Cloned monkey, the first to survive two years: scenarios against infertility are opening up

Chinese scientists have cloned a monkey, a rhesus macaque, who 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 in 1996Dolly the sheep
(the first mammal to be successfully cloned).
The result was obtained byChinese Academy of Sciences, which had already cloned two monkeys in 2018. So far for animals, especially monkeys (especially i 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 one 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, he told ANSA Carlo Alberto Redi, president of the ethics committee of the Veronesi Foundation and member of the Accademia dei Lincei. 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 the understanding infertility, to the protection of endangered animalsto the understanding of 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 “the 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 to overcome infertility problems in couples given that, as Redi recalls: In human beings, over 50% of natural pregnancies do not occur due to failure to implant of the embryo in the uterus.

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