A Study on Polymorphisms in Five Markers MR1-MR5 of Pit-1 Gene and Their Effects on Growth Rate and Carcass Traits in Egyptian Domestic Chickens

Chicken Pit-1 gene could be a candidate locus that affects important economic production traits. So, the present work was conducted to detect and analyze the different patterns (genotypes) in five reported polymorphisms (MR1-MR5) of such genes and investigate their effects on growth rate and carcass characteristics (Breast and thigh weights) in five different chicken breeds (Fayoumi, Dokki-4, White Leghorn, El-Salam and Inshas). Blood samples were collected from five breeds. DNA was isolated, and different patterns for MR1 and MR2-MR5 were analyzed by simple-PCR and PCR-RFLP, respectively. Sequence analysis and alignment of different detected patterns were performed. The results detected several patterns in five markers MRI-MR5 of the Pit-1 gene, two different types in MR1, MR2, MR4 and MR5, and four types in MR3. Sequence analysis identified various single nucleotide polymorphisms (SNPs) in MR patterns generating heterozygous and homozygous genotypes. Except for MR2, heterozygous genotypes were strongly associated with improving growth rate and carcass characteristics in some chicken breeds of MR1, MR3, and MR5 and all five breeds of MR4 as compared to homozygous genotypes. However, the results clarified a positive relationship between homozygous genotypes and improving the economic production traits in some breeds of MR1, MR3, and MR5 and all breeds of MR2 with respect to heterozygous genotypes. The present investigation proved that the detected SNPs in different patterns of the Pit-1 gene could be beneficial markers for selection of Egyptian chicken breeds for enhancing the growth rate and carcass characteristics. On the other hand, some homozygous genotypes are helpful in the successful breeding program. Therefore, the use of Pit-1 variations can be valuable for improving the important productivity traits in the chicken.