How flowering plants survived the asteroid that wiped out the dinosaurs

Sixty-six million years ago, an asteroid the size of Everest struck Earth, causing the extinction of non-avian dinosaurs. Yet, many flowering plants survived that catastrophic event. Researchers from the University of Ghent, in Belgium, published in Cell that these plants endured thanks to a complete duplication of their genome, known as polyploidy.

The team analyzed the genomes of 470 flowering plant species and identified 132 ancient events of whole-genome duplication. They dated these events with the help of 44 fossilized plants, showing they coincided with major environmental crises.

Many of these duplication events did not happen randomly but repeatedly aligned with Earth's most chaotic periods.

Having double the number of genes, which might seem disadvantageous, actually provided resilience during environmental stress. Plants with duplicated genomes showed higher tolerance to heat, drought, and other stresses.

The researchers explained that these duplications occurred at specific times, such as the Cretaceous-Paleogene extinction, oceanic anoxia episodes, and the Paleocene-Eocene Thermal Maximum about 55.8 million years ago.

The PETM is especially relevant because during that period, global temperatures rose between 5 and 8 °C in just 100,000 years, a rate comparable to current climate change. However, scientists warn that today's warming is much faster.

Yves Van de Peer, one of the study's authors, stated that genome duplication can help plants cope with extreme conditions, but the current rapid climate change exceeds historical rates.

The analysis also answered an old biological question: why do modern plant genomes show so few traces of past polyploidy? The answer is that only events occurring during crises managed to become fixed and persist.

Complete data from the study are available on the AngioWGD platform, developed by Ghent University, where researchers can explore the 132 duplication events across the 470 species studied.