Genotyping of TSH-β GENE G 141A associated with some productive and physiological traits of local Iraqi chicken

This study aimed to detect the SNP G 141A of the TSH-β gene and to discuss their association with some physiological and productive traits in local Iraqi chicken. For this purpose, 100 local Iraqi chickens at 67 days of age were placed in individual cages, and their egg quality measurements were done from 2021 to 2022 to detect the different genotypes. The traits were measured from the sexual maturity up to 100 days for each chicken. The blood samples were collected from 100 chickens at 38 weeks from their brachial vein. PCR REFLP method was used and the PCR product was digested by MSP1 endonuclease enzyme to detect G141A SNP. Three genotypes were detected viz. GG genotype (wild), GA genotype (heterozygous), and AA genotype (mutant). The G allele frequency was 0.865 compared to the A allele (0.135). There was a significant effect (P 0.05) of the AA genotype of the TSH-β gene on egg mass, followed by the GG genotype and then the GA genotype in period 2. The AA genotype had a significant effect on yellow height, weight, and diameter, and albumin weight, diameter, and height.