They're not only adorable - they're a scientific
breakthrough. For the first time, a litter of puppies have been born using in
vitro fertilization, say Cornell University researchers.
A female dog fertilized with 19 embryos gave birth to seven
healthy puppies, according to a statement from Cornell's College of Veterinary
Medicine. Two puppies are from a beagle mother and a cocker spaniel father, and
the other five are the offspring of two pairs of beagle fathers and mothers.
"IVF was first done in people back in the mid
1970s," Alex Travis, associate professor of reproductive biology at the
Baker Institute for Animal Health, told CBS News. Yet until now, scientists
hadn't been able to perform it successfully in dogs, despite many years of
trying, he said.
For in vitro fertilization, a mature egg is fertilized in
the lab with a sperm, and an embryo is produced. The embryo is then transferred
into a host female at the right time in her reproductive cycle.
The first challenge for the researchers was to collect
mature eggs from the female oviduct (called Fallopian tubes in humans). The
researchers first tried to use eggs that were in the same stage of cell
maturation as other animals, but since dogs' reproductive cycles differ from
other mammals, those eggs failed to fertilize.
It's not as easy to perform in vitro fertilization in dogs
as it in in people, or cats, Penn Vet's Dr. Margaret Casal told CBS News.
"The cycle in the dog is so very different than in other species."
"Dogs only cycle twice a year so if your'e doing
experiments, there's not a lot of material," said Travis.
Through experimentation, the Cornell researchers discovered
that if they left the egg in the oviduct one more day, the eggs reached a stage
where fertilization was greatly improved.
Also, by adding magnesium to cell culture cultures, Travis
said they were able to better prepare the sperm for fertilization.
"We made those two changes, and now we achieve success
in fertilization rates at 80 to 90 percent," Travis explained in a
statement.
The final challenge for the researchers was freezing the
embryos. Freezing them allowed the researchers to wait until the right time in
the female dog's reproductive cycle and then insert them into the oviducts.
Travis said that part of the process was performed in May 2015.
In dogs, pregnancy is 63 days from ovulation -- a little
over 2 months, Travis said.
The Cornell team previously delivered Klondike, the first
puppy born from a frozen embryo in the Western Hemisphere, in 2013.
This first litter of IVF puppies, born July 10th, has broad
implications for wildlife conservation, Travis told CBS News.
"We can freeze and bank sperm, and use it for
artificial insemination." He said the technique could be used to conserve
the genetics of endangered species.
"The reason for doing things like this is that it will
lead to the preservation of species that are almost lost. Canid types - wolves,
foxes - certain sub-species. There are many different types. They may not be
facing extinction just yet but some are running into a crisis," said Penn
Vet's Casal, an associate professor of medical genetics, reproduction and
pediatrics for dogs and cats.
She said some types of wolves, for example, are very
genetically similar animal to animal - they have very similar immune systems.
"If some virus comes along that has mutated, it can
essentially wipe out the population. This gives the ability to freeze embryos
and perform IVF later to revive a species that may have been brought to
extinction," Casal said.
With new gene editing techniques, researchers may one day
be able to remove genetic diseases and traits in an embryo, too, ridding dogs
of heritable diseases.
"With a combination of gene editing techniques and
IVF, we can potentially prevent genetic disease before it starts," Travis
said.
Canines share more than 350 similar heritable disorders and
traits with humans, almost twice the number as any other species. So, dogs now
may offer a "powerful tool for understanding the genetic basis of
diseases," Travis said.
"Yes this is a very big deal. It's pretty spectacular
to get that to work," said Casal.
Jennifer Nagashima, a graduate student in Travis' lab and
the first to enroll in the Joint Graduate Training Program between the
Smithsonian Conservation Biology Institute and Cornell's Atkinson Center for a
Sustainable Future, is the paper's first author. The research was described in
a study published today in the scientific journal PLOS ONE.
Travis said the puppies have all gone to happy homes,
including his own. "I have two of them. We named them after colors and I
have Red and Green." The puppies turn five months old this week.
IVF puppy
These adorable pups are the first litter of puppies born by
in vitro fertilization. Cornell University researchers introduced them to the
world on Dec. 9, 2015. The seven puppies were conceived using an IVF technique
that took years to develop successfully for dogs, whose reproductive cycles are
much different than humans'.
Cuddle time
To create the IVF puppies, a female dog was fertilized with
19 embryos. She gave birth to seven healthy puppies, according to Cornell's
College of Veterinary Medicine. Two of the puppies are from a beagle mother and
a cocker spaniel father, and the other five are the offspring of two pairs of
beagle fathers and mothers.
Look-alikes
Two of the seven puppies born by in vitro fertilization.
Cornell researchers say the technique used to create this litter of pups could
also help conserve endangered species and eradicate heritable diseases in dogs.
Frolicking in the sun
These frisky puppies were born using in vitro
fertilization, the first successful IVF litter of dogs.
Chew toy time
Two of the IVF puppies play with their chew toys.
A little TLC
One of the IVF puppies gets some love from the team at
Cornell.
Out for a stroll
One of the seven healthy puppies born in the first litter
using in vitro fertilization.
Faces to love
The first litter of puppies born by in vitro fertilization.
Cornell University researchers say the successful use of IVF in animals could
eventually also help with conserving endangered species and eradicating
heritable diseases in dogs.
Sniffing around
Two of the first IVF puppies, born with the help of Cornell
University researchers after decades of failed efforts.
Puppy love
The first litter of puppies born by in vitro fertilization.
Researchers at Cornell's College of Veterinary Medicine transferred 19 embryos
to the mother dog, who went on to give birth to seven healthy puppies. Two
puppies are from a beagle mother and a cocker spaniel father, and the other
five are the offspring of two pairs of beagle fathers and mothers.
IVF puppies
It's not as easy to perform in vitro fertilization in dogs
as it in in people, or cats, Penn Vet's Dr. Margaret Casal told CBS News.
"The cycle in the dog is so very different than in other species."
VF puppies
Cornell University researchers introduced the first litter
of puppies born by in vitro fertilization on Dec. 9, 2015. Researchers had been
trying since the 1970s to develop an IVF process that worked in canines, whose
reproductive cycles are much different than humans'.
