2024-01-21 23:00:00
This 2024 feed your curiosity with National Geographic magazine for less than €6/month + GIFT NG Backpack Only 50 units!
Novelty! Subscribe to Gredos’ Historians of Greece and Rome collection. First issue, Thucydides for only €4.99.
Even those who did not live through the year 1996 easily recognize the name of Dolly: the sheep cloned at the Roslin Institute in the United Kingdom, which managed to live 6 years, approximately half the life expectancy of sheep of its breed. This milestone in biology is one of the most notable of the last century, not only because of its extravagance, but also because opened a debate about the possibility of cloning other species.
What unites us with our ‘cousins’ the gorillas
Since then, scientific interest in this controversial technique has continued to grow, with successful examples in cows (1998), pigs (2000) or rabbits (2002), among others. But what about people? At the moment, the idea of cloning humans has not been transferred to laboratories, because the technique used with Dolly seemed impossible to apply in primates.
However, in 2018, Chinese researchers led Qiang Sun of the Chinese Academy of Sciences in Shanghai described in the journal Cell the application of the procedure in cynomolgus macaques (Macaca fascicularis), from which two specimens were born, baptized as Zhong y Hua Hua.
Now, six years later, the same team of scientists has taken a further step in the research: after several failed attempts, an improvement in the technique that consisted of adding placental precursor cells has resulted in the successful cloning of another species of primate, the macaque Rhesus, with which we share 97.5% of the genome. The milestone has been published in the magazine Nature Communications and puts on the table the difficulties in achieving success in these experiments.
How did they manage to clone him?
On this occasion, scientists celebrate the survival for more than two years of the cloned Rhesus specimen, which they have named ‘Retro‘.
Reproductive cloning is scientifically called somatic cell nuclear transfer (SCNT), a nomenclature that gives clues as to how exactly this procedure is performed. Thus, following Dolly’s technical example and other cloned animals, Sun’s team obtained a genetic copy of the macaque Rhesus replacing the nucleus of an unfertilized egg with the nucleus of a cell from its body (somatic) – which contains a copy of your genetic code particular – to form an embryo in the “substitute prey”, in whose uterus it developed until birth.
National Human Genome Research Institute
Graphic explanation of the process of cloning a pig.
With this, although the cloning of this specimen has been achieved, the results in your efficiency They are, as in the case of crab-eating macaques, very short. In 2018, they created 109 embryos, transferred 79 of them to 21 females and only achieved six pregnancies, of which only two specimens were born. And now, they created 113 embryosthey transferred 11 to seven females and achieved two pregnancies, although a single birth: the one of ‘Retro‘.
In this sense, the fact that the data have not deviated from those obtained in Dolly’s cloning brings to light not only lack of ethical justification of applying the procedure in humans, but also the multitude of technical difficulties that presents this process.
This is exactly what Lluís Montoliu, a researcher at the National Center for Biotechnology (CNB-CSIC) and at the CIBERER-ISCIII, has expressed: “Both the cloning of the crab-eating macaque and that of the Rhesus monkey demonstrate two things. First of all , that is it possible to clone primates. And, secondly, and no less important, it is extremely difficult to be successful with these experiments, with such low efficiencies, again ruling out cloning of human beings“.
What would cloning be used for?
Taking into account the broadest sense of the term cloning – which includes reproductive, therapeutic and genetic, according to the classification of the National Human Genome Research Institute – it could be said that it is a promising technique, although with few successful results to date, and with endless debates to resolve before it can be applied regularly.
Shutterstock
We share 97.5% of the genome with macaques Rhesus.
The possible uses of reproductive cloning, of which Dolly and the macaques of 2018 and 2024 are examples, relate to benefits for the fields of medicine and agriculture: for example, to evaluate new drugs and treatment strategies, or to create copies of animals with ideal agricultural characteristics, such as high milk production or lean meat.
On the other hand, another controversial use of this procedure has to do with the deextinction: that is, with the return to life of extinct species to save biodiversity. And yes, although it seems like an idea taken from a science fiction book, it is a process that was already carried out with partial success in the year 2000: Celiathe last specimen of bucardo (Capra pyrenaica pyrenaica) in Spain, was born (or, rather, reborn) alivebut unfortunately a lung malformation caused him to drown before reaching 10 minutes of life.
With all this, the macaque Rhesus cloned by Sun and his team is just one more example of the dizzying progress of a technique that, due to the difficulties and debates it presents, not yet widely usedbut whose study could continue to offer new findings in genetics.
#Retro #cloned #macaque #lives #adulthood