Scientists in South Korea have successfully cloned two beagle puppies from genetically altered cells. Announcing their achievement in the journal BMC Biotechnology, the researchers describe how they used CRISPR gene-editing technology to manipulate a particular trait in the pair of pooches, and reveal that no abnormal characteristics were observed in either dog at 14 months of age.
Specifically, the study authors sought to create dogs that lacked a protein called DJ-1, which is associated with neurodegenerative disorders such as Parkinson’s and Alzheimer’s diseases. To do so, they first extracted cells called fibroblasts from a beagle fetus and removed the gene responsible for DJ-1 using CRISPR.
These altered fibroblasts were then fused with beagle egg cells that had had their nuclei removed, before being implanted into surrogate mothers. In total, 68 embryos were transferred into six separate female dogs, one of which became pregnant before giving birth to the two clones.
The creation of embryos by fusing egg cells with body cells is known as somatic cell nuclear transfer (SCNT) and was first used in dogs back in 2005, when an Afghan hound called Snuppy became the first canine to enter the world via this method. According to the researchers, the technique has since “been used not only for pet cloning but also for propagating elite working dogs, including sniffing dogs and rescue dogs.”
“This technology has also been used to preserve rare canine breeds and endangered canid species such as wolves,” they explain.
However, by performing SCNT using gene-edited cells, the study authors have shown for the first time that it is possible to create cloned dogs with targeted traits. In this case, DJ-1 expression was “either downregulated or completely repressed” in each of the resultant hounds.
While the four-legged results of this particular experiment are for research purposes only, the authors state that their approach could have a number of useful applications in the future, such as “correcting pathogenic mutations in purebred dogs.”
“Because breeding programs with a limited number of founder dogs are strictly selective, purebred dogs have a greater risk of genetic disorders than any other species,” they write. The implication, therefore, is that this new technique may be used to correct these specific flaws without affecting any other traits.
However, because DJ-1 plays a role in many age-related illnesses, the full impact of this genetic deletion on the dogs’ health may not become apparent until they are older. For now, both are described as “healthy”, but the researchers say they are “continuously monitoring” the dogs and will provide more details about their long-term wellbeing in future studies.