Genetic diversity of -casein () and lactoferrin () genes in the endangered Turkish donkey () populations.

In this study, the -casein () and lactoferrin () genes which were found in association with milk production traits in different animal species were studied firstly in Turkish donkey populations. A total of 108 donkeys from different regions of Turkey were used in order to reveal the different genotypes of and genes by using polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. To determine the genetic polymorphism, we attempted to digest a fragment of 235 bp of the gene and a fragment of 751 bp of the gene using I, and II, I and I restriction enzymes, respectively. Neither the gene nor the gene had enzyme recognition sites with the I, II and I restriction enzymes in all of the studied samples. However, the gene was only distinguished with the I restriction enzyme. Three genotypes were identified in the gene with the I restriction enzyme: GG homozygotes (667, 84 bp), AG heterozygotes (751; 667, 84 bp) and AA homozygotes (751 bp). The transition from guanine to adenine in 89 bp of the gene lacks the restriction site and different genotypes are obtained. This novel single nucleotide polymorphism (SNP) has been firstly detected in donkeys. According to the results, the G allele was predominant in the I gene in the studied Turkish donkey populations. In this study, all the genotype distributions of I were not found in Hardy-Weinberg equilibrium ( ). The and genes have not been studied before in donkeys, so the results are the preliminary results of these gene regions in donkeys.