By Ginés Morata
The extremely high degree of conservation of fundamental biological phenomena throughout the animal kingdom allows us to speculate on the possibility of manipulating processes only recently considered inaccessible to human intervention. One of the fundamental paradigms of human society and culture is the idea that aging and death are inevitable biological processes. The supposition is that there is internal programming that establishes the maximum lifespan of members of each species within a relatively narrow range.
During the twentieth century, the average human lifespan increased considerably, due mainly to improved living conditions, hygiene, and medical progress. Even so, the estimated maximum lifespan is about 120-125 years. Could this limit be surpassed? That is a subject that has received considerable attention in international science magazines (Nature 458, 2008, 1065-1071), fundamentally because of recent discoveries directly related to the genetic programming of lifespan.
The fundamental fact is that, in both the nematode worm, Caenorhabditis elegans, and in the Drosophila fly, various genes have been identified whose function is directly related to the aging program of those species. Given the ease with which those organisms can be genetically manipulated, it has been possible to substantially prolong the life of individuals from those species. In the case of nematodes, lifespan has been successfully multiplied by six- or even seven-fold. If this were extrapolated to the human species, it would offer an average human lifespan of some 350 years, and some individuals would live over half a millennium.
Mutations in the human species that affect the activity of the insulin path have also been detected in individuals who are over one hundred
What is important about these discoveries is that the aging genes identified in the nematode worm and in Drosophila are also present in the human species. The most studied of those genes, called DAF-16 in worms and FOXO in Drosophila and humans, is related to the insulin path and some of the variant forms of FOXO appear to be particularly frequent in individuals over one hundred years old. Mutations in the human species that affect the activity of the insulin path have also been detected in individuals who are over one hundred. DAF-16/FOXO has been cloned and genetically modified worms have been created in which alterations in the levels of this gene’s functions result in alterations that double the lifespan of those worms. The fact that such results can be obtained by altering just one gene illustrates the potential of such techniques. As we mentioned above, this gene is present in our own species, which suggests the possibility that its manipulation could be used to modify the lifespan of human beings.
Read more about this issue on Ginés Morata’s article The Century of the Gene. Molecular Biology and Genetics
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