at Silvia Turin
Chinese scientists perfect the technique used for Dolly the sheep and manage to solve the problem that prevented development, providing a healthy placenta to the embryo. Redi: The future is not human cloning but the fight against infertility and other diseases
Chinese scientists have cloned a monkey, a rhesus macaque, which for the first time lived for over two years in good health.
I study
This is communicated by a scientific article just published on Nature Communications which traces the results of the success of the technique used, the same one that cloned Dolly the sheep in 1996 (the first mammal to have been successfully cloned).
The result was obtained by the Chinese Academy of Sciences, which had already cloned two monkeys in 2018. Until now, animals, especially monkeys (particularly rhesus macaques), were unable to survive: in only one case an embryo survived birth for a few hours.
Cloning as for Dolly but with a step forward
Now the cloned monkey is called ReTro and managed to survive thanks to a healthy placenta. This is why it is called Re which stands for rhesus and Tro which stands for trophoblast, the embryonic structure that gives rise to the placenta.
The method used consists of the nuclear transfer technique: the nucleus of an adult cell (which contains the DNA) is transferred into an oocyte deprived of its nucleus; in this way the cell is induced to regress to a primitive and undifferentiated stage, to the point of being able to give rise to a new embryo when transferred to the uterus.
Problems arose in the development of the cloned embryos and the size of the placenta. In this new experiment, Chinese scientists managed to identify the stage of the embryo where the difficulties developed and intervened by combining cloning with in vitro fertilization. From the first they took the embryo and from the second a healthy placenta (a trophoblast obtained through fertilization between gametes).
The biological problem that prevents embryonic development has been discovered
a fundamental stage in regenerative medicine, Carlo Alberto Redi, president of the ethics committee of the Veronesi Foundation and member of the Accademia dei Lincei, told Ansa. Redi explained the usefulness that this new method can have: No one on Earth can reasonably think of using this technique for the purposes of human cloning and he specified that a very important model has been created for biology and medicine which could have implications for many scientific fields. : from understanding infertility, to saving endangered animals, to understanding many mitochondrial diseases. Never before – said Redi – has so much data been collected on the period of embryonic development preceding the implantation of the embryo in the uterus and it has been understood that “extra-embryonic structures do not function”. That is to say that the key is no longer the sequence of the DNA bricks, but what is “written” on the bricks during embryonic development. It’s not just genetics, but epigenetics.
Future repercussions on infertility or mitochondrial diseases
These studies shed light on a previously unknown area: the failure to implant the embryo at the basis of reproduction and the biological problem that gives rise to it. The discovery could be interesting for overcoming infertility problems in couples given that, as Redi points out: In humans, over 50% of natural pregnancies do not occur due to the failure of the embryo to implant in the uterus.
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January 16, 2024 (modified January 16, 2024 | 8:11 pm)
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