The development of an equine gene chip at Ohio State University promises to speed research into the genetic component of a variety of afflictions in horses.
The "gene chip", invented nearly a decade ago, allows researchers to scan thousands of genes at once to determine which are "expressed," meaning that they are directing the active production of proteins within the body.
"It used to be that you had to search for actively expressed genes one at a time, which was a very painstaking process that could literally take years," says Alicia Bertone, DVM, PhD, who developed the equine chip with researcher Weisong Gu. "This chip affords us a huge shortcut with great possibilities for research and diagnosis."
A small glass square about the size of a postage stamp, the gene chip is embedded with DNA probes that bind with complementary RNA extracted from specially prepared tissue samples. After RNA from the tissue binds to the chip's probes, a specialized computer scans the chip to identify the genes present in the sample and their level of expression.
"Chips help you quickly identify the genetic 'signature' of a disease," says Bertone. "For instance, we can take 100 horses with a particular disease, use the gene chip to scan their genes and identify what combinations of genes are expressed more than in horses without the disease. And we can do this in a matter of weeks or months instead of years."
The equine gene chip contains probes to identify 3,200 horse genes. When researchers began developing the chip two years ago, only about 200 genes were known.
"We've benefited greatly from human research," says Bertone. "The horse is genetically 90 percent similar to humans, so if a human gene associated with a particular trait or disease is identified, chances are the same gene has a similar function in horses." She adds that ongoing research will identify even more equine genes.
Gene chips for humans, mice, rats and a number of microorganisms have already been put to good use. The human gene chip was instrumental in isolating the genetic signature of particular forms of breast cancer, says Bertone, a breakthrough that allows those most at risk for the disease to undergo more intensive screening and take other extra precautions.
This article originally appeared in the April 2004 issue of EQUUS magazine.