For the First Time Dog was Born through the Method of Genetic Modification Combined with Cloning

Scientists have applied the gene-editing technique CRISPR-Cas9 and cloned it in dogs, producing puppies without disease-causing genes, and improving cognitive and physical abilities.

By combining gene editing with somatic cloning by nuclear transfer, Korean researchers have for the first time produced dogs with more stable and more evenly edited genes from the first generation.

This technique could limit or even eliminate genetic diseases in purebred dogs, allowing for the development of more targeted and precise treatments.

But the limits of this are still poorly understood and can pose ethical problems for animal rights defenders.

Nearly 36,000 years ago, humans began to domesticate wolves (Canis lupus), since most dog breeds today are descendants of wolves (with a few exceptions), including domestic dogs. Canis lupus Families).

Therefore, through the thousands of years of domestication of the wolf, its genome has been gradually modified to gradually adapt to human needs and preferences.

This evolution would have taken place through natural selection, or from human migration – domesticated dog breeds may have crossed and mixed across continents.

And today, humans seem to want to influence this genetic evolution more radically thanks to biotechnology. And researchers from the Korean company ToolGen have combined CRISPR-Cas9 technology and cloning for the first time to produce two healthy puppies.

This inexpensive, precise technology has inspired many companies around the world to test new dog breeds or "revive" the pets of wealthy clients.

Its advantage is to eliminate genes that cause disease or improve cognitive and physical abilities.

"The favorable traits resulting from gene editing can be passed on from generation to generation," said Liangxue Lai, a researcher at the Regenerative Biology Key Laboratory of the Guangzhou Institute of Biomedical and Health Sciences, China. systems and can breed a large number of genetically modified dogs, which can be marketed."

For somatic cloning by nuclear transfer, it has been used in dogs in Korea, to produce a black and white Afghan hound. Named Snuppy, the greyhound was born from the skin cells of the father's ear combined with the egg of a surrogate female.

Advantages of the two techniques combined

Korean researchers have successfully combined this cloning technique with CRISPR-Cas9 gene editing. That eliminates the need for scientists to cross-breed for the desired genes to be fully expressed.

The main advantage of the new method is its ability to eliminate pathological genetic mutations in purebred dogs. The lack of genetic diversity often leads to the more frequent occurrence of recessive phenotypic mutations.

Thus, ToolGen's technique can modify these genes without the risk of altering other traits and preserve the purity of the breed.

This technology can also contribute to the protection and conservation of biodiversity, by applying it to endangered species.

Because of the existence of the species, these animals are often forced to breed among close relatives. Their too-limited numbers or territories lead to inbreeding, causing the more frequent occurrence of genetic diseases, forming an additional threat to the survival of the species.

This technology has the potential to overcome and alleviate the problem, by eliminating disease-causing mutations. In their experiments, the researchers took skin cells that caused the DJ-1 gene mutation to block the expression of the protein it encodes.

This gene is particularly associated with various diseases, such as Parkinson's. Other genes have also been added, including one that expresses a green fluorescent protein to facilitate the tracking of successfully transfected cells.

For nuclear transfer, cells are placed near the egg from which the DNA has been previously removed. The cells and eggs were then fused by electrical pulses introduced into their medium, and the 68 resulting embryos were implanted into six surrogate females.

According to experts, this experiment gave birth to two puppies, who are now 22 months old and show no abnormalities. However, because the diseases caused by DJ-1 are age-related, dogs can develop diseases with age.

The researchers also stress that the animals will only be used for medical research. Furthermore, this type of testing remains the subject of much ethical debate.

The study was published in the journal BMC Biotechnology.