How Are Genetic Mutations Linked To Biological Evolution? New Study Gives Answers

The first-of-its-kind study shows that different combinations of genetic mutations can have an impact on the evolutionary process. The finding that could benefit areas such as personalised medicine.

New Delhi: Survival of the fittest is one of the most important aspects of biological evolution. The theory of the survival of the fittest states that organisms that develop genetic traits which allow them to better adapt to their physical environment are more likely to thrive, and thus pass down their winning genes to their offspring. 

The process of natural selection results in genetic differences that give some organisms an edge over others, from the longer-beaked Galapagos Island finches studied by biologist Charles Darwin that enabled them to more effectively snatch insects, to the ability of some humans over others to digest milk. Natural selection is a mechanism of evolution in which organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success, causing species to change and diverge over time. 

The study, led by researchers from University of Toronto Mississauga, was recently published in the journal Science. The new research adds an important dimension to our understanding of how genes interact in the evolutionary process.

Why Is The Study Special? 

It is a first-of-its-kind study which shows that different combinations of genetic mutations can have an impact on the evolutionary process. This is a finding that could benefit areas such as personalised medicine and design. 

In a statement released by University of Toronto Mississauga, Alex N. Nguyen Ba, the co-principal investigator behind the study, said evolution is a force that drives all of life on this planet, and that understanding how much we can predict about adaptation has been of strong interest to many people in the field.

According to the study, adaptation can be compared to climbing a mountain. Successive mutations can be compared to the paths taken to the various possible peaks, and specific combinations of mutations acquired along the way can be considered to be the irregularities in the terrain. 

How Can Scientists Predict The Route To The Mountain Top?

Nguyen Ba said there are huge implications if one can figure out what is going to happen in the future for living organisms. 

At the University of Toronto Mississauga, Nguyen Ba and his team of researchers explore genetic mutations in cells and their impact on evolution using next-generation technologies, which include high-throughput synthetic biology, and a desk-sized robot that can process numerous biological samples. High-throughput synthetic biology is used in designing new biological systems or changing existing ones for research purposes.

Researchers Used CRISPR Gene-Editing To Alter Genes In Yeast Cells

Nguyen Ba and Christophe Bakerlee, who is the study's co-principal investigator, used CRISPR (Clustered regularly interspaced short palindromic repeats) gene-editing technology to alter genes in the cells of yeast, which is commonly used in genetic engineering research because it shares some genes with humans, the study said. CRISPR is the hallmark of a bacterial defence system that forms the basis for CRISPR-Cas9 genome editing technology. CRISPR is a highly precise gene-editing tool and is a way of finding a specific bit of DNA inside a cell.

The Team Worked With 10 Missense Mutations

The researchers worked with 10 missense mutations, which are alterations in DNA code that change the production of amino acids, the building blocks of life. Amino acids combine to form proteins, which heal wounds, provide energy, and make antibodies in the body of an organism. 

What Are Combinations Of Gene Mutations With Negative Synergy?

The scientists tested a total of 1,024 combinations of mutations, in order to determine how interactions between genes affect expression of certain genetic traits. The new study revealed that evolution frequently samples combinations of gene mutations with negative synergy between them, which acts on the yeast's evolutionary potential in negative ways. For instance, sampling of combinations of gene mutations with negative synergy between them slows their rate of adaptation.

Combinations Of Mutations Dictate Evolutionary Potential Of Organism

The findings of the research run counter to the dogma that all biological adaptation unfolds in a predictable way, according to the study. Instead of biological adaptation unfolding in a predictable way, combinations of mutations that have accumulated through time dictate the future evolutionary potential of an organism.

According to Nguyen Ba, this challenges the dominant view in genetic research that one should study one gene mutation at a time. By examining mutations in combination, we can understand diseases better, and develop more precise medicine.

Nguyen Ba said the researchers are showing that in order for us to have a full understanding of how genes actually behave, the combinations of mutations are likely to be very important.