New research explores the complexities of the DNA behind what makes a person's face just as unique as their fingerprint, according to a news release.
The study comes from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley's Lab). The researchers said genetic enhancers are involved to make children look like their parents, while still having their own individual face. The research also delved into why siblings can look identical to each other, especially twins, but not with unrelated people.
"Our results suggest it is likely there are thousands of enhancers in the human genome that are somehow involved in craniofacial development," said co-author Axel Visel, a geneticist with Berkeley Lab's Genomics Division. "We don't know yet what all of these enhancers do, but we do know that they are out there and they are important for craniofacial development."
Published in the journal Science, Visel and his colleagues studied craniofacial development, such as defects like clefts, in transgenic mice. This research team has previously studied genetic enhancers in the heart, brain and other organ systems.
"We used a combination of epigenomic profiling, in vivocharacterization of candidate enhancer sequences, and targeted deletion experiments to examine the role of distant-acting enhancers in the craniofacial development of our mice," said lead author Catia Attanasio. "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."
The rearchers identified more than 4,000 genetic enhancer sequences that actively upgrade the processes involved in craniofacial development. Although the study was conducted on mice, many sequences are likely present in humans as well. The researchers said they are located in human chromosomes and contribute to the forming of a face and to defects as well.
"Knowing about the existence of these enhancers, which are inherited from parents to their children just like genes, knowing their exact location in the human genome, and knowing their general activity pattern in craniofacial development should facilitate a better understanding of the connection between genetics and human craniofacial morphology," Visel said. "Our results also offer an opportunity for human geneticists to look for mutations specifically in enhancers that may play a role in birth defects, which in turn may help to develop better diagnostic and therapeutic approaches."
