Scientists from the EPFL and the University of Geneva have discovered a genetic mechanism that defines the shape of our members in which, surprisingly, genes play only a secondary role. The research published in Cell, online the 23rd of November, shows the mechanism is found in a DNA sequence that was thought, incorrectly, to play no role.
Turbos on the genome
DNA is composed of only about 2% genes. But it has other types of sequences, such as enhancers that increase the activity of certain genes at key moments. "The discovery we have made is that the group of genes involved in finger growth is modulated by seven enhancers, not just one, and they combine through contact," says Thomas Montavon, lead author of the article and researcher at the EPFL.
When the fingers in the embryo begin to take shape, the string of DNA folds and the enhancers, located on different parts of the string, come into contact. They then bring together various proteins that stimulate the activity of the genes, and the fingers start to grow. If one of these seven enhancers is missing, the fingers will be shorter, or abnormally shaped. When two are missing, the defects are even more pronounced. Without enhancers, the genes work slowly, and generate only the beginnings of fingers.How does the DNA fold in exactly the right way so that the enhancers will correctly do their job? The recently discovered process remains largely unexplained. "In other tissues, such as the brain, the string of DNA folds differently," says Denis Duboule, director of the study and researcher at both the EPFL and the University of Geneva. "To our knowledge, it is only in the fingers that it adopts this shape."
An explanation for evolutionary diversity
Statistically, the seven enhancers involved in finger growth create seven opportunities for a mutation to occur. The flexibility of this mechanism, with no known equivalent to date, causes not only hereditary malformations, but also the many variations in the hands, legs and other appendages in nature. "Just think of some ungulates, which walk on a single finger, or the ostrich, which has only two, and the human hand, of course" explains Denis Duboule.
Other genetic processes may also function on the basis of a similar principle. This could explain the diversity of the products of evolution, in areas other than the fingers, according to Denis Duboule. "When a mutation occurs on a gene, for instance in cystic fibrosis, it is often binary. This amounts to an 'all or nothing' situation. With the mechanism we have discovered, it is a 'more or less' situation. It is combined, it is modulated."
This research is carried out within the National Center of Competence in Research (NCCR) Frontiers in Genetics. The NCCRs are an initiative of the Swiss government to stimulate research and education in key areas. http://www.frontiers-in-genetics.org
Vidéo (interview with Denis Duboule) : http://www.youtube.com/watch?v=jrFG34HPqN8
Denis Duboule firstname.lastname@example.org or 41-21-693-83-38
Thomas Montavon email@example.com or 41-21-693-06-05Lionel Pousaz, EPFL Media & Communications, firstname.lastname@example.org
Lionel Pousaz | EurekAlert!
Nonstop Tranport of Cargo in Nanomachines
20.11.2018 | Max-Planck-Institut für molekulare Zellbiologie und Genetik
Researchers find social cultures in chimpanzees
20.11.2018 | Universität Leipzig
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
21.11.2018 | Power and Electrical Engineering
20.11.2018 | Life Sciences
20.11.2018 | Life Sciences