Chinese scientists have successfully cloned two macaques, a first for nonhuman primates. It could lead to the creation of genetically uniform monkeys, which could be used to study diseases that result from genetic mutations.
David Royse | LedeTree
Scientists have used a particular technique to create cloned mice, cows, dogs and, of course, most famously, a sheep named Dolly.
But now, they’re through monkeying around.
Scientists in China have used the technique, somatic cell nuclear transfer, successfully for the first time in a non-human primate, creating two long-tailed macaques, according to a report published Wednesday in the journal Cell.
The scientists say the result could be a supply of genetically-identical monkeys that can be used in medical studies, where researchers could test what happens when one small part of the genetic code is changed.
“You can produce cloned monkeys with the same genetic background except the gene you manipulated,” one of the researchers, Qiang Sun, said in a press release. “This will generate real models not just for genetically based brain diseases, but also cancer, immune, or metabolic disorders and allow us to test the efficacy of the drugs for these conditions before clinical use.”
“As a species closer to humans, non-human primates are ideal animal models for studying physiological functions unique to primates and for developing therapeutic treatments of human diseases,” the authors wrote. “Animal models with genetic uniformity are often desirable but an inbreeding approach as used in generating rodent models is not practical for non-human primates because of their long generation time.”
The monkeys are named Zhong Zhong and Hua Hua and were born last month in Shanghai.
It’s the first time that cloning of primates using the somatic cell nuclear transfer, or SCNT, technique has resulted in live offspring.
Somatic Nuclear Cell Transfer is no longer the stuff of “wow” science as it was when it was first used to clone Dolly the Sheep back in 1996.
In fact, it’s now rather common with mice and other animals. The basic technique has also been used to create blastocysts, or pre-embryos, in primates – humans and monkeys – but never progressed to reproductive cloning, or taken all the way to live birth. Instead, it’s been used to harvest embryonic stem cells.
In SCNT, scientists first take an organism’s egg cell and remove its nucleus. They also remove the nucleus from a somatic cell, which is a cell other than a sperm or egg cell. That somatic cell nucleus contains the organism’s DNA. The somatic cell nucleus is then inserted into the egg cell. The host egg cell then begins to reprogram the somatic cell nucleus. The egg then is stimulated with a shock and begins to divide. After many divisions, eventually, it may form a blastocyst, or early stage embryo, containing a small number of cells. That embryo’s DNA is identical to the DNA of the original organism.
In the past, efforts to do reproductive cloning on monkeys using SCNT, that is, to take the work all the way through to, live birth, have failed.
The researchers, from the Nonhuman Primate Research Facility at the Chinese Academy of Sciences Institute of Neuroscience, experimented with different methods for transferring the nuclei, and different types of cells, using fetal monkey tissue instead of adult cells. They also were able to “reactivate” certain turned off genes after the nuclear transfer.
Within hours after the publication of the article in Cell, news outlets were raising the prospect that finally getting reproductive SCNT cloning to work in primates means it could technically be possible in humans.
“The technical barrier is now broken. In principle [this method] can be applied to humans,” the paper’s co-author, Muming Poo, was quoted as saying by the Financial Times. “However, we cloned [the macaques] to produce animal models useful for medicine, for human health. There’s no intention for us to apply this method to humans.”
Feature Photo: Qiang Sun and Mu-ming Poo of Chinese Academy of Sciences