The scientists at the Max Planck Institute of Molecular Cell Biology and Genetics seem to have mimicked the evolutionary incident of the deviation of humans from other primates, with their latest study.
Accordingly, marmosets with larger brains have been grown by inserting into them a gene unique to humans. Based on their report, they expressed the gene named ARHGAP11B in 101-day old marmoset fetuses. This gene is responsible for creating an enlarged neocortex which is a part of the cerebral cortex that facilitates advanced cognitive abilities, such as reasoning and language, and is distinctively larger in humans compared to other primates.
In the process of brain enlargement, the gene triggers brain stem cells to form more stem cells. In addition to that, the brain surface has been found to be folded and the cortical plate thicker than normal, according to Michael Heide, the lead study author of the research.
Further, increased numbers of basal radial glia progenitors in the outer subventricular zone and increased numbers of upper-layer neurons which are a sign of primate evolution had been observed.
A notable feature regarding the study is that this is the first time this brain enlarging effect has been expressed by the gene in a non – human primate.
It has been found earlier, that this turning point in the evolutionary history of our lineage had taken place about 1.5 million to 500,000 years ago, with the point mutation (in this case, a substitution) of a single letter, namely C to G, which had correspondingly led to the loss of 55 nucleotides in the formation of the messenger RNA. This eventually had caused a shift in the reading frame, which led to this sequence of 47 amino acids in the protein, as explained by Wieland Huttner.
However, during this research, the team had stopped at the fetal phase of the monkeys to confine to ethical boundaries.