The brain of man's ancestors was covered with a large number of convolutions thanks to small mutations in two genes that control the "gluing" neurons together; this information is stated by biologists from the Institute of Neurobiology in Munich.
"Imagine two couples of runners; one couple is tightly hold each others hands, while the second only touched each other. In the first case, they will certainly hit the finish line simultaneously under any circumstances, and in the second they can finish with a different time score. "Something similar happens to the brain cortex” - says Daniel Del Toro from the Institute of Neurobiology in Munich, Germany, whose words are cited in the New Scientist journal.
The human cerebral cortex, unlike most other animals, except the whales, monkeys and some other mammals, is covered with large amounts of convolutions. According to scientists, these bands, furrows and folds helped our ancestors learn how to use tools and become intelligent, but the reasons why they appeared and how they were formed remains unknown.
Del Toro and his colleagues started thinking of the changes in the genes functioning that control the formation of the brain that could lead to the appearance of the first simple convolutions in the brain of our ancestors.
Searching for an answer scientists compared the activity of various genes in the cells of the future brain taking human embryos as a basis and mice with a "flat" cortex, and isolated several dozen sections of DNA, the performance of which differed a lot. Then del Toro and his team began to disconnect and incorporate these genes into the DNA of the mice hoping to grow an embryo with a brain that will be covered with convolutions.
The attention of geneticists attracted two genes: FLRT1 and FLRT3, the activity of which was particularly high in the cells of mouse embryos, and very low in the brain of the human embryo. When scientists disconnected both of these genes into the DNA of the mice, they managed to receive mice with brains that had a large number of convolutions.
Why did this happen? The fact is that both these genes are responsible for the same function that lies in density level the neurons are glued together. If their activity is high, then the nerve cells are highly "clinging" to their neighbors, and therefore the surface folds of the cortex cannot be generated at all.
Therefore, when the genes performance is blocked or reducing their activity naturally leads to their appearance; brain stem cells often grow with a different speed thanks to that part of the future cortex will "stick out" itself and other areas will remain on their place.
As Del Toro admits, it is not yet clear whether the mice are cleverer after such a genetic modification or not. Scientists will check whether they have succeeded in deducing "superintelligent" mice in the nearest future, and will also study how FLRT1 and FLRT3 work in the genomes of primates, the brains of which are covered with convolutions.