For example, game fowl are a group of breeds selected specifically for cockfighting, and fighting cocks possess congenital aggression towards all males of the same species. There are hundreds of phenotypically distinguishable domestic chicken breeds or lines worldwide, providing a unique opportunity to trace the history of domesticated poultry and define the signatures of selection resulting from both domestication and the natural environment. This has resulted in marked genetic diversity in a number of traits, leading to highly specialized chicken lines with unique traits, such as cockfighting fowls, bantams, meat and egg producing chickens. Since the domestication of the red jungle fowl ( Gallus gallus) (approximately 8000 to 5400 BC) in Asia, domestic chickens ( Gallus Gallus domesticus) have been subject to the combined effects of natural and artificial selection. Several genes were identified as candidates for chicken economic traits and other phenotypic traits. The work provides crucial insights into the distinct evolutionary scenarios occurring under artificial selection for agricultural production and under natural selection for success at high altitudes in chicken.
By comparing the genomes of the Tibetan and lowland fowls, we identified genes associated with high-altitude adaptation in Tibetan chickens were mainly involved in energy metabolism, body size maintenance and available food sources.
Chicken age progression skin#
We further identified strong signatures of selection affecting genomic regions that harbor genes underlying economic traits (typically related to feathers, skin color, growth, reproduction and aggressiveness) and local adaptation (to high altitude). We found an evidence of admixture between Tibetan chickens and other domestic population. Genome-wide analysis indicated that sex chromosomes have less genetic diversity and are under stronger selection than autosomes during domestication and local adaptation. Here, we provide a population genome landscape of genetic variations in 86 domestic chickens representing 10 phenotypically diverse breeds.
There are many local chicken breeds in China. There are hundreds of phenotypically distinguishable domestic chicken breeds or lines with highly specialized traits worldwide, which provide a unique opportunity to illustrate how selection shapes patterns of genetic variation.
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