Biotechnology, more commonly referred to as genetic engineering, is becoming a large-scale operation in the United States, and Utah is becoming more and more involved.
At Utah State University, several veterinary projects involving biotechnology are under way, including an effort to identify chemical patterns that are clues to a potentially disfiguring and fatal disease in sheep.Thomas Bunch is heading the effort to eliminate the spider lamb syndrome among Utah's Suffolk sheep population. The disease causes lambs to develop a twisted spine and angular limbs and generally leads to the animal's death within four to six months.
Bunch said the increased frequency of the disease over the past eight years has had a chilling effect on the Suffolk sheep industry in Utah. A study of pedigrees linked the problem to common ancestry, giving rise to speculation that the problem has a genetic cause. Further study indicated the disease is likely caused by a recessive gene that must be present in both the female and male sheep to be activated in their offspring.
Estimates are that 35 percent of the Suffolk breed carry the recessive gene.
Bunch said he hopes to use biotechnology to identify mutant gene combinations in DNA specimens, which would identify sheep with the recessive gene. To that end, he and his research team are working to develop what they call a gene probe using recombinant DNA technology. To develop the probe, researchers will be attacking a genetic coding system that has three billion bases and involves between 50,000 and 100,000 different genes and multiple regulatory elements.
Essentially the process will develop a genetic map of the Suffolk breed that can then be used to more easily locate mutations within the gene patterns - mutations that cause the genetic problems associated with the spider lamb syndrome. Once the genetic map is complete, the team will then look for certain sequences to unravel the genetic code. The goal is to find a sequence that appears common to the syndrome and then to develop a gene probe that will focus in on that sequence.
If the effort proves successful, sheep with the recessive gene could be identified with a simple blood test. Once identified, rams with the recessive gene can be culled from the breeding stock and eventually, through selective breeding, the recessive gene could eventually be eliminated.
Bunch said finding the key will take a lot of work. First, researchers will use a gel solution to isolate DNA samples. Researchers will use enzymes capable of recognizing legitimate base patterns to identify fragments not meeting that general order. The fragment will then be pulled out and put through a bacteria culture to make billions of copies. Other enzymes will be used to break down the fragments, looking for that one common pattern characteristic of the spider lamb syndrome.
"Hopefully we'll either find the mutant gene or at least the area next to it," Bunch said. "We'll then use that piece as a probe. It will be applied to DNA samples in blood and if the probe attacks, then we will know that that particular animal is a carrier."
Work is just beginning on the project and it will likely be five years before the probe is developed. Bunch said the key will be whether they can develop a test that is cheap enough to be attractive to sheep breeders. He said ranchers should be receptive because the test will provide an efficient and cost-effective method to identify carriers and, through selective breeding, eliminate the disease altogether in the future.
Bunch said this will help protect the value of breeding sheep by eliminating any question of susceptibility to the spider lamb syndrome. Also, the characteristics for which the sheep were selectively bred in the first place will be protected.