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An evolutionary leap without rules: The environments colonized by plants with a doubled genome

Research conducted by Filip Kolář of the Faculty of Science, Charles University, and Patrick Meirmans of the University of Amsterdam has revealed that genome duplication (polyploidization)—a process playing a key role in plant evolution and breeding—has a significant but inconsistent impact on the ecological requirements of individual species.

The results have been in Proceedings of the National Academy of Sciences.

The study, which analyzed more than 25,000 geographically localized records of the occurrence of different ploidy levels across 129 species of flowering plants, shows that changes in chromosome set number often lead to changes in climatic niche—that is, the conditions in which plants occur. Surprisingly, however, no consistent direction in these changes was found.

"In general, the main finding is that genome duplication in plants—which is probably the most extensive type of DNA mutation known in plants or animals and a process important in both agriculture and the conservation of natural genetic diversity—affects where plants grow. This is what we show through a large meta-analysis of published data," says Kolář from the Department of Botany at the Faculty of Science, Charles University.

"But the specific direction of the effect is not easy to predict—each species behaves somewhat differently. So we cannot say, contrary to what has long been assumed, that after genome duplication, plants always colonize mountain environments or drier areas. It's actually a publication of a negative result, which is itself fairly unusual in science."

"The work is a meta-analysis of published field data gathered by dozens of teams worldwide, and it clearly illustrates the importance of even partial case studies and the benefit of the open science approach, which is increasingly promoted in today's global science. We are also grateful to the many researchers who facilitated our access to their data," Kolář adds.

While 74% of the species showed a significant difference in climatic niche between different ploidy levels, no specific climatic factor (e.g., temperature, precipitation, or altitude) was found to consistently explain these differences across all species. The assumption that polyploids generally have broader ecological tolerance and wider distribution ranges was also not confirmed.

The results highlight the importance of considering ploidy variation in ecological studies and may impact biodiversity research as well as predictions of climate change effects on species distributions.