Chicken Genome Leads to New Vaccine to Fight Poultry Disease
Researchers in Michigan, Delaware and Texas are using the chicken genome sequence to develop vaccines to combat Marek’s disease, a highly contagious, cancer-causing viral disease that costs the poultry industry $1 billion a year worldwide.
MAES scientist Jerry Dodgson and colleagues at MSU, the USDA Agricultural Research Service Avian Disease and Oncology Lab, the University of Delaware and Texas A&M University began by assembling the physical map of the chicken genome using DNA clones that describe all or nearly all of the genes in the chicken. The researchers then began to identify individual genes whose levels went up or down after infection by Marek’s disease virus (MDV). To do this, they used a “gene chip” with approximately 13,000 gene sequences (about half the chicken genes) to test levels of gene products before and after MDV infection, and in chicken lines that were highly susceptible versus lines that were more resistant.
In the field, MDV spreads from bird to bird via inhaled feather dander. Any infected tissue is a mixture of uninfected and infected cells that are closely intermingled, making it difficult to distinguish differences between them. Using a laser to microdissect a clump of infected cells from uninfected ones, the group discovered a suite of genes in the chicken genome that influence the course of viral infection. This new understanding of the interaction between the virus and the genes was used to develop new ways to identify genes in the chicken that are turned on or modified by MDV infection.
A new recombinant vaccine was developed by cloning one of the identified genes, called chicken MIP-1, into the vaccine strain of the virus. The protection this vaccine provides is comparable to that afforded by the best commercially available vaccines.
The chicken genome sequence developed during this project is now available to scientists working on MDV worldwide. The data generated by this project are also available on two Web sites, the U.S. Poultry Genome Project Web site at Michigan State and the U.D. Chick EST Database Web site at the University of Deleware, to provide other scientists instantaneous access to the data prior to publication.
The project was funded by the U.S. Department of Agriculture Cooperative State Research, Education and Extension Service through the Initiative for Future Agricultural and Food Systems program.
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