Revolutionizing Turkey Production With Functional Genomics
By Rosalie Marion
September 8, 2004
A new method has been found for
analyzing turkey genes responsible for key proteins important to the hens'
fertility. Isolating such proteins could be a boon to U.S. producers, who must
artificially inseminate the huge flocks of hens that put about 5.6 billion
pounds of turkey on our tables annually.
The analytical method was refined by Agricultural Research Service (ARS) reproductive physiologist Kurt A.
Zuelke, who heads the ARS
and Germplasm Laboratory in Beltsville, Md. The method, called
SAGEfor Serial Analysis of Gene Expressionis a computerized form of
functional genomics and was originally used for human cancer research. Zuelke
adapted SAGE for the laboratory's livestock research.
The researchers used the SAGE technology to study genes in the turkey hen's
reproductive tract after artificial insemination. They measured gene expression
and genetic differences between cells in the presence of sperm, and the same
cells when no sperm were present. Expressed genes are those that are
"switched on" at a given time and, in turn, make proteins. Counting
the number of RNA transcripts, or copies, made by switched-on genes indicates
expression: Many transcripts signal high expression, while few transcripts
suggest low expression.
Zuelke's team was the first to report in scientific literature that the
presence or absence of sperm in a turkey hen's reproductive tract affects gene
expression. Learning which genes are switched on when sperm are present will
help researchers identify which proteins are produced under those special
circumstances. Those proteins could then potentially help prolong the life of
turkey sperm for artificial insemination.
Currently, the viability of turkey sperm outside of males, called
"toms," is only 10 hoursa relatively short period of time in
which to inseminate hens. Extending the sperm survival time to overnight would
greatly expand the range of options available for producers' artificial
more about this research in the September issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.