Robin Morgan and Joan Burnside of UD's Center for Agricultural Biotechnology, in association with the Delaware Biotechnology Institute, have received a $950,000 grant to study the genetic makeup of broiler chickens as part of a larger effort to produce disease-free, healthier birds.

The grant, from the U.S. Department of Agriculture (USDA) National Research Initiative, is intended to expand the development of an expressed sequence tag (EST) database of the chicken genome.

"Genomics offers the possibility of rapid gene discovery and opens up avenues for gene function studies on a previously unimaginable scale," Burnside, professor of animal and food sciences, says.

The further completion of this genome--which is similar in scope to the recently completed Human Genome Project--will help uncover many clues about chicken biology, including the mechanisms of growth and development, as well as immune competence and disease resistance.

According to Morgan, professor of animal and food sciences, one of the main priorities with poultry today is to make sure chickens are as disease resistant as possible. Chicken is a principal source of high-quality protein in the American diet.

"Infectious diseases have always threatened the industry," says Morgan, whose research is centered on Marek's disease--a disease that causes lymphomas in susceptible chickens within weeks after infection.

"In many cases, these diseases have been controlled with vaccinations, but we realize we may have reached the limit of what vaccines can do." she says. "Now we are looking for strategies that will enhance vaccines or provide alternative means of disease control.

"Specifically, we want to understand T-cell function in chickens because T-cells are so critical to immune function," Morgan says. Because the immune system in chickens is not fully developed until about two weeks after hatching, she says, "if we could hasten the immune response of chickens, we could probably grow healthier chickens.

"It's important for us to understand how these systems work, regardless of whether we want to make better vaccines, or whether we want to raise chickens that are more disease resistant. Genomics is a powerful tool to study immune competence in these birds."

According to Burnside, the EST database project had its genesis at UD in 1997 when she sequenced her constructed library of expressed chicken T-cells at a sequencing lab in the nearby Delaware Technology Park. The sequenced genes, which comprise one of two such chicken collections worldwide, were submitted to GenBank, a public database. To date, about 8,000 genes sequences have been obtained from Burnside's library of T-cell genes.

After the functioning genes are identified at the lab, they are automatically compared with every other gene that has ever been sequenced in any genome.

"Of the first 5,000 sequences from our library that were compared with existing genes in other species, about 40 percent are new genes," says Morgan. "We don't know what they are."

Burnside and Morgan compare the expressed genes from different situations. For example, they might compare the expressed genes from an uninfected bird with the genes of an infected bird, or the genes of a bird that is very susceptible to disease with the genes of a bird that is very resistant to disease.

"The strategy is to ask, 'Which genes are expressed in a particular cell?'" Morgan says. "Of course, we expect to find 'housekeeping' genes--those that encode the structural and general proteins that would be present in all living cells. But, we also expect to find other genes that are uniquely expressed in T-cells.

"In fact, many interesting chicken genes have been discovered in this manner," she says.

"As a result of the USDA award, we expect to obtain an additional 35,000 DNA sequences that represent genes expressed in chicken tissues," Burnside says.

"One of the important aspects of our work is that this information is being shared with scientists everywhere," she says, noting that the expressed chicken sequences are available via a web site at [http://www.chickest.udel.edu].

"We are trying to understand the immune system, to hasten immune development and to preserve the ability of the immune system to protect an organism as long as possible," Morgan says. "The expansion of the chicken genome through our USDA award represents a leap forward in allowing us to reach these goals."