|Liu, Hsiao Ching|
Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/4/2001
Publication Date: N/A
Interpretive Summary: Marek's disease (MD), a virus-induced cancer-like disease of chickens, is considered a major disease problem to the poultry industry. Vaccination has helped to contain the MD incidence, but with the emergence of more virulent viral strains, there is great need to develop alternative control strategies. The objective of this research was to integrate two methodologies to see if the combination enhanced the ability to identify chicken genes that may confer genetic resistance. We identified gene expression variation that was specific for MD resistant chickens for many genes. The information obtained from this research is of great interest to the poultry industry as DNA markers for these genes can be used to select chickens with superior MD resistance. It is also of use to the scientific community as it demonstrates how various techniques can be combined to complement existing approaches.
Technical Abstract: Marker-assisted selection to enhance genetic resistance to Marek's disease (MD) in chickens is an attractive alternative to augment vaccinal control. Our earlier studies indicate that there are many quantitative trait loci (QTL) containing one or more genes of significant effect that confer genetic resistance to MD. Unfortunately, it is difficult to resolve these QTL down to a size necessary to generate tightly linked markers to select the appropriate alleles or identify the causative gene. One possible solution is to identify positional candidate genes by virtue of gene expression differences between MD resistant and susceptible chickens using DNA microarrays followed by genetic mapping of the differentially-expressed genes. In this preliminary study, we show that DNA microarrays containing about 1,200 genes/ESTs are able to detect differences in gene expression between the inbred ADOL lines 6 (MD resistant) and 7 (MD susceptible) in both uninfected and MDV- infected peripheral blood lymphocytes. The microarray data is consistent with previous literature on the action of immune-related genes suggesting that this technology is useful for developing testable hypotheses. Integration of the microarrays with genetic mapping data was achieved with a sample of fourteen genes that showed differential expression. Eleven of these genes had mapped human orthologs. Six genes were located on the chicken linkage map predicted by the human-chicken comparative map, while two other genes defined a new conserved syntenic group. The potential and future challenges of this approach are discussed.