Complex interactions may matter most for longevity, not single factors
A study of the biology of aging shows that interactions among diet, mitochondrial DNA, and nuclear DNA appear to influence lifespan at least as much as single factors alone. The findings help to understand the underlying mechanisms of aging and explain why studies of single factors sometimes produce contradictory results.
“I think the main lesson is that these interaction effects are as significant or important as the [single] effects, such as diet effects alone or genetic effect alone,” said David Rand, professor of biology and senior author of the study published in the journal PLoS Genetics (open access).
“Traditionally that’s what people have focused on: looking for a gene that extends longevity or a diet that extends longevity.” When researchers have looked at single or even pairs of factors in a wide variety of organisms, they’ve made many valuable findings about the biology of aging, Rand said. But sometimes scientists have been unable to replicate each other’s findings in seemingly similar experiments.
Often this is attributed to mysterious “background effects,” presumably other genes that were not properly accounted for. The new study chose to put such background effects into the foreground to examine dietary effects on aging in several panels of different nuclear and mitochondrial genetic pairings, the biologist say.
The study’s results suggest that many observed effects of calorie or diet restriction or different genes on lifespan may depend on a more intricate context than has been understood so far.