Analysis reveals ‘ultrarapid’ gene evolution behind diversity of feather color in chickens

Researchers at the Texas A&M College of Veterinary Medicine and Biomedical Sciences have uncovered how chickens achieve such vast diversity in feather color and pattern. By studying more than 10,000 chicken genomes, the team identified that a gene known as MC1R behaves differently than previously assumed. Rather than relying on a single mutation to create a new trait, chickens use a process of rapid genetic recombination to reshuffle multiple mutations.

Traditionally, scientists believed that individual mutations were responsible for specific color traits. However, this study reveals that nine distinct mutations within the MC1R gene can be reshuffled into 18 different versions. This combinatorial process allows for significantly more variety than the simple accumulation of isolated changes. Dr. Leif Andersson describes this as a case where one plus one equals four, as recombination allows existing genetic changes to interact in new ways.

This study highlights how domestic breeding over the last 8,000 years has accelerated evolutionary change. Because breeders consistently selected for specific visual traits, they pushed the MC1R gene to evolve much faster than anticipated. This provided the research team with a high-resolution view of how genetic diversity is maintained and expanded across generations.

The implications of these findings extend beyond poultry science. While the data helps breeders preserve specific breed standards by clarifying the genetic basis of coloration, the mechanism itself may be a key factor in how biodiversity develops in other species. Future research will focus on how common this genetic reshuffling process is across the broader animal kingdom, potentially changing how we track the development of physical characteristics in various vertebrates.