Genetic polymorphism of some genes related to reproductive traits and their association with calving interval in Egyptian buffalo

This study aimed at detecting genetic polymorphisms in the reproductive candidate genes follicle-stimulating hormone receptor (FSHR), insulin-like growth factor1 (IGF-1), insulin-like growth factor1- receptor (IGF-1R), inhibin beta-A (INHBA), and signal transducer and activator of transcription5 (STAT5A) and establish their association with calving interval (CI) as an early predictor of the reproductive efficiency of fertility status. Genomic DNA was extracted from whole blood of unrelated Egyptian buffalo females. The PCR products of investigated genes were subjected to single-strand conformation polymorphism analysis. The results illustrated that the FSHR gene locus showed three polymorphic patterns with 61.4% for pattern1, 21.4% for pattern2 and 17.2% for pattern3. The IGF-1 gene locus had two polymorphic patterns with 84.3% for pattern1 and 15.7% for pattern2. IGF-1R gene locus had four polymorphic patterns with 50% for pattern1, 28.6% for pattern2, 15.7% for pattern3 and 5.7% for pattern4. The INHBA gene locus was monomorphic. The STAT5A gene locus had three polymorphic patterns with 91.4% for pattern1, 4.3% for pattern2 and 4.3% for pattern3. Correlations between the phenotypic data and the molecular results of genes studied revealed that: (a) pattern2 of FSHR gene locus recorded the lowest CI with prediction of 70% accuracy for the phenotype of high fertility; (b) IGF-1 gene locus had no impact on fertility; (c) IGF-1R gene locus predicted the phenotype of the high fertility with approximately 83.3% accuracy for pattern2; (d) INHBA gene locus had no impact on fertility and; (e) pattern2 of STAT5A gene locus was associated with high fertility, while pattern3 was associated with low fertility.