Detecting the 'secret' of hair

Forensic scientists are taking a step closer to predicting the color of a suspect's hair just from his DNA, after discovering more than 100 new genes that affect a person's hair color.

A new genetic-based test has yielded 10-20% more accuracy than the currently used forensic tests, and is very reliable for dark hair or black hair. And brown hair and blond hair are harder to predict, researchers said.

"If someone leaves blood at a crime scene, then from that person's DNA, you can say they have black or hung hair with about 90% certainty , " said Tim Spector, the lead author of the project. Research at King's University in London, said.

A person's hair color is one of the most genetic characteristics in their appearance, with studies of twins showing that genetics affects up to 97% of hair color. Until now, scientists have only known about 13 types of genes that affect the brightness in a person's hair color.

After studying DNA of nearly 300,000 people, researchers from King's University and Erasmus University Medical Center (Erasmus MC) in Rotterdam discovered 124 genes that contribute to hair color, or directly. affect the production and distribution of natural melanin or through other biological mechanisms, many of which are still not well understood.

A person's hair color may reveal many things - (Photo: Pinterest).

According to a recent study reported in the journal Nature Genetics, a large number of newly discovered hair color genes help explain 35% of hair growth, 25% blonde and 26% black hair.

It is possible that hundreds of other genes also affect hair color in ways that are too small for scientists to detect.

One factor that makes hair color forensic testing complicated is the tendency that is common in babies born with blond hair but then turned brown a few years later. Although the change itself may have been caused by the gene, the researchers did not detect which gene caused it.

"We know that some blond children are turned into brown hair, but don't know why," said Manfred Kayser, an author in the research group from Erasmus MC.

Perhaps more intriguing is the discovery of very visible differences in hair color between men and women participating in the study.

Based on data gathered by the UK biological bank and the 23andMe genetics company, scientists found that women were 25% more likely to have blond hair, and less likely to have colored hair. 3 times darker.

Although scientists cannot rule out the case that some participants in the study were confused about their own hair color, the above figures are similar to findings from other studies. Use optical instruments to measure hair color.

In the past, these differences were thought to be due to gender-related interests, when women were said to prefer darker men and men prefer blondes.

In addition to helping to understand the biology of human hair color, the study also gives scientists new insights into the types of genes involved in diseases like skin cancer.

"Pigments are more than cosmetics - they are important for the immune system and have a role in many diseases. Understanding genetics can lead to new treatments , " Spector said.