Investigation of Polymorphism in Exon II of MHC-DRB1 Gene Using PCR-RFLP Technique and Its Association with Growth Traits in Adani Goat

In the present study, blood samples were collected from 97 Adani goat from Bushehr province in order to identify the polymorphism in the exon II region of MHC-DRB1 gene (Major Histocompatibility Complex) and also, its association with growth traits (birth weight and 3 months weight). Genomic DNA was extracted from blood samples. A 279-bp fragment was amplified using polymerase chain reaction (PCR). Eventually, the PCR products were digested by RasI enzyme. The results showed that there were 4 types of alleles A, B, C and D in this locus with the frequencies of %51, %26.8, %13.4 and %8.8, respectively. Five genotypes including AA, AB, BB, AC and AD were identified with the frequency of %14.432, %28.866, %12.371, %26.80 and %17.525, respectively. The results indicated polymorphism and high heterozygosity in the population under study. Also, the number of effective alleles, Shannon index, expected and observed heterozygosity for this site was calculated at 2.794, 1.179, 0.642 and 0.732, respectively. Moreover, the chi-square (χ2) test showed that population was not in Hardy-Weinberg equilibrium. The ANOVA results showed that the effect of different genotypes on birth weight was significant (p<0.05), but it was not significant on 3 MW (p<0.05). Furthermore, other traits such as dam age, sex, season and birth type effects were not significant on the growth traits (p<0.05). The highest birth weight was found for heterozygous AC and AD genotypes (3.05 and 3.02 Kg, respectively), and the lowest birth weight was related to pure AA genotype (1.75 Kg). It seems that selecting AC and AD genotypes can be expected to increase birth weight in Adani goat. Also, we expect that this gene can act as a candidate gene for genetic improvement of some growth traits in goat breeding programs.