What has spots, 14 floppy ears, and represents a major advance in reproductive science? The world’s first litter of puppies born by in vitro fertilization (IVF). The Baker Institute welcomed the pups into the world on July 10, 2015, an advancement that will help preserve endangered canid species and open new means for discovery in human and canine genetic disease.
“Right now about five species of wild dogs and wolves are threatened with extinction, and managing fragmented populations of these animals is going to require more hands-on approaches,” says Travis. “We’re going to need technologies such as IVF to move genes around to maintain their genetic diversity and to improve the health of these species.”
An accomplishment of Dr. Alex Travis and his students and colleagues, the births are the first time IVF, in which ova and sperm are brought together to create embryos and then implanted in a female, has been successfully accomplished in dogs, a feat scientists had previously been unable to accomplish despite decades of effort. The puppies’ birth was a huge news item locally, nationally, and internationally, when it was announced in December.
Over a set of experiments, the team pinpointed the correct time after ovulation to collect mature eggs from female beagles, then combined them with either beagle or cocker spaniel sperm that had matured functionally in vitro. Once the resulting embryos had grown to the four-cell stage, they were frozen and stored until they could be transferred to a female hound when she was at the right stage of her cycle. The surrogate mother gave birth to seven healthy puppies (five beagles and two cocker spaniel-beagle mixes). Genetic testing indicated that the dog who carried the puppies to term was not the genetic mother, confirming the procedure had been completed successfully. The procedure is the culmination of many years of work in the Travis laboratory, as every step of harvesting oocytes and sperm, maturation, fertilization, freezing, storage, and transfer required testing and optimization.
All of the puppies were adopted by members of the scientific team. Travis himself adopted two beagles, who have kept the names Red and Green, names that hark back to the colors of the polish used on their nails to tell the newborn puppies apart.
Following up on the success of in vitro fertilization
In vitro fertilization opens doors to studying – and possibly preventing – genetic disorders in dogs and humans alike, and Travis and his team have been busy taking the research to this next step. He’s applying what he learned from the successful in vitro work to test his ideas about how to eliminate genetic diseases in dogs, combining in vitro fertilization techniques with gene repair techniques to change the genetic material that is passed down from parents to offspring.
“The genetic differences that make each breed of dog unique can also predispose those breeds to specific diseases,” says Travis, including certain forms of blindness, cancers, and others. “If scientists can identify what genes are responsible for a given condition, then coupled with new gene repair approaches, this technology gives us a way to actually fix that gene, and prevent illness rather than wait for the individual to get sick and then treat it.” Many of these diseases are directly similar to conditions in humans, providing benefit to both pets and people.
To test whether this will work, Dr. Travis’s lab is first attempting a proof-of-concept study with genes not related to disease, hoping to demonstrate that canine genes can be altered in very specific ways. He plans to report on this work in 2017.