The super-strong beagles, named Hercules and Tiangou, are the world's first genetically-engineered dogs.

By deleting a gene called myostatin, the researchers were able to produce dogs that had more muscle to improve their running ability.

A similar mutation occurs naturally in some whippets, leaving them with an unusually muscular body.

Of the 65 embryos the researchers edited, 27 puppies were born, but only two had the disruption to the myostatin gene.

Now the team at the Guangzhou Institutes of Biomedicine and Health wants to experiment with creating dogs with other DNA mutations, including ones that mimic human diseases like Parkinson's and muscular dystrophy.

Lead researcher Liangxue Lai told the MIT Technology Review: "The goal of the research is to explore an approach to the generation of new disease dog models for biomedical research.

"Dogs are very close to humans in terms of metabolic, physiological, and anatomical characteristics.”

US doctors are already trying to block myostatin in gene-therapy experiments as part of research into how to slow muscle degeneration in boys suffering from Duchenne muscular dystrophy.

The researchers have no plans to create the muscular dogs for pets - but that does not strike out others trying to do so in the future.

Another Chinese Institute, BGI, announced in September it had begun selling miniature pigs, created via gene editing, as novelty pets.

The list of animals already engineered using gene editing in China includes goats, rabbits, rats, and monkeys.

-Mirror UK