Comparing the face of an average 47-year-old (L), and 70-year-old (R).
Image credit: Fan Liu
Humans have an in-built, subconscious ability to make a snap decision based on someone's face.
This has served us well throughout evolutionary history; reading facial expressions could mean the difference between a friendly encounter and a battle to the death.
Beyond facial expressions of anger and fear, we are also predisposed to judge people by their age.
Someone younger might be perceived as a rival or be chosen as a potential mate over someone who looks less likely to be fertile.
A research team from the Netherlands has, for the first time, identified a gene that is partly responsible for a more youthful appearance.
Although one single gene on its own can not explain the intricacies of aging, its discovery may open doors to new avenues of research.
The team, from Manfred Kayser of Erasmus Medical Center University Medical Center, Rotterdam, investigated more than 8,000,000 DNA variants as part of their search.
The team's work is a landmark finding in the field of aging and genetics.
What makes someone appear older?
Earlier studies have demonstrated that how old someone appears is a combination of genes and their environment. Research has also shown that the perceived age of an individual's face predicts a person's general health and mortality.
There seems to be a link between how old someone is perceived to be and how healthy they are, regardless of their chronological age.
For the current study, Kayser joined forces with David Gunn, based at the company Unilever. The team used genome data from 2,600 older adults and found that one gene correlated well with perceived facial age; the gene is known as MC1R.
"For the first time, a gene has been found that explains, in part, why some people look older and others younger for their age."
Individuals who carried a particular variant of MC1R were perceived to be 2 years younger than their actual age. These effects were independent of chronological age, sex and the amount of wrinkles.
This finding is also backed up by the results of two other large-scale studies investigating similar outcomes.
The role of MC1R
MC1R holds instructions for the production of a receptor called melanocortin 1. This receptor plays a role in the coloration of skin, hair, and eyes. A certain variant of the gene is commonly found in individuals with fair skin, red hair, and freckles. A reduction in function of the MC1R gene has been linked to an increased sensitivity to the sun and associated skin cancers.
The MC1R gene is also known to play a number of roles, including inflammation responses and repairing damaged DNA. This might be the key to understanding how the variant appears to keep people looking more youthful.
The researchers note that the actions of MC1R are just a small part of a large web of interactions. Many pathways are likely to be involved. They also believe that this type of research could eventually generate more of an understanding of how genes influence the aging process in general.
"We believe that using the perception of age is one of the best and most exciting ways to measure how 'well' people are aging, which we hope will lead to further breakthroughs in aging and health research in the near future."
The current study is of a relatively small size, and the authors hope to increase numbers in future investigations, they say: "Much larger sample sizes are now required to reveal additional gene variant effects on perceived age as well as their effects in younger and non-European populations."