GENETIC HOMOLOGY ANALYSIS OF LRP8 GENE IN (ANAS PLATYRHYNCHOS) AND EVALUATING THE EFFECTS ON EGG QUALITY TRAITS FROM KHAIRPUR, SINDH, PAKISTAN

Abstract

The quality characteristics of eggs such as internal quality like yolk to albumen ratio are significant factors in affecting hatchability, embryo survival and post-hatch production performance in commercial waterfowl breeding. The exact genetic differences and molecular mechanisms controlling internal egg weight of breeding lines, however, are poorly characterized. In the present study, we sequenced a portion of the DNA of domestic breeding ducks (Anas platyrhynchos) that are classified into two extreme phenotypic groups: high (HP) and low (LP) yolk to albumen ratio. The functional annotation identified key candidate loci, such as the gene for low-density lipoprotein receptor related protein 8 (LRP8), a gene that has a central role in receptor-mediated endocytosis and lipoprotein homeostasis in vitellogenesis of the oocyte. In addition, a highly conserved region of the motif encoding "LENTCIE" was confirmed with Targeted Gene Cloning and Basic Local Alignment Search Tool (BLAST) sequence alignment, and was found to have a significant amount of sequence polymorphism and evidence of gene conversion in the binding regions affecting peptide specificity. The quality of the eggs is one of the factors influencing hatchability, embryo survival and production performance after hatching and is of importance in commercial waterfowl breeding, especially internal traits such as yolk-to-albumen ratio (YAR). This study combined high-density single-nucleotide polymorphisms (SNPs) and whole-genome resequencing (WGRS) to genetically map exact genomic variations and molecular pathways involved in the regulation of these internal egg production weights.