A new litter of puppies is always cause for celebration, but seven healthy beagle mixes born under the watchful eyes of Cornell University scientists represent a whole new world for canine breeding. They’re the first puppies born from embryos derived from in vitro fertilization. 

In this week’s PLOS ONE, researchers from Cornell University and the Smithsonian Conservation Biology Institute reported a successful birth of live puppies conceived from 19 IVF embryos. Delivered through caesarian section in July, two of the puppies were conceived with the help of sperm from a cocker spaniel father and eggs from a different beagle mother, and five were conceived by genetic material from different beagles. The dog who gave birth to them was a beagle. 

Scientists have been attempting to breed dogs through IVF for decades, in part because they make such good research models. Dogs exhibit 350 traits and disorders that scientists think are good models for human disease (about double that of most species). They get cancer, and because they live in our homes as pets, are exposed to similar environments as people. However, they have very different reproductive cycles—they only ovulate once or twice a year, and their oocytes, or egg cells, are dark colored and very immature, making them difficult to identify and harvest.  

IVF could also potentially be used as a way to conserve endangered species and rare breeds of dogs. In the future, it might help rid certain breeds of dogs of the heritable diseases they’re predisposed to—labradors are more likely to develop Addison’s disease, for instance. The ability to control dogs’ reproduction also makes them a much more attractive candidate for use in modeling diseases in the lab. 

Most of the now five-month-old puppies have been adopted. 

[h/t The Guardian]