Mug shots from DNA possible, say scientists
DNA can already tell us the sex and ancestry of unknown individuals, but now an international team of researchers is beginning to connect genetics with facial features, degrees of femininity, and racial characteristics.
Writing about their work in PLOS Genetics, the researchers detail how by jointly modeling sex, genomic ancestry, and genotype, the independent effects of particular genes on facial features can be extracted. "By simultaneously modeling facial shape variation as a function of sex and genomic ancestry along with genetic markers in craniofacial candidate genes, the effects of sex and ancestry can be removed from the model thereby providing the ability to extract the effects of individual genes," explained researcher Mark D. Shriver, from Penn State.
The researchers looked at both actual physical face shape and genetic markers of face shape. For physical face shape, the researchers used populations of mixed West African and European ancestry from the U.S., Brazil and Cape Verde. They placed a grid on 3-D images of the faces of the subjects and measured the spatial coordinates of the grid points. They then used statistical methods to determine the relationship between the variation in the faces and the effects of sex, genomic ancestry and genes that affect the shape of the head and face.
To identify these genes, the researchers looked at known genetic mutations that cause facial and cranial deformation because these genes in their normal variations might also affect the face and head. For example, one gene affects the lips, another changes the shape and configuration of the bones around the eyes, and another influences the shape of the mid face and skull.
Eventually, the researchers think that they might approximate the image of a parent from the DNA of children or better visualize some of Homo sapiens' ancestors by examining DNA. On a more practical level, they suggest that law enforcement groups might soon be able to create a mug shot from DNA to identify both victims and criminals. "Currently we can't go from DNA to a face or from a face to DNA, but it should be possible," said Shriver.