Scientists in China report that they have been able to use gene editing technology for the first time to breed special dogs. They created beagles with double the amount of muscle mass by removing the gene responsible for the production of myostatin protein. This protein inhibits the growth and differentiation of muscle tissue.
During the work, the team used CRISPR / Cas9 genetic editing technology, with the help of which pigs were also recently bred, whose organs are more suitable for transplantation to humans.
In the course of the work, the researchers injected chemicals and the Cas9 molecule into the embryos of 65 dogs in order to damage or destroy both copies of the gene responsible for the production of myostatin so that the protein that inhibits muscle growth is not produced in the bodies of the beagles. Later, 27 puppies were born, but only two of them (male and female) had both copies of the "muscle gene" disabled.
“These dogs, named Hercules and Tiangou, or“heavenly dog,”have more muscles than regular beagles. We believe that their strength and speed will also be better than those of their congeners,”Liangxue Lai comments on the work. "They will be better suited for hunting and police work."
Note that the gene editing in Hercules was incomplete - a small percentage of the dog's muscle cells still generate myostatin. However, Tianguou lacks myostatin completely, and her muscles from birth were larger than those of her fellows.
Similar violations, by the way, are found in nature - in dogs of the Whippet breed. But the benefits of this work may not only be for dog breeders.
American doctors are also trying to block myostatin production with experimental gene therapy in an effort to slow the loss of muscle mass in boys suffering from Duchenne muscular dystrophy.
Similar disorders sometimes occur in Whippet dogs due to mutation.
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Lai and his colleagues note that in the near future they plan to create dogs with other changes in DNA, including those that will mimic human diseases such as Parkinson's disease and muscular dystrophy. These animals can then be used to test treatments for these diseases.
“The goal of our study is to explore an approach to creating new animal models for biomedical research,” says Lai. "Dogs are very similar to humans in terms of metabolism, physiological and anatomical characteristics."
Lai noted that his group has no plans to breed the muscular beagles as pets. However, he does not rule out that other research teams may commercialize genetically modified dogs, changing their size, increasing intelligence or eliminating genetic diseases.
For example, in September, representatives from the Beijing Institute of Genomics announced that they were beginning to sell miniature pigs created with gene editing for $ 1,600 each.
Genetically modified beagles currently live at the Central Pharmaceutical Research Institute in Guangzhou, where scientists say there are more than 2,000 beagles used in biomedical research.
We add that it is not the first time that Chinese scientists have changed animals using CRISPR technology. They have already used it to create genetically modified goats, rabbits, rats and monkeys. They also used the genetic editing technique to change the genome of human embryos. Then scientists tried to change the gene responsible for the development of β-thalassemia.
An article published by the Journal of Molecular Cell Biology tells more about the new work of Chinese scientists.
