Reacción a "Serial mice cloning cannot be sustained indefinitely"

Since Dolly became the first mammal to be cloned from a fully differentiated cell in 1997, cloning has been seen as a tool with great potential in agriculture, livestock farming and species conservation. However, unlike plants or simpler animals, mammalian cloning faces significant limitations that are not merely technical.

Teruhiko Wakayama’s group in Japan, which in 1998 cloned the first mouse from terminally differentiated ovarian cells, has now published a study in Nature Communications summarising nearly 20 years of work. This work demonstrates that serial cloning in mice — that is, successive generations of animals born via nuclear transfer without sexual reproduction — significantly reduces the number of births from approximately 25 generations onwards, and after around 50 generations becomes incompatible with life. The authors note that the accumulation of damage to the genetic material of the transferred nuclei in each generation is the main cause of reproductive decline, although the animals are born apparently normal.

These findings highlight the importance of sexual reproduction in mammals. By mixing genetic material from two individuals, sexual reproduction helps repair harmful mutations and ensures the survival of the species, which explains why evolution has favoured this mechanism for hundreds of millions of years. Cloning is a useful tool in research and for certain biotechnological applications, but it should never cross the line into human use. Nature is always one step ahead of science.