Genetic fine-mapping of body weight and size traits at 120 days of age in Lion-head geese.

Background: The Lion-head goose is one of the largest goose breeds all over the word. Body weight and body size traits at 120 days of age (i.e. the slaughter age) are economically important traits, which directly affect the profit of Lion-head goose industry. However, so far few studies have explored the genetic basis of these traits. This study for the first time integrated the single-SNP genome-wide association study (GWAS) and genetic fine-mapping based on whole-genome sequencing data to investigate the genetic architecture of body weight and 11 body size traits at 120 days of age in 504 lion-head geese.

Results: Single-SNP GWAS identified three major QTL regions located on Chr18: 2,436-6,745 kb (4,210 kb), Chr18: 9,756 - 10,076 kb (320 kb) and Chr25: 4,794-4,799 kb (5 kb), which were associated with body weight, semi-diving length, pelvic width, fossil bone length and chest depth. Genetic fine-mapping of these three QTL regions revealed 16 candidate genes and 68 important SNP-trait pairs. Out of these genes, MBTD1, CEP112, RAB11FIP4, APOH, and WIPI1 were associated with body weight and other body size traits. Among these SNP-trait pairs, we found a nonsynonymous mutation (c.C463A) in the MBTD1 influencing body weight and other two body size traits.

Conclusion: These findings will enhance our understanding of the genetic architecture of body weight and body size traits at 120 days of age, which support the application of molecular breeding on these economically important traits in Lion-head geese.