The shape of the face is determined by fine tuning thousands of genes
Genes sculpt a face
Nadezhda Markina, <url>We recognize a person by face, look for similar features in children and parents, try to remember the appearance of acquaintances after many years.
In other words, a face is the most important identity identifier in everyday life, we don't show fingerprints to each other. Obviously, the face is also individual. Although not everyone is satisfied with his own native face, and people go to plastic surgeons to change the shape of the nose, ears or chin.
Until now, scientists have not yet fully figured out how this individuality is genetically determined, how a face shape unlike anyone else is molded in embryonic development.
Indeed, we differ from each other much more in the shape of the maxillofacial part of the skull than in the shape of the cranium. This issue is closely related to the development of genetic pathologies, congenital deformities, which include, for example, cleft palate, cleft lip, etc.
Scientists from the Lawrence National Laboratory Berkeley investigated the genetic mechanics of the face shape at the level of gene regulation. They analyzed how DNA regulatory sequences work, which molecular biologists call enhancers. They affect the work of genes, often being in a completely different part of the genome. An article in the latest issue of the journal Science (Attanasio et al., Fine Tuning of Craniofacial Morphology by Distant-Acting Enhancers – VM) is devoted to fine tuning the structure of the facial part of the skull, which makes us different from each other.
"Our results show that thousands of enhancers in the human genome are involved in the development of the facial part of the skull and determine the shape of the face," says Axel Wiesel, a geneticist at Berkeley Laboratory, head of the study.
In previous experiments, Wiesel's group mapped regulatory genetic elements that affect the development of the heart, brain, and other organs. Scientists have become convinced that sometimes enhancers can be very far away from their targets, by hundreds and thousands of base pairs.
We are completely different from mice, at least outwardly. Nevertheless, scientists undertook to study the genetics of the face shape again on transgenic mice. They observed the formation of a "mouse face", that is, the maxillofacial part of the skull, during the development of a mouse embryo.
At the same time, the profile of gene activity was analyzed and the role of 4 thousand sequences, which serve as enhancers, affect the development of facial formation genes, was revealed.
Red indicates the activity of regulatory elements affecting the formation of the face as the mouse embryo grows
(drawing from the Berkeley Lab press release What is it About Your Face? – VM).This regulation of multiple genes provides fine tuning.
Enhancers are scattered across the genome, scientists were able to describe in detail the activity of 200 of them. They sequentially removed three of them from the genome and observed the development of facial deformities in mouse embryos, which appear at the same time.
Most of the regulatory enhancer elements found in mice are also present in humans. As scientists have shown, many of them are located on sections of human chromosomes associated with the shape of the face and with congenital deformities.
"Knowledge about the existence of enhancers, which are transmitted from parents to children in the same way as genes, knowledge about exactly where they are located in the human genome, gives us an understanding of how an individual human face is formed," Wiesel says. – Our results also make it possible to search in enhancers for mutations that play a role in the appearance of congenital pathologies. This can be used for genetic diagnosis."
Now Wiesel's group is busy investigating the activity profile of these regulatory elements throughout the genome. In collaboration with human geneticists, they are searching for mutations in these elements that are associated with congenital deformities.
Portal "Eternal youth" http://vechnayamolodost.ru25.10.2013