The first puppies conceived by in vitro fertilisation (IVF) have been born in the United States in what scientists described as a breakthrough in the study and possible eradication of genetic diseases in dogs and humans.
The development could also help efforts to protect endangered species of wild canids - dogs, wolves, foxes, jackals, coyotes and other dog-like species - which until now could not be bred in captivity with the help of IVF technology, scientists said.
Seven healthy puppies were born to a female beagle which was implanted with frozen IVF embryos created by fusing sperm and eggs from donor animals. They were the first successful IVF births in dogs.
Attempts at using IVF technology in dogs previously failed after more than 30 years of research. The latest study succeeded by adding magnesium salt to the semen to activate their ability to fertilise eggs, the scientists said.
“Since the 1970s, people have been trying to do this in a dog and have been unsuccessful,” said Alex Travis of Cornell University in Ithaca, New York, who led the research.
Being able to create IVF embryos in canines would enable researchers to experiment with gene-editing technology to study and even eradiate genetic diseases that affect dogs and humans, Dr Travis said
Inbreeding within domestic dogs has led to an increase in various inherited conditions within certain breeds. Golden retrievers are prone to developing lymphoma, a blood cancer, and Dalmations carry a gene that predisposes them to urinary stones.
“With a combination of gene-editing techniques and IVF we can potentially prevent genetic disease before it starts,” Dr Travis said. The study, published in the on-line journal Plos One, also points out that dogs and humans share more than 350 heritable disorders or traits, which is almost twice the number shared with other species of animal.
undefined
Being able to create IVF dogs in a laboratory setting would also allow scientists to experiment on creating genetically-modified dogs that would further the understanding of the genetic disorders shared by dogs and humans, the researchers said.
“There is great and growing interest in better utilising the domestic dog as a biomedical research model. Domestic dogs exhibit spontaneous occurrence of cancers, and as pets they are exposed to environmental factors common to humans,” researchers said.
The seven puppies were born last July to a surrogate beagle mother. They were part of three IVF cycles involving three beagle mothers and two fathers - a beagle and a cocker spaniel - which created 19 embryos.
The embryos were frozen before implantation to ensure that the surrogate mother's reproductive cycle was perfectly timed to accept the IVF embryos. Jennifer Nagashima, lead author of the study, said the scientists were surprised at how many live births they achieved.
Dr Nagashima, a conservation biologist, said the technology could help to preserve the gene pools of endangered species of canids by creating IVF embryos from the sperm and eggs of individuals that would not otherwise have been able to breed.
“Currently, when genetically valuable individuals die, we collect and freeze ovarian tissue and sperm. Yet these tissues and cells are useless if they cannot be used to produce offspring. Despite decades of attempts at IVF, no live births have previously been reported,” she said.
The Independent