Plants May Have Survived Earth’s Massive Extinctions by Doubling Their Genome

This may be an emergency strategy to survive extinctions.

When the world goes bad, some plants do something astonishing. They can’t run or hide, nor can they do much about changing their ecosystem. Instead, they copy themselves.

We’re not just talking about a gene here or there; we’re talking about whole-genome duplication. A sweeping new analysis of 470 flowering plant genomes suggests that whole-genome duplication can work as an evolutionary gamble. Most of the time, it fizzles out. But during global crises, when life on Earth really is in trouble, these plants seem to have had a survival edge.

A Risky Strategy

Many plants are polyploids, meaning they have more than two sets of chromosomes. In some cases, they make extra copies of their entire genome. It sounds strange, but it’s not a rare strategy.

“Polyploids are all around us,” said Yves Van de Peer, one of the study’s senior authors. “Many of our crops are polyploid and if you go into the field and pick a plant or a flower, there is a 35% chance — some say higher — that you picked a polyploid plant.”

Wheat, cotton, and potatoes are all polyploid. So are some strawberries. However, despite how common this is, it doesn’t seem to be an efficient long-term strategy.

“If we analyze the genomes of different plant lineages, we see very little evidence for whole genome duplications that have survived in the long run,” the researcher told ZME Science.

This strategy doesn’t seem to work long-term — except when things really get dire.

“Whole Genome Duplication is (on the long term, this is important) an evolutionary dead end,” Van de Peer said. “Sometimes they do survive though. But as we show in the paper, only when they occur during times of environmental upheaval or during times of extinction. Only then the advantages of being polyploid outweigh the costs.”

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Doubling Up

The researchers analyzed 470 flowering plant genomes, dating 132 ancient whole-genome duplication events. They found that these duplication events weren’t scattered randomly through time.

Instead, they clustered around some of the most turbulent chapters in Earth’s recent history: the Cretaceous-Paleogene extinction (the dinosaur extinction), the Paleocene-Eocene Thermal Maximum (when the Earth Was scorching), or the Eocene-Oligocene Transition (another major extinction).

The finding offers a new way to think about polyploidy. Most of the time, doubling a genome may be a burden. But during environmental upheaval, it may become a lifeline.

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Duplicating your genome can cause trouble. Cells may grow differently and your reproduction can be affected. Polyploids may have reduced fertility, and the genome itself may be thrown into turmoil. But during upheaval, the situation changes. A doubled genome gives evolution more raw material to work with. Extra gene copies can act like backups, making plants more tolerant of harmful mutations and sudden shocks such as drought, cold, heat, salt, darkness, or disrupted ecosystems. Some duplicated genes can keep doing their old jobs while others evolve new or stronger stress-response roles.

“Well, it is important to realise that WGD is a continuous process that occurs all the time. But when it coincides with periods of environmental upheaval, they can make the difference and the polyploids can outcompete the ‘diploids’,” Van de Peer told ZME Science.

The study is cautious. It doesn’t claim to have nailed the mechanism, but it presents a very plausible hypothesis, that seems to fit the data.

Did Genome Duplication Help Plants Survive the Dinosaur Extinction?

Whole genome duplication mainly occurs in plants, but it can happen in animals as well, for instance in insects, spiders, amphibia, and fishes. There even have been two ancient WGDs in the vertebrate ancestor, says Van de Peer. “If you analyse the genome of vertebrates, including humans, you see the remnants of WGDs about 500 mya.”

But mammals and birds (and birds are living dinosaurs) don’t seem to tolerate this kind of genome doubling in the same way plants do. Van de Peer’s likely explanation is sex chromosomes. Doubling sex-chromosome systems can disrupt development so severely that the result is non-viable.

We asked Van de Peer if genome duplication helped plants survive the cataclysm unleashed by the asteroid that brought the demise of the asteroid.

“Hard to say,” the researcher noted. “But WGD has been shown to increase stress resilience. Having extra genes leads to mutational robustness.”

Then he offered a vivid possibility. After the asteroid impact, dust and aerosols may have dimmed sunlight. Photosynthesis became harder, and in that dim world, a plant with altered physiology might have had an edge.

“Polyploid plants might be better at photosynthesis,” Van de Peer said. “So during the aftermath of the meteor impact, one can imagine that a polyploid would still be able to capture the little light, while the diploids can’t.”

Climate Hopes

The study’s might also have an important lesson for today.

If ancient polyploids were more likely to establish during climate shocks, then today’s climate crisis may once again tilt evolution toward genome-doubled organisms. The authors explicitly connect their findings to contemporary climate change and rapid global warming.

Van de Peer goes further: nature may select more polyploids over non-polyploids because that is what it appears to have done before. The authors call polyploids “hopeful monsters,” borrowing an old evolutionary phrase for organisms that look maladapted under normal conditions but may thrive when conditions change.

“During challenging environmental times, polyploids seem to have higher chances of survival,” the researcher concludes.

Journal Reference: Cell, Chen et al., “The rise of polyploids during environmental upheaval” https://www.cell.com/cell/fulltext/S0092-8674(26)00397-1