Junk DNA Determines Facial Features

There are over seven billion people in the world but no two faces look the same (excluding identical twins, of course). What makes our face so unique? A new study has found that junk DNA affects how we look.

The study was conducted by researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). They found that gene enhancers or DNA sequences that modify the function of other genes play an important role in the development of facial features. These short DNA sequences are present in the non-coding or junk region of the genome.

Many studies have been conducted on understanding facial abnormalities such as cleft palate but not many focus on how normal faces develop.

The idea of junk DNA affecting facial features isn't new. Previous research by Stanford University researcher Joanna Wysocka and her colleagues had found that non-coding DNA can influence facial development.

For the present study, researchers used a technique called optical projection tomography, which allowed them to create a 3D model of a developing mice embryo, New Scientist reported. The technique helped them identify key genes during a biological process. They found that certain genetic enhancers were highly active during craniofacial development.

To further analyze the effects of enhancers, the scientists created mouse models that lacked one enhancer. They found that each enhancer affected a certain facial feature. For example, mice lacking a certain DNA sequence had a longer face while another set had a relatively larger head.

"We used a combination of epigenomic profiling, in vivo characterization of candidate enhancer sequences, and targeted deletion experiments to examine the role of distant-acting enhancers in the craniofacial development of our mice," said Catia Attanasio, the lead author of the study.

"This enabled us to identify complex regulatory landscapes, consisting of enhancers that drive spatially complex developmental expression patterns. Analysis of mouse lines in which individual craniofacial enhancers had been deleted revealed significant alterations of craniofacial shape, demonstrating the functional importance of enhancers in defining face and skull morphology," Attanasio added in a news release.

Researchers even identified over 4,000 enhancers that tuned the activity of genes regulating face development. They analyzed the location of all these enhancers and developed genome-wide maps.

The team is now working with genecists to identify the genes that regulate face formation in humans.

The study is published in the journal Science.