The study of the most ancient living vertebrates - lampreys - made it possible to find out that humans received a brain thanks to the Anf / Hesx1 gene, which is close to its "brother" - Xanf.
The Scientific Reports journal presents the conclusions of researchers from the Institute of Bioorganic Chemistry of the Russian Academy of Sciences. The focus of geneticists was on lamprey DNA. The latter are primitive jawless fish, the length of which can vary from 10 to 100 cm. The interest in lampreys was caused by the fact that they are the most ancient living vertebrates. This feature helped scientists to figure out the secret of the appearance of the brain in humans.
Previously, researchers have already paid attention to the Xanf gene: it is responsible for the growth of the front of the frog embryo. It is thanks to Xanf that the brain is formed in the animal. Scientists have suggested that this gene (or rather, one of its "modifications") may be responsible for the growth of the brain and skull in such ancient vertebrates as lampreys. It was not possible to prove this for a long time, but now the researchers have received convincing evidence in favor of their hypothesis. The embryos of Lethenteron camtschaticum lampreys were grown, after which the specialists extracted RNA molecules from their heads, which are produced by cells during the "reading" of genes. Then many short strands of DNA were collected.
The study of DNA sequences made it possible to understand the mechanism of brain formation in lampreys. It turned out that the analogue of the Xanf gene, Anf / Hesx1, is responsible for this. Compared to more complex vertebrates, the "brain" gene in lampreys is activated at a later stage in the development of the creature. That is why lampreys have such a small brain.
Scientists believe that the Anf / Hesx1 gene appeared about 550 million years ago and played one of the most important roles in the evolution of vertebrates. It was thanks to him, according to the presented conclusions, that the person received the brain in its current form.
Earlier, we recall, another group of specialists revealed the fundamental unity of the structure of the brain in different invertebrates. According to experts, this indicates that these animals have a single ancestor who lived on the planet about 600 million years ago.