Five monkeys cloned from a single monkey with genes edited to cause “diseases” have been born in China.

The highly controversial experiment is the first step to creating a diseased “monkey population” for animal testing – but has been branded “monstrous” by experts speaking to The Sun.

The monkeys were created using roughly the same technique as Dolly the Sheep, a famous clone sheep born in the late 90s.

They were cloned from a monkey whose own genes had been edited to remove a vital gene that regulates the body’s circadian rhythm.

Scientists hope that they can eventually create a diseased “monkey population” of clones that can be used for animal testing – a highly controversial aim.

“The use of primates in scientific research and testing is a matter of extreme concern to the animal protection community and to members of the public around the world,” said Dr. Penny Hawkins, the RSPCA’s Head of Research Animals, speaking to The Sun.

And Dr. Julia Baines, Science Policy Advisor at PETA UK, told us: “Genetically manipulating and then cloning animals is a monstrous practice that causes animals to suffer.”

Researchers at the Chinese Academy of Sciences Institute of Neuroscience tinkered with a specific gene in the original donor monkey.

The gene is BMAL1, which helps regulate the circadian rhythm – but scientists made it inoperative using gene-editing.

This donor monkey’s cells were then used to clone five new monkeys.

It’s the same technique used to create Zhong Zhong and Hua Hua – the first two cloned monkeys – last year.

During the early part of the experiment, scientists knocked out the BMAL1 gene on several monkeys, which then exhibited symptoms (also known as phenotypes) related to a circadian disorder.

This includes reduced sleep time, elevated movement at night, dampened circadian cycling of blood hormones, increased anxiety and depression, as well as schizophrenia-like behaviors.

“Disorder of circadian rhythm could lead to many human diseases, including sleep disorders, diabetic mellitus, cancer and neurodegenerative diseases,” said Hung-Chun Chang, a senior author on the studies, which were published in the National Science Review.

“Our…monkeys thus could be used to study the diseases pathogenesis, as well as therapeutic treatments.”

Scientists removed the nucleus from a monkey egg cell and replaced it with the nucleus from a donor monkey cell.

This reconstructed egg then developed into an embryo, carrying the genes of the replacement nucleus.

The embryo was then transferred to the womb of a surrogate female monkey mum, which gave birth to the cloned monkey.

“Our approach is to perform gene-editing in fertilized embryos to first generate a group of gene-edited monkeys and then select one monkey that exhibits correct gene-editing and most severe disease phenotypes as the donor monkey for cloning by somatic cell nuclear transfer,” said Qiang Sun, a senior author on the paper.

“We believe that this approach of cloning gene-edited monkeys could be used to generate a variety of monkey models for gene-based diseases,” Qiang added.

This included “many brain diseases, as well as immune and metabolic disorders and cancer.”

The group wants more macaque clones carrying disease-causing gene mutations to be generated in the coming years.

We spoke to Mu-ming Poo, Director of the Institute of Neuroscience at the Chinese Academy of Sciences, who said that work was ongoing.

“We are working on gene-edited and cloned monkeys with Alzheimer’s disease, Parkinson’s disease and Angelman’s syndrome (a form of autism spectrum disorders),” Mu-ming told The Sun.

“All could have genetic origins.”

Mu-ming said the team wouldn’t try to clone other animals – focusing on monkeys for animal research purposes.

“[The] cloning approach will provide genetically uniform monkeys for models of human diseases and because monkeys are the closest experimental animals to humans,” the researcher explained.

“They are the most suitable models for developing therapeutics for human diseases, such as pre-clinical tests of the efficacy of drug candidates.

“The use of monkeys rather than mice as disease models will greatly increase the success rate of clinical trials, each of which requires more than one billion of cost and involves thousands of human subjects.”

But the experiments have drawn ire from animal welfare campaigners who blasted Chinese scientists over the diseased monkey clones.

“There are huge ethical and animal welfare concerns about this research,” the RSPCA’s Dr. Penny Hawkins told us.

“Primates are intelligent animals, not just research tools. The procedures used to alter the monkey’s genes cause suffering and distress, plus the effects are not always predictable.”

“This gene editing is leaving monkeys with distressing physical and mental conditions and we would seriously question the justification for creating large numbers of ‘models’ of serious human diseases in these remarkable, sensitive animals.”

“We are expected to assume that human patients will benefit from these experiments, but any new medicines would be years away and there is no evidence that yet more animal ‘models’ are necessary in developing these treatments.”

PETA UK’s Dr. Julia Baines told us that the Chinese experiments were “an abomination,” causing monkeys to be “born into a life of deprivation and to be plagued with symptoms including anxiety, fear, depression, behavior associated with schizophrenia and sleep deprivation, each a horror on its own.”

“As if that weren’t enough, in these twisted studies, experimenters plan to clone only those individuals who show the most severe forms of suffering,” Baines continued.

“To make matters worse, these abused monkeys won’t accurately mimic human disease, as these conditions aren’t caused by one single genetic mutation.”

“Genetically manipulating and cloning animals won’t solve human medical problems but will certainly cause these intelligent and sensitive fellow beings a lifetime of misery.”