A team of Cornell University and Smithsonian Institution researchers has, for the first time, successfully bred a litter of in vitro puppies. The complicated process could help save endangered species and prevent hereditary canine diseases. Science has never looked this cute.
Past attempts at canine [in vitro fertilization] failed because a female dog’s reproductive cycle differs from that of other mammals. Canine eggs retrieved at the same stage of cell maturation as other animals failed to fertilize. By applying the oocyte biology expertise of SCBI’s Nucharin Songsasen, a research biologist and co-author, the team found that if they left the egg in the oviduct one extra day, the eggs reached the stage where fertilization was most likely to occur. In addition, the female canine tract plays a role in preparing sperm for fertilization, so researchers had to simulate those conditions in the lab.
Another hurdle: dogs can only get pregnant once or twice a year, so the embryos have to be preserved until a potential mother reaches the right point in her ovulation cycle.
The seven puppies were born July 10. Two are cocker spaniel/beagle mixes, and the rest are beagles. Altogether, the puppies come from six parents, five males and the mother.
Study co-author Alexander Travis told The Associated Press that the team knew they were successful as soon as the puppies were born. "We each took a puppy and rubbed it with a little towel and when it started to squiggle and cry, we knew we had success…Their eyes were closed. They were just adorable, cute, with smooshed-in faces. We checked them to make sure they looked normal and were all breathing."
At seven weeks, they seem to be doing well:
Six puppies have been adopted, and one remains with the lab.
Danielle Wiener-Bronner is a news reporter.