High variability of the BoLA-DRB3 gene in Crioula Lageana cattle.

The Bovine Leukocyte Antigen (BoLA) is one of the most important immunologic and genetic components of susceptibility or resistance to disease for cattle. The BoLA-DR region contains the monomorphic locus BoLA-DRA and three BoLA-DRB loci, with the BoLA-DRB3 gene being the most expressed and polymorphic. Its high variability benefits immunological responses against several diseases. This study aims to assess the genetic diversity and variability of the BoLA-DRB3 gene in the Crioula Lageana cattle breed and compare it with other locally adapted and commercial cattle breeds. DNA samples from 208 animals were used to genotype the second exon of this gene using the PCR-SBT technique, to determine the variability of BoLA-DRB3 in this cattle breed. The raw DNA sequences were analyzed using the Assign 400ATF ver.1.0.2.41 software. Principal component analysis (PCA) evaluated the relationship between the Crioula Lageana breed and other cattle breeds. Forty-four alleles were identified in the Crioula Lageana breed, resulting in an expected heterozygosity of 0.95. Statistical analysis demonstrated that this population is in Hardy-Weinberg equilibrium. PCA revealed the proximity of this breed to other Criollo cattle breeds. Future studies are necessary to evaluate the role of the BoLA-DRB3 gene polymorphisms detected in the adaptation of the Crioula Lageana, as well as to determine the BoLA haplotypes present in this native breed. The Crioula Lageana breed, despite its small population, maintains a high variability for the BoLA-DRB3 gene, which contributes to the preservation of desirable immunological characteristics.