CALVES UNDERGO GENETIC EDITING TO PREVENT GROWTH OF HORNS.

The two calves that grace a muddy pen on the UC Davis campus will never grow horns typical of their breed. Instead, they’ll always sport soft hair on the parts of their heads where hard mounds normally emerge. The calves were designed in a petri dish at a Minnesota-based genetics lab, with the goal of making them easier to pack into pens and trucks without the nuisance of their horns taking up valuable space. Their offspring may also lack horns, and generations of hornless cows could follow, potentially saving the dairy and cattle industry millions of dollars, said Alison Van Eenennaam, a geneticist at UC Davis’ College of Agriculture and Environmental Sciences who worked with the Minnesota lab Recombinetics. This first-of-a-kind result of a process called genetic editing is a test run that’s expected to deeply impact the cattle and dairy industry and the entire food supply, Van Eenennaam said. It’s also part of a flurry of research looking at how to make cattle easier to maintain, transport and turned into food. The research has raised concerns among some farmers and animal-rights activists who warn of the health and ethical risks of consuming genetically modified food, but so far, that hasn’t stopped the research drive. At UC Davis, animal geneticist Pablo Juan Ross has been trying to perfect a technique developed a decade ago but now gaining more acceptance to design cattle that produce only male offspring.“Males grow faster than females, and in beef production they are more desirable,” Ross said. Another project uses stem cells to produce a clone animal, Ross said. Genetic editing could also help design cows that are less prone to pneumonia, which would reduce their need for antibiotics.Van Eenennaam is keen on using word processing as an analogy to describe the differences between genetic editing and engineering. She likens genetic editing to changing the spelling of a word within a document and genetic engineering to pasting in a word from a completely different document.“You’re not bringing in something foreign ... like introducing a protein from a tomato into a fish, which is what is associated in genetic engineering,” she said. The two dairy calves had a precise section of DNA responsible for horn growth was knocked out and replaced with a precise section from a cow that does not produce that trait. Many cattle varieties do not grow horns, including Angus cattle. With dairy cattle – both male and female – horns are a given, and the animals are dehorned soon after they’re born.Once the cows are sexually mature, Van Eenennaam will collect semen from the bulls to inseminate horned cows – the route by which most cows are impregnated in the cattle and dairy industry. The plan is to track the calves’ growth and development and see whether the two faithfully transmit the hornless trait to their offspring.“The odds are 100 percent if Mendelian genetics holds true,” she said.She added that it’s not clear whether other, unexpected effects of editing will appear. If successful, it will allow the industry to bypass decades of breeding for polled, or hornless, cows. At the University of Missouri, researchers focus on genetically modifying pigs to remove genetic traits for maladies such as retinitis pigmentosa, hemophilia and cystic fibrosis, said Randall Prather, an animal geneticist at the school. Story credit; http://www.sacbee.com/news/local/health-and-medicine/article50822850.html