With the help of a unique human gene associated with the evolution of neocortex, Japanese and German scientists were able to increase the brain volume of the embryos of a monkey.
The ARHGAP11B gene is only present in humans and is associated with brain cell growth. It is believed that this gene appeared about five million years ago, after the separation of the evolutionary line that led to the emergence of Neanderthals, Denisovans, and modern humans.
In previous studies, scientists have already found that ARHGAP11B mice cause increased growth of non-correx, but the impact of the gene on primates has not yet been studied. Scientists from the Japanese Central Institute for Experimental Animals, Keio University in Tokyo, and the Institute of Molecular Cell Biology and Genetics of the Planck Mask Society in Leipzig have decided to fill this gap.
The Japanese participants in the study are pioneers in the development of transgenic primate production technologies, and their experience has been used to modify the genes of an ordinary player (Callithrix jacchus), a small monkey living in the forests of Brazil. During the experiment, the embryos of these animals were provided with human ARHGAP11B expression during the development of the neocortex. After 100 days of development and 50 days before the normal date of birth, the brain of the embryos was thoroughly studied at the Institute for Molecular Cell Biology and Genetics in Leipzig.
“We found that the neocortex of players was enlarged and the brain surface was covered with folds. The cortical plate was also larger than normal,” says Michael Heide, one of the authors of the study. – In addition, we found an increased number of precursor cells, namely basal radial gliocytes, in the external subventricular zone, as well as an increased number of neurons in the upper cortex. The increase in the number of these neurons is typical for the evolution of primates”.
From the obtained results, scientists concluded that it was the ARHGAP11B gene that determined the development of human neocortex during the evolution. At the same time, they note that in the course of their study, consciously limited the study of the brain of embryos, considering it ethical – given the impact of the gene on brain development, the consequences after the birth of these monkeys could be completely unpredictable.