Page 35 - Breeding Edge ebook

young human recipient of the cells would not reject them. The altered T-cells were then used to replace
a childhood leukemia patient’s own T-cells. The child gained full remission from leukemia.

Most of the gene editing successes have worked within the animal’s own genes, not injected ones
from other species, and are intended to reduce suffering, infections, and injuries.

For example, Acceligen is working with Van Eenennaam and scientists at UC-Davis to gain government
approval for its genetic amendment for polled cattle, which means that they don’t grow horns. A few
breeds are naturally hornless. Cattle with horns can injure others in the herd or people handling the
cattle. Meanwhile, dehorning adds to management chores for ranchers and means pain and blood loss
for calves.

Tad Sonstegard, Acceligen’s chief scientific officer, explained that isolating precise gene amendments
for the polled trait can allow ranchers to make that sole change directly to a herd. Making a single
targeted change can relieve the breeder from needing several generations to rebuild the genetic profile of
the herd.

Australians found that while European-origin cattle (including American breeds) assimilate Acceligen’s
polled trait, hot-climate cattle such as Brahman and Bos indicus (zebu) cattle raised in northern
Australia, do not. So Australian researchers did their own gene editing to select the polled trait for their
breeds, allowing the rancher to breed cattle with double-dominant genes for the “true-polled” inherited
hornless trait.

Another pain-reduction application of gene editing on tap in the swine sector is eliminating the need for
surgical castration to produce favorable tasting pork. For swine, castration is done to avoid so-called
boar taint, an unpleasant odor and taste in pork.

Recombinetics and DNA Genetics, a swine genetics supplier, have joined ranks to perfect a breeding
technology that results in male piglets remaining in a pre-puberty state – thus, naturally castrated, in
effect. Besides avoiding pain for piglets, GE castration would save labor and avoid risk of infection from
the surgical procedure.

“We are trying to make male and female parents both sterile, and they will
only be able to reproduce if someone administers spawning hormones to
them. So, then the resulting offspring will all be sterile,” Auburn University
geneticist Rex Dunham said. He notes that some fish breeds are naturally that
way, and won’t breed unless certain hormones are present at high enough
levels in the water.

In the aquaculture sector, meanwhile, Dunham has inactivated three genes in Rex Dunham, Auburn
catfish cell nuclei, which direct release of reproductive hormones that allow University
the fish to breed.

“The primary purpose,” he explains, “is to have complete reproductive
control over transgenic or other types of gene-edited fish. So, we could
almost entirely eliminate any possibility of environmental impact, and
completely prevent them from interbreeding (with other catfish).”

www.Agri-Pulse.com 33