Genome-Wide Association Study of Body Weight and Body Size Traits in Wenshang Barred Chickens at the Late Rearing Stage

Abstract

Simple Summary Body weight and body size traits are critical indicators in poultry production, as they directly reflect skeletal development and muscle growth. However, indigenous chicken breeds typically exhibit slow growth during the late rearing period, the phase prior to marketing or the onset of lay, which substantially increases production costs. The genetic regulatory mechanisms of these traits remain poorly understood, limiting the effectiveness of targeted breeding programs for high-quality indigenous chicken breeds. Given that the growth traits during this stage are closely associated with slaughter and laying performance, improving them could enhance both production efficiency and economic returns. In this study, we conducted a genome-wide association study using 925 healthy 16-week-old Wenshang Barred chickens of both sexes to identify genetic markers and candidate genes associated with body weight and body size traits. Heritability estimates for these traits ranged from 0.18 to 0.48. The study revealed 4080 genome-wide significant single-nucleotide polymorphisms, 89 candidate genes, three important candidate regions, and four candidate pathways. Collectively, these findings provide a comprehensive genetic characterization of body weight and body size traits in Wenshang Barred chickens during the late rearing stage and may provide a basis for further evaluation of genetic markers in indigenous chicken breeding.