This recent analysis, spearheaded by investigators at the Weizmann Institute of Science in Israel, indicates that genetic factors are responsible for approximately 55 percent of the variability observed in human lifespans.

This figure significantly surpasses earlier estimations, which typically ranged from around 20-25 percent, with some studies even suggesting as little as 6 percent influence from genetics.

These findings carry substantial implications for our comprehension of genetic aging processes and the ongoing pursuit of genes specifically linked to longevity, as stated by the researchers.

“For an extended period, the prevailing belief was that human lifespan was shaped almost exclusively by non-genetic influences, casting considerable doubt on the role of genetics in the aging process and the practicality of pinpointing genetic markers for longevity,” explains molecular biologist Ben Shenhar of the Weizmann Institute of Science.

The diverse array of circumstances leading to the end of human life can be broadly categorized into two types: intrinsic and extrinsic. Intrinsic causes of death stem from internal biological mechanisms such as aging and genetic predispositions, whereas extrinsic causes encompass external factors like accidents, infections, and other environmental influences.

Historically, much of the data employed in prior investigations lacked the granular detail necessary to differentiate precisely between these causal factors.

In this study, the research team examined data from thousands of twins, notably including siblings who were raised separately—a variable not previously factored into studies on lifespan heritability.

Twin studies are instrumental in genetic research, enabling the differentiation of genetic influences on an individual from post-birth environmental factors, including lifestyle choices, dietary habits, and educational background.

Extrinsic causes of mortality were systematically excluded through the application of mathematical models of mortality, which posit that the older an individual becomes, the more likely death is to be attributed to intrinsic factors.

The study’s results not only demonstrated a strong correlation with real-world observations but also presented the new 55 percent estimate, which aligns more closely with established figures for the genetic influence on other physiological characteristics, such as human height.

“This significant level of heritability is comparable to that observed in most other complex human traits and to the heritability of lifespan in different species,” note the authors in their published research.

While this new research does not necessarily contradict previous findings, it strongly suggests that the datasets used in earlier studies may not have fully captured the complete picture regarding the interplay of factors influencing lifespan and mortality.

The researchers are now focused on validating their conclusions using contemporary datasets that offer improved methods for distinguishing between various causes of death. The revelation of genetics’ substantial role in determining lifespan naturally prompts further inquiries into which specific genes exert the most significant effects and the mechanisms by which they operate—these represent promising avenues for future investigation.

“If heritability is indeed as high as our findings indicate, this provides a powerful impetus for the search for gene variants contributing to extended lifespan. This pursuit is vital for understanding the fundamental biology of aging and, potentially, for developing therapeutic interventions,” states Shenhar.