When it comes to determining a person's eye, hair and skin color based on a DNA sample, scientists typically need to compare that evidence sample to an existing reference sample. That's reportedly no longer the case, however, if they're using the new HIrisPlex-S DNA test system.

HIrisPlex-S was developed by scientists from Indiana University - Purdue University Indianapolis School of Science (IUPUI), working with colleagues at Erasmus MC University Medical Center Rotterdam in the Netherlands. It's a web tool that utilizes a prediction model, which was trained on the DNA of thousands of individuals.

"We have previously provided law enforcement and anthropologists with DNA tools for eye color and for combined eye and hair color, but skin color has been more difficult," says IUPUI forensic geneticist Susan Walsh, who co-directed the study. "Importantly, we are directly predicting actual skin color divided into five subtypes – very pale, pale, intermediate, dark and dark to black – using DNA markers from the genes that determine an individual's skin coloration. This is not the same as identifying genetic ancestry. You might say it's more similar to specifying a paint color in a hardware store rather than denoting race or ethnicity."

The technology is now freely available online, for all investigators who wish to use it.

"With our new HIrisPlex-S system, for the first time, forensic geneticists and genetic anthropologists are able to simultaneously generate eye, hair and skin color information from a DNA sample, including DNA of the low quality and quantity often found in forensic casework and anthropological studies," says Manfred Kayser of Erasmus MC, co-leader of the study.

A paper on the research was recently published in the journal Forensic Science International: Genetics.

Source: IUPUI