Fifteen genes that determine our facial features have been identified in a genome-wide mapping study. The findings have implications for facial genetics studies, according to the international team whose research was published yesterday in Nature Genetics.
The 15 replicated loci will help researchers figure out which genes in our DNA are responsible for specific characteristics of our face. "We're basically looking for needles in a haystack," says Seth Weinberg of the University Pittsburgh. "In the past, scientists selected specific features, including the distance between the eyes or the width of the mouth. They would then look for a connection between this feature and many genes. This has already led to the identification of a number of genes but, of course, the results are limited because only a small set of features are selected and tested."
In a new study, the researchers adopted a different approach. "Our search doesn't focus on specific traits," lead author Peter Claes of KU Leuven, explains. "My colleagues … each provided a database with 3D images of faces and the corresponding DNA of these people. Each face was automatically subdivided into smaller modules. Next, we examined whether any locations in the DNA matched these modules. This modular division technique made it possible for the first time to check for an unprecedented number of facial features."
The scientists were able to identify fifteen locations in our DNA. They found out that genomic loci linked to these modular facial features are active when our face develops in the womb. "Furthermore, we also discovered that different genetic variants identified in the study are associated with regions of the genome that influence when, where and how much genes are expressed," says Joanna Wysocka of the University Stanford.
Seven of the fifteen identified genes are linked to the nose, and that's good news, Peter Claes continues. "A skull doesn't contain any traces of the nose, which only consists of soft tissue and cartilage. Therefore, when forensic scientists want to reconstruct a face on the basis of a skull, the nose is the main obstacle. If the skull also yields DNA, it would become much easier in the future to determine the shape of the nose."