Forensic scientists are one step closer to predicting a suspect’s hair color from just that person’s DNA, after discovering more than 100 new genes that influence a person’s hair color.
A test based on new genetic markers has been 10-20% more accurate than currently used forensic tests, and is very reliable for blond or dark hair. , while brunettes and blondes proved more difficult to predict, the researchers said.
“If someone leaves blood at a crime scene, from that person’s DNA you can tell whether they have dark hair or blonde hair with about 90 percent certainty,” said Tim Spector, lead author of the work. research at King’s College London.
A person’s hair color is one of the most heritable traits in their appearance, with studies on twins showing that genetics affects up to 97% of hair color. So far, scientists have known only about 13 genes that affect the brightness of a person’s hair color.
After studying the DNA of nearly 300,000 people, researchers from King’s College and the medical center of Erasmus University (Erasmus MC) in Rotterdam have discovered 124 genes that contribute to hair color, either directly. affect the production and distribution of melanin naturally or through other biological mechanisms, many of which are still poorly understood.
A person’s hair color can reveal many things – (Image: Pinterest).
The large number of newly discovered hair color genes help explain 35% of cases of blond hair, 25% of blonde hair and 26% of black hair, according to the study, just published in the journal Nature Genetics.
It is possible that hundreds of other genes also affect hair color in ways too small for scientists to detect.
One factor that complicates the forensic examination of hair color is the tendency commonly seen in babies who are born blonde but turn brown several years later. Although the change itself could be caused by a gene, the researchers were unable to detect which gene is responsible for the effect.
“We know that some blondes turn brown, but we don’t know why,” said Manfred Kayser, an author on the team from Erasmus MC.
Perhaps most curious of all was the discovery of very noticeable differences in hair color between the men and women participating in the study.
Based on data gathered by the British biobank and the US genetics company 23andMe, the scientists found that women are 25% more likely to have blonde hair, and less likely to have colored hair. 3 times darker.
While scientists cannot rule out that some of the participants in the study were mistaken about their own hair color, the numbers above are similar to findings from other studies that have Use optical instruments to measure hair color.
In the past, those differences have been attributed to gender preferences, with women thought to prefer dark-haired men and men more preferring blondes.
In addition to helping to understand the biology of human hair color, the study also gives scientists new insights into the genes involved in diseases like skin cancer.
“Pigments are more than cosmetics – they’re important for the immune system and play a role in many diseases. Understanding genetics could lead to new therapeutics,” Spector said.