In work expected to further efforts to preserve endangered
wildlife and enhance human health, scientists at Cornell University have
succeeded in joining canine egg and sperm, creating embryos, implanting them in
the uterus of a female carrier and seeing the gestation of those puppies-to-be
to birth.
The successful birth of seven healthy puppies ended about
two decades of failed efforts to make the commonly used infertility treatment
work on canines, whose reproductive biology differs from that of humans in a
wide range of particulars. In humans, physicians have made a science -- and a
booming business -- of stimulating egg growth, retrieving oocytes, introducing
egg and sperm, cultivating the resulting proto-embryos in laboratory medium and
transferring blastocysts to a woman's uterus.
But that multi-step process needed to be tweaked at many
points for success to be achieved in dogs. Success was achieved after 19
embryos were transferred into a healthy host female beagle and, after a period
of about 63 days, seven healthy pups were delivered by Caesarian section.
Report of the new research was published Wednesday in the
journal PLoS One.
Pierre Comizzoli, a research veterinarian at the
Smithsonian Institution's Conservation Biology Institute, said the work will
offer vital insights into the varied reproductive biologies of many animals.
There are 5,500 mammalian species, but scientists have only characterized in
detail the biologies of about 100 of them.
For conservation biologists intent on bringing a wide range
of endangered mammalian species back from the brink, the project should offer
new perspectives on techniques that work, said Comizzoli, who is not among the
authors but has been the Smithsonian's point person for joint work with Cornell
on the topic.
For human health too, the new work may bring discoveries.
Domestic dogs share with humans many diseases, including cancers, diabetes and
genetic disorders. So their response to experimental treatments can offer
useful insights into the likely outcomes of those treatments in humans.
At the cusp of a new era in which disease-related genes
might be edited out of a human's genome, dogs already have provided an
important model for experimentation. Because gene editing is done in the
laboratory, only with the success of IVF in canines can the animals become a
useful test bed for editing changes that might -- pending much ethical and
scientific debate -- be used in humans.
