A 24 BP Indel Prolactin Gene Polymorphism and Its Association with Some Reproductive Traits in Color Dual-Purpose VLV Hens in Southern Vietnam

Abstract

Polymorphism of the chicken prolactin gene at the 24 bp indel locus in the promoter region was studied, together with its association with the reproductive traits of color dual-purpose VLV hens. Egg production parameters were recorded as age at first egg (AFE; days), body weight at first egg (BWFE; gram/bird), mean egg weight (MEW; gram), and accumulated number of eggs (ANE) up to 38 weeks of age. DNA collected from the wing vein at 38 weeks of age was extracted from whole blood samples of 393 VLV chickens. The 24 bp indel/PRL target gene was amplified by PCR and the product was separated by electrophoresis on 2% agarose gel for genotyping. Polymorphism was observed at the 24 bp PRL/indel locus, showing two alleles I and D with frequencies 0.57 and 0.43, respectively and three genotypes (II, ID, and DD) with frequencies 18.3, 49.4, and 32.3%, respectively. Hens with the DD genotype had a significantly (P<0.05) higher ANE than hens with the ID or II genotypes. The regression equation, Y = 1.5437X + 58.386 (R 2 =0.0185) showed a positive correlation with the correlation coefficient (R) at 0.136. Polymorphism at the 24 bp PRL/indel with DD genotype and the correlation coefficient can be used for molecular-aided selection to improve egg production in native chickens, requiring more in-depth study.