Estudos genômico-moleculares para características morfométricas e de variabilidade gênica em equinos

Abstract

The low genetic variability can cause several productive and reproductive prejudices in horses. Genetic recombination processes, such as crossing-over, can increase genetic variability by promoting changes between parts of homologous chromosomes during meiosis. Among the proteins involved in crossing-over, we highlight the role of PRDM9, which determines DNA sequence hotspots through a key structure called zinc fingers (ZF). Modifications in the sequences of these ZF promote the recombination of different hotspots along the DNA. Thus, this study aimed to describe the diversity of ZF arrangements and allele distribution of the PRDM9 gene in 26 horse breeds. To obtain the DNA, hair samples from 95 animals were used. Amplification of the gene of interest was performed using specific primers and the amplification products were qualified, quantified and then sequenced. For the analysis and identification of polymorphisms, the sequences obtained were visualized using CodonCode Aligner programs. A total of 14 new ZF domains, 19 alleles and 19 genotypes were found. Allele 1 as well as its homozygous genotype (1|1) showed higher frequencies (0.889 and 0.775, respectively). The results allow better matings, it permits to choose animals whose PRDM9 genotype is less frequent in populations with little genetic variability. It promotes new recombinations and helps to increase variability. Moreover, the gene plays an important role in the evolutionary process, and this information may contribute to a better understanding of this mechanism.