Longevity: Selection

A common misunderstanding of research that uses selection to increase longevity is that the researchers propose to select on humans as a next step. But this approach is not only unethical, it would also be extremely inefficient. Humans have only a few generations each century, making the prospect of a significant response to selection on human longevity dim within the near future.

A more appropriate approach is to use selection on other animals as a tool to learn about the genetics and physiology of increased longevity, with a view to applying that knowledge to the postponement of human aging using pharmaceutical and other medical approaches. The prospects for such applications are now much greater with the complete sequencing of the human genome as well as the nematode and fruit fly genomes. Nematodes and fruit flies with increased longevity have been created by mutagenesis and selection. Some concerns have been raised about the value of the nematode mutants, but no such concerns apply to selected fruit flies. If genomic research applied to selected Drosophila reveals the specific loci controlling aging in fruit flies, there may well be homologues for those genes in humans. These homologues could be found by analyzing the full genomic sequences of the two species. Such human homologues would then be useful targets for research targeted at the problem of increasing human longevity. In this way, the humble fruit fly could, by way of selection, be of major medical value for increasing human lifespan, even though humans themselves would never be a target of selection.