Uncovering genetic markers for growth and fat-tail traits in Kurdi sheep: associations with DGAT1 and PPARGC1B variants.

BACKGROUND: Improving meat quality and production traits in indigenous livestock is crucial for food security and sustainable agriculture. This study investigated polymorphisms in the DGAT1 and PPARGC1B genes and their associations with growth and fat-tail traits in Kurdi sheep. METHODS: Following DNA isolation using the modified salting-out method, a total of 120 Kurdi sheep were genotyped for DGAT1 and PPARGC1B using PCR‑SSCP and targeted sequencing. Then, the resulting sequences were assessed by bioinformatics software. Association analyses were performed using a linear mixed model in SAS 9.4. RESULTS: Using PCR-SSCP and targeted sequencing techniques, we identified a previously reported silent mutation (233 C > T) in DGAT1 (exons 16-17) with allele frequencies of 68.5% (C) and 31.5% (T). For PPARGC1B (intron 6-7), two novel polymorphisms (C.600 + 747 T > C and C.610 + 38 G > A) were detected at positions 52 (genotypes CC, TC, TT) and 300 (genotypes AA, AG, GG) with frequencies of 49%, 45%, and 6%, respectively. Association analysis revealed that DGAT1 genotypes significantly influenced birth weight (P < 0.05). Notably, PPARGC1B polymorphisms showed significant associations with live weight and lower fat-tail circumference (P < 0.05). Moreover, birth year and birth type significantly affected several growth and fat-tail measurements (P < 0.05). CONCLUSION: These findings provide the first evidence linking PPARGC1B variants to fat-tail traits in Kurdi sheep. The identified associations suggest that both DGAT1 and PPARGC1B loci could serve as potential genetic markers for improving growth performance and fat-tail characteristics in breeding programs for Kurdi sheep.