The search for scientists at the University of California San Diego School of Medicine has shed new light on a secular question: what makes the human brain unique?
The discovery of the team comes from their investigation into the regions accelerated by man (HARS) – of the sections of the human genome which have accumulated an unusually high level of mutations as humans have evolved. There is a lot of scientific interest in the Hars, because they are supposed to play an essential role in the Conference of Rales specific to humans, and also have links with neurodevelopmental disorders, such as autism.
One of the reasons why scientists think that Hars conferred human -specific features is that they have undergone rapid changes in their genetic sequences since we separated from our nearest relative – Chimpanzee – about 5 million years ago.
Now, researchers from UC San Diego have identified a har123 in Har123 in particular – which seems to help shape the human brain.
The researchers discovered:
- Har123 himself is not a gene, but is rather a type of molecular “volume control” known as a transcriptional amplifier. Transcriptional amplifiers control which genes are activated, how activated they are and at what times they are activated during the development of an organism.
- Thanks to its role as a transcriptional activator, HAR123 promotes the development of neural progenitor cells, cells that give birth to the two main types of brain cells – neurons and glial cells.
- Har123 also influences the relationship of neurons and glial cells which are formed from neural progenitor cells.
In the end, Har123 promotes a particularly advanced human trait called cognitive flexibility, or the ability to unlearn and replace previous knowledge.
In addition to providing new information on human brain biology, the results also offer a molecular explanation for some of the radical changes that have occurred in the human brain during our evolution. This is argued, for example, by the observation of the authors that the human version of Har123 has different molecular and cellular effects that the chimpanzee version in stem cells and precursor cells of neurons in a petri box.
Additional research is necessary to better understand the molecular action of Har123 and if the human version of Har123 indeed gives human -specific neural traits. This research line could lead us to a better understanding of the molecular mechanisms underlying many neurodevelopmental disorders, such as autism.
The study, published online in Scientific advanceswas led by Miles Wilkinson, Ph.D., distinguished professor, and Kun Tan, Ph.D., assistant professor, both within the department of obstetrics, gynecology and reproductive sciences at UC San Diego School of Medicine. Wilkinson is also a faculty of affiliation of the UC San Diego Institute for genomic medicine. The study was funded, in part, by subsidies from the National Institutes of Health and 10x Genomics.
