Identification of candidate genes affecting egg weight trait of Putian Black duck based on whole genome resequencing

Egg weight is a primary economic trait in poultry breeding. Putian Black duck, an excellent local laying duck breed in Fujian Province, includes two different strains, black feather strain and white feather strain. The white feather strain of Putian Black duck is also known as Putian White duck. Except for the different feather colors, these two strains differ in egg weight. In this study, whole-genome resequencing was conducted on Putian Black duck and Putian White duck to explore the differences in the genetic mechanism of egg weight. <i>LRP8, VLDLR,</i> and <i>LPL</i> were identified as key candidate genes affecting egg weight. Mass spectrometry was used to detect the SNPs of <i>LRP8, VLDLR,</i> and <i>LPL</i>. Result indicates that the SNPs of <i>LRP8, VLDLR,</i> and <i>LPL</i> in both populations exhibited moderate polymorphism, and Putian Black duck possessed higher genetic variation and potential selectivity. Association analysis indicated that in Putian Black duck, four SNPs in the <i>LRP8</i> gene were significantly associated with egg weight. These loci can be used as molecular markers for improving egg weight in Putian Black duck.