WOODEN BREAST IS A BROILER BREAST MUSCLE DISORDER THAT RESULTS IN POOR MEAT QUALITY, RESULTING IN MILLIONS OF DOLLARS IN LOSSES FOR POULTRY PRODUCERS AND FARMERS EACH YEAR. SINCE THE FIRST TIME THIS CONDITION WAS REPORTED, THE FREQUENCY OF THE ISSUE HAS STEADILY INCREASED IN COMMERCIAL POULTRY OPERATIONS. THE GENERAL EXPLANATION HAS BEEN THAT SELECTION FOR RAPID GROWTH IS RESPONSIBLE FOR WOODEN BREAST, BUT THE GENETIC MECHANISMS FOR THIS CONDITION HAVE NOT BEEN CLEARLY IDENTIFIED. WHILE A GENETIC MECHANISM UNDERLYING THE CONDITION IS STRONGLY SUSPECTED, MUCH REMAINS TO BE DISCOVERED ABOUT THE GENETIC FACTORS AND MECHANISMS THAT EXPLAIN THE HIGH FREQUENCY OF THE CONDITION, AS WELL AS THE VARIABLE SEVERITY. IN THIS STUDY, WE WILL INVESTIGATE THREE LINES OF EVIDENCE TO UNDERSTAND THE GENETIC ORIGINS OF THIS CONDITION. THESE INVESTIGATIONS ARE BASED ON PRIOR STUDIES AND PRELIMINARY STUDIES LOOKING INTO THE MOLECULARMECHANISMS OF THE WOODEN BREAST.THE OVERARCHING HYPOTHESIS IS THAT THE SELECTION FOR LOW FEED CONVERSION RATIO AND THE HIGH METABOLIC RATE HAS ALTERED THE FUNDAMENTAL BIOLOGY OF BROILER CHICKEN, WHICH RESULTS IN ALTERED GENETIC PROCESSES THAT RESULT IN WOODEN BREAST. THE HIGH DEMANDS PLACED ON BROILERS TO GROW RAPIDLY IS EXPECTED TO HAVE SIGNIFICANT CELLULAR LEVEL IMPACTS, INCLUDING AN INCREASED DEMAND TO REGULATE RAPIDCELL PROLIFERATION.IN THIS STUDY, WE WILL DETERMINE WHAT THESE PROCESSES ARE AND THE PARENTAL ORIGINS OF THESE ISSUES. MODERN BROILERS ARE THE RESULT OF A FOUR-WAY CROSS (COMMONLY DENOTED AB X CD) AND IDENTIFYING WHETHER THE MALE OR THE FEMALE LINES ARE THE SOURCES OF CAUSATIVE GENETIC CHANGES WILL HELP ISOLATE THE CAUSES. IN AIM 1, WE WILL IDENTIFY DE NOVO (FROM SCRATCH) GENETIC CHANGES ARISING DUE TO FAST GROWTH. IN AIM 2, WE WILL IDENTIFY IF THE FAST-GROWING BREAST MUSCLE EXPERIENCE GREATER DNA REPAIR ERRORS, COMPARED TO OTHER TISSUE THAT GROW AT NORMAL SPEED. IN AIM 3, WE WILL DETERMINE IF MATERNAL OR PATERNAL ALLELES (COPIES OF THE SAME GENE) ARE EXPRESSED IN EXCESS OF WHAT MIGHT BE EXPECTED.WE EXPECT THAT UPON SUCCESSFUL COMPLETION OF THIS STUDY, WE WOULD HAVE NARROWED DOWN THE GENETIC MECHANISMS THAT ARE LIKELY CAUSING WOODEN BREAST. INFORMATION ABOUT GENETIC PROCESSES AND THE GENE AFFECTED CAN HELP INFORM HOW FUTURE BROILER BREEDING CAN PRODUCE BREEDS THAT DO NOT DEVELOP WOODEN BREAST. WE ANTICIPATE THAT THE COMPLETION OF THE STUDY WILL PROVIDE THE PRIMARY BREEDERS WITH ACTIONAL KNOWLEDGE FOR HOW WOODEN BREAST CAN BE AMELIORATED (OR ELIMINATED). FURTHERMORE, IF OUR RESULTS SUCCESSFULLY LINK THE GENETIC PROCESSES TO THE HIGH METABOLIC RATE - LOW FEED CONVERSION SELECTION, THE KNOWLEDGE WOULD PROVIDE A ROADMAP FOR IF AND HOW FUTURE BROILER BREEDING MAY KEEP THE PERFORMANCE WHILE REMOVING UNFAVORABLE HEALTH AND QUALITY TRAITS. SUCH KNOWLEDGE WOULD SAVE PRODUCERS MILLIONS OF DOLLARS ON AN ANNUAL BASIS, WHILE ALSO REDUCING FOOD WASTE (DUE TO POOR QUALITY) TO A GREAT EXTENT. TOGETHER THIS DATA WILL HELP IMPROVE THE SUSTAINABILITY OF BROILER PRODUCTION - A GLOBALLY IMPORTANT PROTEIN SOURCE.