GENETIC MAPPING OF DISEASE RESISTANCE GENES IN CHICKEN

USDA-ARS Avian Disease and Oncology Laboratory 3606 E. Mount Hope Rd. East Lansing, MI 48823

Poultry is the third largest agricultural commodity and at 41% and growing, the main meat consumed in the United States. To meet the increasing demand of consumers, the industry has become more concentrated to maintain economic efficiency. This has the unfortunate consequence that the potential for disease outbreaks is higher. Already, the cost of disease is estimated to be 17%. With the reduced efficacy of existing vaccines and antibiotics, alternative control measures are needed. Genomics will play an important role in the improvement of poultry health. This field can provide the fundamental knowledge on the molecular and biochemical basis for disease resistance. To obtain this information, two approaches have been utilized. The first is the candidate gene approach where genes thought to be involved are tested. The second is the genome-wide QTL search where regions containing one or more genes associated with disease resistance are determined followed by the identification of positional candidate genes. In both approaches, a resource population segregating for disease-associated traits is required. Due to numerous genetic lines that exist in chickens, often these populations are derived from matings of divergently selected populations or characterized inbred lines. The identification of genes or QTL for relevant poultry diseases or general immune response will be discussed.