Another way to deal with distinguish genomic areas in our cerebrum that add to make us human

Overview

• Post By : Kumar Jeetendra


• Source: Swiss Institute of Bioinformatics


• Date: 17 Dec,2020

With just 1% gap, the human and chimpanzee protein-coding genomes are remarkably similar. Knowing the biological characteristics that make us human is a part of a fascinating and intensely debated line of study. The paper is printed in Science Advances.

Gene expression, not gene arrangement
To describe what sets human besides their ape relatives, researchers have hypothesized that it’s not too much the DNA sequence, but instead the regulation of these genes (i.e. when, where and how strongly the gene is expressed), which plays the crucial role. But precisely pinpointing the regulatory components which behave as’gene dimmers’ and are positively selected is a challenging task that has thus far conquered researchers (see box).

To be able to answer such tantalizing questions, one has to be able identify the parts in the genome that have been under so called ‘positive’ selection [see box]. The answer is of great interest in addressing evolutionary questions, but also, ultimately, could help biomedical research as it offers a mechanistic view of how genes function.”

Marc Robinson-Rechavi, Group Leader at SIB and Study Co-Author

Researchers in SIB and the University of Lausanne have developed a new method that has allowed them to identify a large set of gene regulatory regions in the mind, chosen throughout human evolution. Jialin Liu, Postdoctoral researcher and lead author of the study explains:”We show for the first time that the human mind has undergone a particularly high degree of positive selection, in comparison with the gut or heart for example. This is exciting, because we now have a means to identify genomic regions which may have contributed to the development of our cognitive skills!”

To reach their conclusions, both researchers combined machine learning models using experimental data on how ardently proteins involved in gene regulation pertain to their own regulatory sequences in various tissues, and then conducted evolutionary comparisons between human, chimpanzee and gorilla. And the more we learn about the genes they’re controlling, the more complete our knowledge of cognition and development, and the more scope there’ll be to act on that understanding,” concludes Marc Robinson-Rechavi.

Box – Positive selection: a sign of the operational value of a mutation
By comparison, an acceleration at that speed in a specific portion of the genome can reflect a positive choice for a mutation that helps an organism to survive and reproduce, making the mutation more likely to be passed on to future generations. Gene regulatory elements are often just a few nucleotides long, which makes estimating their stride rate especially difficult from a statistical viewpoint.