Study reveals how some species survived mass extinction

Geneticists have made a significant discovery about the sturgeon and paddlefish's prehistoric past that has important ramifications for our understanding of evolution.

They discovered a previously unrecognised instance of "whole genome duplication" (WGD) in the shared ancestor of these species, an occurrence that seems to have encouraged genetic variations that may have given some species an advantage during a severe mass extinction event around 200 million years ago.

The overall discovery raises the possibility of numerous undiscovered shared WGDs in other species that predate periods of extreme environmental upheaval throughout Earth's turbulent history.

The discovery was made in the research which was published in the journal Nature Communications and led by Professor Aoife McLysaght and Dr Anthony Redmond from Trinity College Dublin’s School of Genetics and Microbiology

According to Professor Aoife McLysaght, whole genome duplication is an evolutionary event where a species has twice the genetic material as it did before, providing a lot of raw material for mutations and evolution.

This process, known as rediploidisation, occurs after a species' genome has been copied and pasted, resulting in a four-copy genome. The time it takes for the second part of the process to complete is crucial, as some gene duplications appear species-specific after the two species are separated on the tree of life, he explained.

This process may have contributed to the ancient original whole genome duplication that occurred before the species separated, potentially generating genomic conditions that helped species survive mass extinctions.

"Similarly, sturgeons and paddlefish show evidence of shared and non-shared gene duplications derived from the ancient whole genome duplication, which occurred just before the Permian-Triassic mass extinction, which wiped out over half of the families of all living things," Professor McLysaght said.

Such developments may help prove that WGD events provide species with a larger evolutionary canvas, increasing genetic material capacity for variations and potentially conferring advantages in coping with changing environmental conditions.

This was evident during the rediploidisation period, which coincided with the Triassic-Jurassic mass extinction around 200 million years ago, SciTech Daily reported.

Meanwhile, Dr Anthony Redmond's findings reveal multiple genome duplication events in early vertebrate ancestors that have shaped the modern human genome and sturgeon and paddlefish genome evolution.

“Our findings are exciting because, as well as shining a light on sturgeon and paddlefish genome evolution, they provide a comparative snapshot of how our early vertebrate ancestors’ genome and duplicated genes evolved after these doubling events," he said.