Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/3/2007
Publication Date: 1/12/2008
Citation: Zhang, H., Heidari, M., Dunn, J.R., Yu, Y., Song, J. 2008. Genetic bases for Marek's disease resistance. Plant and Animal Genome Conference Proceedings. p. 96.
Technical Abstract: Marek's disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by MD virus (MDV). Therefore, the control of MD is of particular concern to the poultry industry. The poultry industry has been heavily relying on biosecurity and vaccination to control the spread and occurrence of MD. Genetic resistance to MD is recognized as an essential alternative strategy to augment current control scheme. Chickens resistant to MD are those that do not develop characteristic symptoms upon exposure to MDV. Study of genetic resistance to MD started in the early 1930’s. Since then, in addition to selection for resistant lines of chickens, the studies encompassed identification and characterization of MHC genes, non-MHC genes, and QTLs, which underlie the bases for resistance to MD. Reported studies provide compelling evidence that MHC plays an important role in resistance to MD. Under similar background and challenging conditions, chickens homozygous for B*21 haplotype reportedly are of the strongest resistance, and B*2 are of moderately resistance to MD among the B haplotypes. We have recently conducted a series of MD trials using chickens from four different lines that are either homozygous for B*21 or B*2. Both lines 0 and EV21 are B*21/B*21 homozygous and both lines 63 and 72 are B*2/B*2 homozygous. Under the same condition, when chickens were inoculated with a partially attenuated strain of vv+ MDV, 100%, 96%, 0%, and 100% MD incidences were observed in chickens from the four lines, respectively. These data suggest that non-MHC genes play a large role in genetic resistance to MD. These data together with reported studies indicate that interactions between MHC haplotypes and non-MHC genes, in addition to other high order interactions among genes, may also constitute an essential part of the bases of genetic resistance to MD. The influence of TVB genotypes and presence or absence of complete endogenous virus on MD susceptibility will also be discussed.