Genome-wide association study for behavior, type traits, and muscular development in Charolais beef cattle

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Livestock Breeding

Background:

• Understanding the genetic basis of traits like behavior, type, and muscular development is crucial for beef cattle breeding.
• Genome-wide association studies (GWAS) are powerful tools for identifying candidate genes and understanding trait architecture.

Purpose of the Study:

• To conduct a GWAS for 3 behavior traits, 12 type traits, and muscular development in Charolais cattle.
• To identify genetic regions associated with these economically important traits.

Main Methods:

• Phenotypic data for behavior (aggressiveness, maternal care) and type traits (udder, feet, legs, locomotion) were collected.
• Genotyping data for 44,930 single nucleotide polymorphisms (SNP) from 3,274 Charolais cows were analyzed using GWAS.
• Significance thresholds were determined using a false discovery rate (FDR) < 0.05 for significant and 0.05–0.20 for suggestive associations.

Main Results:

• Four significant and 12 suggestive genomic regions were identified for traits including aggressiveness, maternal care, and various type traits.
• No major-effect SNP were found for behavior and type traits, indicating polygenic inheritance.
• A significant association with muscular development was found on chromosome 2, including the myostatin gene, with pleiotropic effects on udder and leg traits.

Conclusions:

• Behavior and type traits in Charolais cattle are likely influenced by many genes with small effects.
• The myostatin gene region is a key genetic factor for muscular development and has pleiotropic effects on other traits.
• GWAS provides valuable insights for genetic selection in beef cattle breeding programs.