Study of CAST and GH gene polymorphisms in kazakh fat-tailed sheep

The paper presents the results of a molecular genetic analysis of polymorphisms at the GH-HaeIII and CAST-MspI loci in Kazakh black-tailed rough-haired sheep bred in farms “Razakhun” in Zhambyl region and “Tokan” in Zhetysu region.
The purpose of the study is to study the genetic structure of populations and identify the distribution of genotypes and alleles associated with productive traits.
Genotyping was performed by PCR followed by restriction analysis (PCR-RDF). It was found that the GH-HaeIII locus is characterized by an extremely low level of polymorphism: the A allele was almost completely fixed in all the studied groups, while the CAST-MspI locus demonstrated a higher degree of allelic diversity, especially in the “Razakhun” farm population.
Statistically significant differences in genotype distributions, heterozygosity indices, fixation coefficients, and deviations from Hardy — Weinberg equilibrium were observed. The findings highlight the value of the CAST locus as an informative marker for assessing genetic diversity and supporting breeding program design. These results may serve as a basis for the further implementation of genetic markers in selective breeding programs for sheep in Kazakhstan

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