Growth Hormone Gene Polymorphism in Pekin Ducks Reared in Turkey

Advances in molecular genetics have led to the identification of genes or markers that affect many morphological and physiological characteristics of farm animals. The molecular basis of these traits is revealed by functional genomic methods and provides opportunities to develop genetic improvement programs in farm animals through marker assisted selection (MAS). Several candidate genes are being studied with the aim of increasing various yield and reproductive performances in animals through MAS. One of these candidate genes is the growth hormone gene. The main purpose of this study was to investigate polymorphisms in the 2nd, 3rd and 4th introns of the growth hormone gene in Pekin ducks. For this purpose, blood samples taken from a total of 117 adult Pekin ducks of both sexes (79 males and 38 females) raised in Bursa Uludag University Faculty of Agriculture Agricultural Application and Research Farm were used as material. Genetic polymorphism in the 2nd, 3rd and 4th introns of the growth hormone gene was investigated using the BsmF1 restriction enzyme in the PCR-RFLP method with three primer pairs. Samples were carried out in 2% agarose gel electrophoresis to separate the DNA fragments obtained after the digestion. As a result of the researches, polymorphism was determined only in the fragment amplified from the 2nd intron region. As a result of the digestion of the amplified fragment from the 2nd intron region with BsmF1 restriction enzyme, three genotypes, namely TT (765 bp), CT (765, 593 and 172 bp) and CC (593 and 172 bp) were determined in this region and the frequencies of the T and C alleles were calculated as 0.75 and 0.25, respectively. Since the difference between the values observed in the 2nd intron region of the growth hormone gene and the expected values in the studied population was not statistically significant (P>0.05), it was understood that the population in studied was in Hardy-Weinberg equilibrium. No genetic variation was observed in the 3rd and 4th introns. PCR products belonging to the 442 bp and 1378 bp regions of the 3rd and 4th introns of the growth hormone gene, respectively, were also treated with BsmF1 restriction enzyme, but the cleavage region of this enzyme was not found, so there was only one genotype was obtained in the 3rd and 4th introns of the studied population. Therefore, it was understood that these two regions are monomorphic in terms of BsmF1 locus. The genotypic variation shown in the 2nd intron region of the growth hormone gene in this and previous studies also reveals the need for further studies on the relationships between this region and various yields.