Although longevity tends to be passed on within the family, the effect of genes on longevity is far less than we previously knew. The study has been published in the American Journal of Genetics.
Graham Ruby, lead author of the study, said: “It is possible for us to learn more about the biological aging process from the perspective of human genetics, but if the heritability of lifespan is low, our understanding of this field will change. “Calico Life Sciences, where Ruby works, is exploring the mystery of biological aging. They collaborated with scientists at the online genealogy resource site Ancestry to assess the heritability of human lifespans using the site’s shared genealogy data.
The heritability of longevity is a measure of the variability of the characteristic of longevity. It can be answered by genetic differences. The opposite is non-genetic differences such as lifestyle, social and cultural factors, and accidents. Prior to this, scientists speculated that the heritability of human lifespan is 15% to 30%. “Collaborating with Ancestry has enabled this latest study to explore life more deeply with unprecedented amounts of data,” said Katherine Barr, chief scientific officer of the Ancestry website’s science team.
Before cooperating with Calico’s research team, Ancestry’s website removed all identifying information in the database, leaving only the date of birth, date of death, place of birth and family relationships. In the end, the researchers screened a pedigree that included more than 400 million people, so that they could assess the heritability of life from the pedigree using similar life spans among relatives.
In their research, researchers have used a new method that combines mathematics and statistics. They found that heredity between siblings and cousins was about the same as previously reported. But they also noticed that there was a link between the study subjects and the life span of their spouses. This may stem from their common living environment.
In addition, researchers have found that although they are not blood relatives or usually live in different families, their brothers and cousins have similar life spans. The huge amount of data also allows the research team to explore the longevity correlations of more distant relatives, including in-law relationships.
Researchers discovered selective mating when analyzing the data. Ruby said: “Selective mating means that people tend to choose a spouse with similar characteristics to themselves, and this is also very important for life.” Of course you can’t guess the life of a potential spouse, so you must refer to other factor.
The basis for this spouse selection is genetics or socio-culture. In the case of non-hereditary factors, income affects life expectancy, and rich people tend to marry other rich people. Genetics has a similar effect. For example, taller people choose taller people, and height is also related to life to some extent.
By removing the effects of selective mating, the researchers found that the heritability of lifespan is likely to be less than 7%, or even lower. So how long you can live has nothing to do with your genes.