Assocıatıon between growth hormone gene polymorphısm and some growth traıts in Akkaraman and Anatolian Merino sheep

Background: There is a strong relationship between growth traits and genes. Identifying genotypes associated with superior phenotypic traits allows for targeted selection, facilitating the development of herds with desirable features. The growth hormone (GH) gene plays a crucial role in growth, development, and metabolism, making it a key focus for growth trait studies in livestock. Methods and results: This study investigated the relationship between polymorphism in the GH gene and growth traits in 33 Akkaraman and 40 Anatolian Merino ewes. Traits such as birth weight (BW), weaning weight (WW), and 6-month weight (LW6), as well as body measurements (withers height (WH), rump height (RH), body length (BL), chest width (CW), chest circumference (CC)), were collected. Average daily weight gain (ADWG) and Kleiber ratios were calculated. Polymorphisms were detected through PCR–RFLP using the HaeIII enzyme, identifying three genotypes: AA, AB, and BB. Statistically significant differences were found between genotypes for WW, RH, WH, BL, CW, and CC (P < 0.05). Sheep with the AA genotype had higher averages, while AB individuals exhibited lower values for these traits. ADWG1 and KR1 values were higher in homozygous genotypes (AA and BB) than in heterozygous ones (AB), showing statistical significance (P < 0.05). Conclusions: These results suggest that the GH gene may serve as a candidate for Marker-Assisted Selection (MAS) in Akkaraman and Anatolian Merino sheep, particularly for growth-related traits.