Follow
Test tube puppies have been bred for the first time ever, experts at Cornell University have revealed.
This incredible achievement, which was detailed in a scientific paper published on December 9 in the journal PLOS ONE, involves a group of 7 pups, born in July following in vitro fertilization.
The experiment was conducted by a team of experts led by Alex Travis, associate professor of reproductive biology at the Baker Institute for Animal Health, and Jennifer Nagashima, postdoctoral Fellow at the Smithsonian Conservation Biology Institute.
Initially, mature eggs which had been produced by the donors’ ovaries during ovulation were extracted from the Fallopian tubes.
The initial attempt at fertilization was unsuccessful because scientists hadn’t taken into account that dog’s menstrual cycles are quite dissimilar from those pertaining to other mammals.
In fact, precisely this had been the reason why prior experiments of this kind, which had been carried out in the last 4 decades, had also stopped in their tracks.
Researchers however didn’t allow themselves to get overly discouraged, and on the second try, the ovum was allowed to remain an extra day in the uterine tube, which proved to be a much more effective strategy.
Afterwards, experts had to account for the fact that during sexual reproduction, the genital tract assists in storing sperm, and makes it ready for fusing with the female egg cell.
This process had to be replicated within the confines of the laboratory, and it was rendered possible thanks to magnesium, which allowed sperm to travel much more quickly and to shed its cholesterol lining, that protects male dogs’ genetic material.
As a result of this reaction, DNA information could pass freely, and success rates climbed up to 90% when it came to facilitating impregnation.
Once researchers managed to create these zygotes (eggs that had been fertilized by sperm), they kept them in a Petri dish for around 48 hours. The following step was to freeze them, so as to be received by the surrogate mother.
Back in 2013, study author Alex Travis had been part of the team which was responsible for the birth of Klondike, a mix between a beagle and a Labrador retriever, which was the first dog bred in the Western Hemisphere, using cryopreservation, followed by artificial insemination.
Given this previous expertise, it was relatively easy for researchers to carry out this task of preparing the embryo, so as to be placed in the recipient’s womb at the ideal moment of the fertile window, which occurs semiannually, at best.
Eventually, seven puppies in perfectly good health were successfully delivered: 5 of them are pure beagles, while 2 others are bockers (a mix between a cocker spaniel dad and a beagle mom).
Scientists believe that this breakthrough will allow them to put an end to a wide variety of canine health issues (such as high lymphoma prevalence among golden retrievers), and might also assist in preventing the disappearance of dog species that are currently on the bring of extinction.
For example, as few as 3,000 specimens are left of the Cape Hunting Dog (Lycaon pictus), which is now categorized as endangered on the IUCN Red List of Threatened Species due to habitat loss and contagious diseases like canine distemper and rabies.
Moreover, given the fact that dogs suffer from around 350 genetically-related diseases which have also been encountered among humans, further insight into this field might also advance modern medicine, by making it possible to eradicate human afflictions.
Image Source: Scroll
