within the herds for all groups evaluated. There was effect of the alleles identified on the production of milk herds of Holstein and (P<0.0001) Girolando (P<0.0117) breeds. The HSP-70.1 gene was polymorphic in the population of dairy cattle studied, and therefore a promising molecular marker to evaluate milk production of breeds created in semiarid regions.

摘要 本研究旨在评估热休克蛋白70.1（HSP-70.1）基因的遗传多样性，并将所发现的多态性与饲养于巴西半干旱地区的荷斯坦（Holstein）、吉罗兰多（Girolando，5/8H-G）及辛迪（Sindi）奶牛的生产性能进行关联分析。本研究采用PCR-RFLP技术，以EcoRII限制性内切酶对多态性进行鉴定与评估；遗传变异分析则采用标准多样性指数及分子方差分析（AMOVA）。研究共鉴定出7个等位基因，结果表明所分析的基因区域存在多态性，且部分等位基因在各牛群间共享。荷斯坦与辛迪牛品种在本次分析的基因区域上遗传特征相似。分子方差分析结果显示，所有评估组的牛群间及牛群内均存在遗传变异，且绝大多数变异来源于牛群内部。所鉴定的等位基因对荷斯坦奶牛群的泌乳性能具有极显著影响（P<0.0001），对吉罗兰多奶牛群的泌乳性能具有显著影响（P<0.0117）。本研究涉及的奶牛种群中，HSP-70.1基因存在多态性，因此可作为评估半干旱地区养殖奶牛品种泌乳性能的潜在分子标记。