Recent research reveals that genes play a significantly larger role in determining human lifespan than earlier studies suggested. A team from the Weizmann Institute of Science in Israel found that approximately 55 percent of the variation in lifespans can be attributed to genetic factors. This finding contrasts sharply with previous estimates, which ranged from 20 to 25 percent, and in some cases, even as low as 6 percent.
The study, which analyzed data from thousands of twins, has important implications for understanding the genetic basis of aging. According to Ben Shenhar, a molecular biologist at the Weizmann Institute, “For many years, human lifespan was thought to be shaped almost entirely by non-genetic factors, which led to considerable skepticism about the role of genetics in aging.”
Insights into Lifespan Determinants
Lifespan can be influenced by both intrinsic and extrinsic factors. Intrinsic factors include genetic predispositions and the natural aging process, while extrinsic factors involve accidents, infections, and other external causes. Previous research often lacked detailed data on causes of death, making it difficult to ascertain the relative impact of genetics versus environmental influences.
The innovative approach taken by the researchers involved analyzing data from twins, including those raised apart—a factor that had not been considered in many prior lifespan heritability studies. This twin data is essential for isolating genetic influences from post-birth factors like lifestyle choices and diet.
Mathematical models of mortality were employed to filter out extrinsic causes of death, revealing that as individuals age, intrinsic factors become increasingly significant. The new findings align closely with existing estimates regarding the genetic basis for variations in other human characteristics, such as height.
Future Research Directions
While this research does not entirely contradict earlier studies, it suggests that previous analyses may not have captured the full complexity of how genetics influences lifespan. The researchers aim to further validate their conclusions by examining modern datasets that provide a clearer understanding of different causes of death.
The significant heritability of lifespan raises essential questions about which specific genes contribute to longevity and the mechanisms through which they operate. Shenhar notes the implications for future research, stating, “If heritability is high, as we have shown, this creates an incentive to search for gene variants that extend lifespan, in order to understand the biology of aging and, potentially, to address it therapeutically.”
The findings were published in the journal Science, marking a noteworthy step in the ongoing exploration of genetic factors in human health and longevity.
