The formation of the human brain is a mysterious process that takes place in the brain of a newborn baby, with more than 100 billion neurons connected to it. To achieve this amazing biological engineering, the developing embryo’s brain must grow at an average of 250,000 neurons per minute during pregnancy.
These neurons often originate far from where they live and work in the new brain, and although this migration has been extensively investigated in animal models using chemical or biological tracing, it has not been directly studied in humans. until now.
In a new paper, published April 20, 2022 online at NatureScientists at the San Diego University School of Medicine at the University of California, San Francisco, and Radiation Pediatrics, developed new methods for estimating the activity of human brain cells during fetal development by studying recently healthy adults.
Each time a cell splits into two female cells, one or more new mutations occur by chance, and the crumbs can be read by modern DNA sequences.. “
Joseph Gleson, MD, senior author, Radi Professor of Neuroscience, School of Medicine, University of California-San Diego
Gleson is also the director of neuroscience research for genomic medicine at the Rady Pediatric Institute.
“By developing these mechanisms for reading mutations in the brain, we can demonstrate key insights into how the human brain is formed compared to other species.”
Despite 3 billion DNA bases -; And more than 30 trillion cells in the human body -; Gleason and colleagues focused their efforts only on DNA mutations in the first few cell divisions after fertilization or early brain development. By following these mutations throughout the brain, they are able to rebuild the human brain for the first time.
To understand the type of cells that make up these bread crumbs mutations, they developed techniques that differentiated the major cell types in the brain. For example, comparing the neurons that inhibit mutation in neurons, these two types of cells confirm long-standing suspicions that they form in different parts of the brain, and then merge into the cerebral cortex, the outer layer. Organ.
However, they found that mutations in the left and right parts of the brain differed from each other -; At least in humans -; The two cerebral hemispheres differ during development much earlier than previously thought.
According to Martin W. Brews PhD, a former project scientist at UC San Diego and now an assistant professor at UC, it has implications for some diseases, such as epilepsy, epilepsy, and epilepsy. University of Colorado Medical School.
University of California – San Diego
Journal reference dead
Bres, MW, inter alia. (2022) Somatic mosaicism shows the distribution of neocortical development. Nature. doi.org/10.1038/s41586-022-04602-7