Society’s quest for a fountain of youth is as strong as ever, and today’s scientists are looking for clues in a new place: the genomes of mammalian relatives. Among mammals, conventional wisdom says that the smaller the body, the shorter the life span. Anyone who’s ever brought home a hamster can attest to their short life spans, while scientists have verified that some whales can live for more than 200 years.
What interests scientists, of course, is where conventional wisdom breaks down. Two types of mammals—bats and naked mole-rats—have tiny bodies but live for decades. During the Advances in Genome Biology and Technology conference last month, researchers explained how they’re trying to tease apart the biological mystery of longevity by studying these creatures.
Emma Teeling, a scientist at University College Dublin who finds bats beautiful, described a painstaking effort to study a specific population over a long period. Bats don’t do well in captivity, so Teeling’s crew conducts their investigation in the wild. They have targeted a French colony of the long-lived bat species Myotis myotis, catching bats as babies and tagging them so the same individuals can be recaptured and analyzed each year. For the past decade, scientists have taken vanishingly small DNA samples from each bat to build a remarkable resource representing the biological changes of distinct members of the colony over time.
One of the most surprising findings is that the DNA of these bats doesn’t behave like that of other mammals. At the end of each chromosome, whether you’re a human or a mouse, there’s a protective cap called a telomere that shrinks with age. (Teeling likened it to the plastic end on a shoelace; once lost, the lace frays.) It is widely accepted that shrinking telomeres are associated with the symptoms of aging—and that this happens consistently across species. But when Teeling and her colleagues inspected these bat telomeres over time, they found them virtually unchanged. After 10 years, the telomeres looked as good as they did when the bats were babies. While their work is ongoing, preliminary analysis found that these bats have evolved more active DNA repair genes than other mammals. It’s a tantalizing discovery that may point the way toward methods to repair our own telomeres, possibly preventing the effects of aging.
Another presentation from Margaret Roy at Calico Life Sciences, the Google-backed company focused on life extension, centered on the naked mole-rat. These hairless rodents can live for 30-plus years—for most of that time appearing healthy without obvious signs of aging. Roy said the creatures fit nicely into Calico’s research into the biology of aging, as well as related diseases such as cancer, diabetes, and Alzheimer’s. This project is still underway, with analysis and key discoveries still to come.
Naked mole-rats also have an unusually high resistance to cancer, further reason they interest scientists. It all underscores the importance of maintaining biological diversity as we just scratch the surface of what nature might teach us about how to improve human life.
Techonomy has reported before on the life extension movement, but the work of these two groups of scientists suggests a clear scientific path to finally understanding longevity or even to finding new ways to live without aging. Of course that’s still, at best, a really long way off.
