Scientists successfully generate a genetically cloned golden monkey by providing defect-free embryonic stem cells.
Chinese scientists clone a golden monkey through the replacement of defective embryos with healthy ones, according to Live Science. This advanced technique could significantly increase the success rate of cloning. The monkey, named ReTro, is currently 3.5 years old, remaining healthy and developing well, as reported by co-author Qiang Sun, the chief neuroscientist at the Center for Brain Science and Intelligent Technology of the Chinese Academy of Sciences.
Researchers had previously attempted to clone golden monkeys, but this is the first time they have successfully used the method of nuclear transfer, involving replacing the nucleus of a fertilized egg with a nucleus taken from the somatic cell of another individual. Somatic cells include all cells in the body except reproductive cells. An earlier attempt to clone golden monkeys through somatic cell nuclear transfer resulted in the birth of a live offspring, but it died only 12 hours later.
The rhesus macaque (Macaca mulatta) is widely used in laboratories and medical research due to its close genetic proximity to humans. Cloning this monkey species can help establish non-human primate models with a consistent genetic background and identical gene types in a short period, according to Sun. This aids researchers in isolating any genetic influences when testing drugs. The cloning process is detailed in a study published on January 16 in the journal Nature Communications, bringing us closer to improving cloning efficiency in primates and other mammals.
Scientists have utilized somatic cell nuclear transfer to clone a variety of mammalian species such as monkeys, sheep, livestock, and dogs. However, most cloned embryos do not survive until birth, often due to developmental and structural abnormalities. Approximately 1-3% of attempts result in live births through traditional cloning methods, with slightly higher success rates in livestock (5-20%).
To address this issue, Su and colleagues replaced the normally developing somatic cell cluster in the cloned embryo with cells similar to those from a normal embryo. These so-called trophectoderm cells form a healthy placenta, providing the cloned embryo with nutrients and oxygen during development. The experiment led to the birth of a healthy male golden monkey in 2020. Since developmental abnormalities in the placenta are common in all cloned mammalian species, the research team anticipates that this new method could be applicable to other mammalian species and non-human primates.
