Study: Your grandmother may be old, but that does not mean you'll be

"We know that people who are looking for their family are very interested in subject longevity, "said Cathy Ball, co-author of the study and scientific leader at Ancestry, a consumer genetics company that provides an online resource for family history.

To what extent do our genes contribute to our lifespan?

Previous studies suggest that genetic differences account for only 15% to 30% of longevity. It's the non-genetic differences between us – like how we eat and if we have a fatal accident – that explain why one person has a longer life than another.

Scientists at Calico Life Sciences LLC, a Google-funded company specializing in the biology of aging, teamed up with Ancestry researchers to study the genetic influence on lifespan. They badyzed anonymous family tree structures – or "genealogies" – including the year of birth, the year of death, the place of birth and the family ties for 439,361,203 people. These public family trees or genealogies were generated by Ancestry subscribers.

The size and size of the database allowed Calico scientists "to consult families over several generations, badyzing the longevity not only of family members, but also the laws," Ball wrote in a statement. email.

Using mathematical and statistical calculations, the team found that, for siblings and first cousins, heritability of longevity – or l '; extent of variation in the life span of individuals could be attributed to genetic variation. – was about the same as indicated in previous studies. Specifically, genes accounted for between 20% and 30% of longevity, with this estimate falling below 15% for opposite-bad family relationships.

The researchers also found that spouses had a similar life span – more than siblings of the opposite bad. One possible explanation is that spouses live in the same household and therefore share important non-genetic factors, such as diet and lifestyle in general.

The results of the study also showed that the brothers-in-law and the cousins ​​had a similar lifespan despite not being related to the blood and not sharing a living space.

What would explain this discovery? The authors think that a likely explanation is "badortative mating".

"Assortment mating is a mode of reproduction in which individuals with similar phenotypes breed more frequently than would be the case with a random pattern of reproduction," J. Graham Ruby, L & # 39; lead author of the study and a scientist and lead investigator of Calico wrote in an email

Of course, no one knows when their partner or potential partner will die. In this case, the reproduction by badortment would be based on secondary characters. For example, we know that income influences the life span because eating well and taking care of one's health are both somewhat related to money. The study suggests that if people from equal-income families tend to marry, this would explain similar longevity in non-family relationships.

Taking into account the choice of mating in their calculations, the researchers estimated that heritability accounted for no more than 7%

Your genes alone can not save you from an untimely death

Genetic Contributions to Longevity

New research adds to "existing clues to what leads to aging," said David Melzer, a professor of epidemiology and health at the University of Exeter's Faculty of Medicine in the UK and Professor at the Center on Aging of the University of Connecticut's Health Center in the United States.

Melzer, who did not participate in the study, wrote in an email, "it would have been nice to see" estimates of heritability in case of exceptional longevity because one think that centenarians have a higher degree of heritability than others for longevity.

Melzer and Luke C. Pilling, a researcher in genomic epidemiology at the Faculty of Medicine at Exeter University, also studied the genetics at the base of longevity.

"Our own recent estimate of the heritability of parental longevity directly from the common gene The variants present in 75,000 Britons accounted for 8.47%", implying a "total heritability of life span "of an individual between 10% and 20%, explained Melzer. This is "significantly higher" than the 7% or less suggested by the new family tree study, he said.

He noted that more than 20 genes had been identified for longevity.

"These include genes that interact with health behaviors, such as the nicotine receptor gene," Melzer said. He and his colleagues have also discovered genes that influence cellular senescence or the deterioration of individual cells. "It is likely that many variants of these genes are involved in life and aging," he said.

Ultimately, Ball said, "although there is a genetic component, this study shows that there is a major impact of many other forces in your life."

The findings suggest that anyone wanting a long life would do better to eat well and exercise, rather than rely on the good genes of grandfather.