A Study on Polymorphisms in Five Markers MR۱-MR۵ of Pit-۱ Gene and Their Effects on Growth Rate and Carcass Traits in Egyptian Domestic Chickens

Chicken Pit-۱ 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 (MR۱-MR۵) of such genes and investigate their effects on growth rate and carcass characteristics (Breast and thigh weights) in five different chicken breeds (Fayoumi, Dokki-۴, White Leghorn, El-Salam and Inshas). Blood samples were collected from five breeds. DNA was isolated, and different patterns for MR۱ and MR۲-MR۵ 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-MR۵ of the Pit-۱ gene, two different types in MR۱, MR۲, MR۴ and MR۵, and four types in MR۳. Sequence analysis identified various single nucleotide polymorphisms (SNPs) in MR patterns generating heterozygous and homozygous genotypes. Except for MR۲, heterozygous genotypes were strongly associated with improving growth rate and carcass characteristics in some chicken breeds of MR۱, MR۳, and MR۵ and all five breeds of MR۴ 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 MR۱, MR۳, and MR۵ and all breeds of MR۲ with respect to heterozygous genotypes. The present investigation proved that the detected SNPs in different patterns of the Pit-۱ 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-۱ variations can be valuable for improving the important productivity traits in the chicken.

Keywords:

Chicken breeds , Pit-۱ gene , PCR-RFLP , DNA sequencing , Economic traits