Many factors influence how long you live, such as diet, exercise, smoking, drinking, environment and other variables. It also helps not to get hit by a dump truck. But what about your genes? That has been a contentious question for decades.

A new study points to a larger role for genetics than previous research had indicated, estimating the contribution of genes to determining human lifespan at about 50%. That is roughly double ?what prior research concluded, and it mirrors the findings of lifespan studies in laboratory animals.

¡°Lifespan is undoubtedly shaped by many factors, including lifestyle, ?genes ?and, importantly, randomness ¡ª take for example genetically identical organisms raised in similar environments that die at different times,¡± said ?Ben Shenhar, a doctoral student in physics at the Weizmann Institute of Science in Israel and lead author of the study published on Thursday in the journal Science.