THE US POULTRY INDUSTRY IS THE LARGEST POULTRY MEAT PRODUCER IN THE WORLD. HOWEVER, LIMITED GLOBAL FEED SUPPLY AND UNSTABLE COSTS REINFORCE THE URGENCY AND IMPORTANCE OF GENETIC IMPROVEMENT ON GROWTH AND FEED EFFICIENCY IN POULTRY. OUR CENTRAL HYPOTHESIS IS THAT CAUSATIVE VARIANTS IN REGULATORY ELEMENTS OF GENES ASSOCIATED WITH GROWTH AND NUTRIENT DIGESTION ARE THE MAJOR CONTRIBUTING MECHANISM FOR HIGHER GROWTH RATE AND FEED EFFICIENCY IN POULTRY. THIS PROJECT IS TO IDENTIFY CANDIDATE CAUSATIVE VARIANTS ASSOCIATED WITH GROWTH RATE AND NUTRIENT DIGEST EFFICIENCY BY COMPARING MODERN BROILERS WITH CONTROL COMMERCIAL BROILER LINE USING THE CUTTING-EDGE GENETIC AND GENOMIC ASSAYS. IF SUCCESSFUL, THE PROJECT WILL PROVIDE ANNOTATED GENES ASSOCIATED WITH GROWTH AND NUTRIENT DIGEST EFFICIENCY IN CHICKEN. MORE IMPORTANTLY, THE POTENTIAL CAUSATIVE VARIANTS IDENTIFIED FOR THEM WILL IMPROVE PRECISION GENOME SELECTION ON GROWTH AND FEED EFFICIENCY AND ENHANCE OUR BIOLOGICAL UNDERSTANDING OF KEY GENOME ELEMENTS THAT WILL TRANSLATE INTO SIGNIFICANT IMPROVEMENTS FOR US POULTRY BREEDERS AND PRODUCERS AND ULTIMATELY US CONSUMERS. FINALLY, MORE EFFICIENT ANIMALS WILL HAVE LESS OF AN ENVIRONMENTAL IMPACT, AN ISSUE OF GROWING URGENCY DUE TO CHANGES IN CLIMATE AND POPULATION GROWTH.