Single nucleotide polymorphisms of GDF9 gene/exon 2 region and their associations with milk yield and milk content traits in Karakas and Norduz sheep breeds

Karakas and Norduz sheep have been adapted to the Lake Van region of Turkey for many years as being domestic genetic resources and meat, milk, and fleece traits are a reliable economic resource especially preferred by small family businesses around the area. In this study, the data set consisted of milk yield (MY) and milk content components; milk fat (MF), fat-free dry matter (FFDM), dry matter (DM), protein (Pro), lactose (Lac), pH, acidity H (aH), and lactic acid (Lac). Besides, Karakas (n = 30) and Norduz (n = 26) sheep were chosen to investigate based on the SNP method. Correspondingly, genomic DNA from both breeds exon 2 of the GDF9 gene region was amplified, 815 base pairs (bp) in length, by means of PCR. Therefore, there were three noval SNPs detected in both breeds under investigation. Although SNP1 and 2 with genotypes of GG and AG had statistically significant impacts on both milk production and milk components (p < 0.01), SNP3 with genotypes of TT, TC had no significant effects on the milk characteristics in question.