Kim does not believe that the transcription factors are programmed to trigger aging. Instead, he speculates, their function becomes unbalanced as worms get older. Evolution, after all, selects for genes that help individuals reproduce, but once organisms have passed breeding age, they are no longer subject to its control. “Entire biological systems drift away when nature doesn’t care anymore,” Kim notes. ELT-3, ELT-5 and ELT-6 may play an important role in the development of young worms, but after their job is done, their function could go awry—and this “developmental drift,” as Kim calls it, could actually cause aging.
The study does not prove that aging in worms is driven only by developmental drift, Kennedy observes. Both damage accumulation and drift could play a role, and other genetic circuits could also be involved. But the paper certainly gives scientists “something else to think about with regards to what might be driving the aging process,” he points out. “It brings to the forefront a new hypothesis that can be tested in more detail.”
What could these findings mean for people? If aging is primarily a genetic process, conceivably it could one day be preventable. No one yet knows, however, whether the human counterparts to the ELT genes—called GATA transcription factors—might also be involved in normal aging, but it is a question Kim and his colleagues hope to address soon. “We know how human development works,” Kim says. “Now we just have to find out which of these pathways are not working as well in old humans.”
Note: This article was originally printed with the title, "Rethinking the Wrinkling".
This article was originally published with the title Rethinking the Wrinkling.