How old we look is not just about counting the wrinkles at the corners of our eyes or the sunspots that dapple our skin. Scientists may have discovered the first gene responsible for how young—or old—we look to others. 

New genome-sequencing research suggests white European people with two copies of variant forms of MC1R, a gene linked to pale skin and red hair, have faces that appear up to two years older than those who are the same age but don’t have both copies. Having only one variant copy of the gene gives people the appearance of looking about one year older on average, the team of Dutch and British researchers concluded. The scientists also discovered that this new genetic association held true even after accounting for factors like wrinkling, reported sun exposure and varied skin tone (pale versus olive).

Of course, even genetic instructions have their limits. “If you now want to use this to blame your genes for looking much older, it won’t work,” says co-senior author Manfred Kayser, a forensic molecular biologist at Erasmus University Rotterdam. Looking a couple years older than someone is not a large difference on its own, he says. Yet combined with other factors such as sun exposure and smoking, genetic factors could make a sizable dent in the youthfulness of one’s appearance. 

Earlier scientific findings suggested that how old a person’s face appears is influenced by both genetic and environmental factors in roughly equal amounts, but until now researchers had not confirmed which genes contribute to the appearance of youth—although MCR1 had been a top candidate because prior work had linked it to factors such as skin aging. The new findings, which involved scouring human genomes and human perceptions, were published Thursday in Current Biology.

The research team’s hunt for such age-related genetic associations involved studying more than 8 million single nucleotide polymorphisms—changes of one nucleotide for another at a particular spot in the DNA—in 2,693 individuals. This can be a time-consuming process, the team quickly learned.

Then, to make connections between genes and age perceptions, the study team asked around 30 white British employees of Unilever—a company that produces household goods and consumer items including soaps and ice cream —to look at front and side facial images of each of the individuals in the study, and to record how old the person appeared.  The authors then statistically adjusted for factors including sun exposure levels, wrinkling, age and sex, and found that their MCR1 findings persisted. That means the pale skin already associated with MCR1 variants and its vulnerability to sun damage cannot explain away the appearance of older age. The European researchers then went on to confirm their findings with two more smaller sample groups. (Unilever staff are co-authors on this paper, although no particular beauty or household product was being evaluated.)

“This finding is a good first step,” says Stanford University dermatologist Anne Lynn Chang, who was not involved in the work. But she says further evaluation should also correct for factors such as differences in body mass index among the photographed people, and whether they have health issues like strokes or vascular conditions that could make them appear older.

To some extent, age perception is certainly in the eye of the beholder. For example, multiple studies have suggested that when estimating age across cultures or race, perceptions can differ. However, the latest study sidestepped some of this concern by having both judges and photographs from the same general group, white Europeans.

In everyday life, we also know that age evaluation involves more than a pretty and youthful face. Often, quick judgments about age also include the full person—hair color, bearing and gait, and those factors were not included in this study. But next time you notice a particularly youthful face in the crowd, perhaps it is worth considering what genes might have to do with it.