LOGAN – Utah State University was recently involved in an international project that sequenced the DNA of the entire sheep genome. The project lasted several years and included over 100 researchers across the world.
DNA is made up of chains of four different bases abbreviated as A’s, C’s, G’s, and T’s. The order and amount of those bases determine every living organism. Sequencing a genome involves figuring out the order of the bases and recording them.
“The order determines whether it’s bacteria or a strawberry or a pine tree or a human or a sheep,” said USU Executive Vice President and Provost Noelle Cockett, who was responsible for obtaining funding for the project and verifying the results. “But then within that species it determines how big that strawberry is or what color that strawberry is.”
In the DNA strands of each mammal cell, there are about 3 billion A’s, G’s, C’s and T’s in a specific order. Those three billion parts had to be sequenced in pieces and put together like a puzzle.
“We got small chunks of like 25 to 75 bases long, but it was chopped up all across the 3 billion and we had to overlap those so that they made a continuous sequence,” Cockett said. “We had all these little pieces and we had to line them up so it was the DNA sequence of a sheep.”
Cockett said this is the first time the genome of a particular species other than humans has been completely sequenced. She said that when the human genome was sequenced it cost billions of dollars, but because of improved technology, methods and computing power, this project cost about $1 million.
Cockett said the sequenced genome lays a foundation for comparisons across species and it will be a great tool to speed up discovery with different traits among sheep.
If there is a sheep that has an unusual production trait such as superior wool or additional horns, the sequenced sheep genome can be used as a master copy to determine which genes cause the differences.
“Now I can just go straight to that location, I can look at the genome sequence of the sheep that we’ve published and I can say ‘Well there’s this gene, that gene, this control element. What makes the most sense for being the regulator of these horns?’” Cockett said. “So it improves the efficiency of genetic discoveries in sheep.”
Cockett said that this will be an incredible boost for other people working with sheep.
“I mean it’s just, we’ve had all sorts of discoveries just within the last year where people had a region of interest that they had been wondering what had been happening with that,” she said. “Now, within a very, very short time, they have been able to discover what that difference is.”