Genome-Wide Association Studies in Japanese Quails of the F2 Resource Population Elucidate Molecular Markers and Candidate Genes for Body Weight Parameters

Molecular research for genetic variants underlying body weight (BW) provides crucial information for this important selected trait when developing productive poultry breeds, lines and crosses. We searched for molecular markers-single nucleotide polymorphisms (SNPs)-and candidate genes associated with this trait in 240 F₂ resource population Japanese quails (<i>Coturnix japonica</i>). This population was produced by crossing two breeds with contrasting growth phenotypes, i.e., Japanese (with lower growth) and Texas White (with higher growth). The birds were genotyped using the genotyping-by-sequencing method followed by a genome-wide association study (GWAS). Using 74,387 SNPs, GWAS resulted in 142 significant SNPs and 42 candidate genes associated with BW at the age of 1, 14, 28, 35, 42, 49 and 56 days. Hereby, 25 SNPs simultaneously associated with BW at more than one age were established that colocalized with nine prioritized candidate genes (PCGs), including <i>ITM2B</i>, <i>SLC35F3</i>, <i>ADAM33</i>, <i>UNC79</i>, <i>LEPR</i>, <i>RPP14</i>, <i>MVK</i>, <i>ASTN2</i>, and <i>ZBTB16</i>. Twelve PCGs were identified in the regions of two or more significant SNPs, including <i>MARCHF6</i>, <i>EGFR</i>, <i>ADGRL3</i>, <i>ADAM33</i>, <i>NPC2</i>, <i>LTBP2</i>, <i>ZC2HC1C</i>, <i>SATB2</i>, <i>ASTN2</i>, <i>ZBTB16</i>, <i>ADAR</i>, and <i>LGR6</i>. These SNPs and PCGs can serve as molecular genetic markers for the genomic selection of quails with desirable BW phenotypes to enhance growth rates and meat productivity.