Chinese scientists have edited the genome of a puppy foetus while it is still an embryo inside the mother's womb, to create a breed of "super puppies". It is the first time that such a technique has been used on a mammal without the use of a surrogate mother to host the egg.
The scientists, led by Liangxue Lai of the Guangzhou Institutes of Biomedicine and Health, removed a myostatin gene in a pair of beagle embryos. Myostatin limits the muscle protein they can build, and as a result of removal, the dogs now have twice the normal amount of muscle.
Reported in the Journal of Molecular Biology, the study says that the successful research, rather than selling the dogs as pets, will allow scientists to tweak the DNA of canines so that they can contract diseases such as Parkinson's, which will allow experts to better understand how such inflictions operate. "We plan to make dog models for human genetic disease," wrote Lai.
Beagles were used in the experiment as the breed is often used for medical research due to their genetic similarity to humans. This is the first time that scientists have been able to edit the genome without the use of a surrogate dog because the embryo will die almost immediately when it is removed from the mother.
"That forced us to look for an alternative way to bypass the use of a surrogate [host]," Zou Qingjian, who was part of the research and of the Chinese Academy of Sciences' Guangzhou Institute of Biomedicine and Health, told the South China Morning Post.
"We tried to use traditional methods to grow the embryo in another womb nearly one hundred times but they all failed. We realised there must be something wrong, and that we should return the embryo to the biological mother. A major challenge of this technology is speed. We must finish editing the genome in less than half an hour, which requires [a lot of] practice."
Zou added: "Removing the muscle-blocking gene is only the first step. Beagles are very smart, with a cardiovascular system very similar to that of a human's. We will soon use them to study a wide range of important diseases including Parkinson's, Alzheimer's and heart diseases."