Submitted to: Stadler Genetics Symposium
Publication Type: Book / Chapter
Publication Acceptance Date: 3/31/2008
Publication Date: 3/31/2008
Citation: Cheng, H.H. 2008. Integrating genomics to understand the Marek's disease virus-chicken host-pathogen interaction. In: Gustafson, P., Stacey, G., Taylor, J., editors. Genomics of Disease. Stadler Genetics Symposium. New York, NY: Springer. p. 115-126.
Technical Abstract: Poultry is the third largest agricultural commodity and the primary meat consumed in the U.S. According to the USDA Agricultural Statistics (www.nass.usda.gov), in 2004 (latest year with complete information), the U.S. produced 45.8 billion pounds of chicken meat, 7.3 billion pounds of turkey meat, and 87.5 billion eggs for combined sales totaling $28.9 billion (up 24% from 2003!), and the industry is the largest producer and exporter of poultry meat in the world. Primarily due to advanced breeding programs, tremendous progress in production traits has been made to meet the growing demands of consumers. Several major issues confront the poultry industry today. Infectious diseases are certainly at or near the top of the list. Avian influenza, exotic Newcastle’s disease, Salmonella are just a few pathogens well known to the public that harm the poultry industry through loss of birds, reduced public confidence, and lost market accessibility via trade restrictions. Disease outbreaks or the potential for them to occur are enhanced by more concentrated chicken rearing and reduced genetic diversity from industry consolidation. Changes in animal husbandry (e.g., “all in, all out” rearing), new vaccines, etc. have helped to alleviate some of the problems, however, improved or alternative control measures are still needed in the near future to address current diseases and impede emerging threats. The field of genomics offers one of the more exciting avenues for solving many of these issues. While still in its formative years, by identifying quantitative trait loci (QTL) and genes that control heritable traits of agricultural importance, it is possible to select for birds with superior agricultural traits via marker-assisted selection (MAS).Other positive attributes commonly cited for MAS include greater speed and accuracy compared to traditional breeding. Furthermore for infectious diseases, MAS would eliminate the exposure risk to elite flocks associated with handling a hazardous pathogen. The recent release of the chicken genome sequence and funded improvements to finish the assembly only increase the power of this discipline. The ultimate goal is to address the long-standing question of how genetic variation explains the observed phenotypic variation. In this review, I briefly describe Marek’s disease (MD), the most serious chronic disease problem facing the poultry industry, and a very interesting model for cancer, vaccines, viral evolution, and host-pathogen interactions. Then I discuss how we are using genomic and functional genomic approaches to identify genes and pathways that confer resistance to MD. Given that most labs have limited finances and resources, this integrated genomics strategy may be appealing to others. Further, the impact of the chicken genome sequence has had on our approach is also described.