New research published today in *Science* suggests our genetic makeup plays a more considerable role in determining lifespan than previously understood,accounting for over 50% of longevity-a meaningful increase from earlier estimates that placed it closer to 20-25%.[[1]] The international study, involving scientists from Israel, Sweden, China, and the Netherlands, reframes the long-held debate over nature versus nurture, revealing a near-equal contribution from both genetics and lifestyle factors in how long we live. This finding underscores the growing understanding of epigenetics – and how daily choices impact gene expression.
The influence of genetics on how long we live is more significant than previously thought, according to new research. Earlier studies estimated heritability between 20-25%, with some suggesting as low as 6%.
How much does longevity depend on our genes? Scientists are increasingly understanding the interplay between inherited traits and environmental factors. Think of it as a puzzle with two colors: blue representing genetic inheritance, and red representing the exposome – the totality of external influences, including chemical, physical, psychological, and social elements, that impact our DNA. A study published January 31, 2026, in Science demonstrates that the heritability of human lifespan, excluding deaths caused by external factors like accidents or infections, is just over 50%. This suggests that genetics and lifestyle choices carry roughly equal weight in determining how long we live.
The research, conducted by scientists at the Weizmann Institute of Science (Israel), Karolinska Institutet (Sweden), Westlake University (China), and Leiden University (Netherlands), resolves a long-standing debate: is our lifespan primarily determined by genetics or lifestyle? Previous research had estimated heritability at 20-25%, with some studies suggesting as little as 6%. This led to the belief that environmental factors were dominant. However, the new findings indicate that genetics and environment play equally important roles.
To understand how genes and environment interact, it’s important to consider epigenetics – the study of how external factors can modify gene expression without altering the underlying DNA sequence. This involves processes like DNA methylation, where chemical markers attach to specific parts of the genome to silence certain genes. The collection of these chemical markers is known as the epigenome.
DNA methylation is heavily influenced by the environment and serves as a “biological clock.” Analyzing methylation patterns can reveal a person’s true age, which may differ from their chronological age. As we age, the regulation of epigenetic processes becomes less efficient, leading to changes in cellular function and ultimately, organ dysfunction. This is what we call aging.
While we can’t currently reverse this process to regain youth, we can slow it down. This power lies in our daily behaviors: eating a healthy diet in appropriate portions, exercising regularly, getting enough sleep, minimizing stress and exposure to harmful substances like smoke, alcohol, and pollutants, receiving recommended vaccinations, and following age-appropriate screening programs. Equally important is recognizing that humans are social creatures. Cultivating friendships and engaging in community activities are also vital. Those who have inherited longevity traits are fortunate, but our daily choices can significantly extend our lives. Our story isn’t solely written in our genes.
