Before the first trees sprouted on Earth, the planet’s barren landscape may already have been transformed by fungi, according to new research.
Published in Nature Ecology & Evolution, a new study suggests that fungi emerged on Earth hundreds of millions of years earlier than previously believed. This early diversification may have been responsible for reshaping the environment and the development of future ecosystems.
The study was led by scientists from the Okinawa Institute of Science and Technology in Japan, working with colleagues from the Biological Research Centre in Hungary, the University of Bristol in the UK, and the Barcelona Supercomputing Centre in Spain. These researchers combined cutting-edge genetic techniques with fossil evidence to gain a deeper understanding of the species. Their results provide previously unknown insight into the mysterious origin of the fungal kingdom.
The Enigmatic Fifth Kingdom
Complex multicellularity is relatively rare in the history of the planet. It has occurred independently in just five groups: animals, plants, fungi, red algae, and brown algae. The fossil record offers precise timestamps for most of these lineages, but the origins of fungi have remained relatively unknown.
The bodies of fungi are usually soft and filamentous, and rarely withstand the process of fossilization. Additionally, fungi evolved complex multicellularity several times from diverse single-celled ancestors, making it difficult to trace a single point of origin. As a result, scientists have long debated when fungi first appeared and how their presence may have influenced Earth’s biosphere.
Evolutionary biologists often utilize molecular clocks to estimate how genetic mutations accumulate over time. However, without evidence in the fossil record to calibrate and cross-reference, this method also can’t provide a clear timeline.
The research team, led by Professor Gergely J. Szöllősi, introduced a novel application of the horizontal gene transfer method for determining this timeline. This rare process occurs when genes jump between species rather than being passed down through reproduction. Transfers such as this act like genetic breadcrumbs in time.
“If a gene from lineage A is found inside lineage B, it means the ancestors of A must be older than the descendants of B,” Szöllősi explained. Researchers were able to identify 17 of these transfers across fungi and pinpoint the fungal evolutionary tree with unprecedented precision.
A Billion-Year Head Start
The team’s analysis suggests that the common ancestor of living fungi dates back 900 million to 1.4 billion years. This places their origin long before the first plants on Earth, which only appear in the fossil record around 470 million years ago.
This indicates that fungi may have been among the earliest colonizers of Earth’s barren continents. Co-author Dr. Lénárd L. Szánthó emphasized the significance of this, stating, “Fungi run ecosystems—recycling nutrients, partnering with other organisms, and sometimes causing disease. Pinning down their timeline shows fungi were diversifying long before plants, consistent with early partnerships with algae that likely helped pave the way for terrestrial ecosystems.”
These early fungi may have been responsible for the formation of the first ecosystems by breaking down rock, cycling nutrients, and creating primitive soils. Rather than plants sprouting on sterile land, this research suggests they followed fungi networks that had been altering the planet’s surface for millions of years.
Rewriting Earth’s Timeline
This new timeline reframes the story of biological life on Earth. Instead of plants taking root in a barren landscape, the continents may already have been transformed by fungal activity.
The study also gives weight to controversial claims of billion-year-old fungal fossils discovered in Canada in 2019. While some scientists questioned whether those fossils were truly representative of fungi, the new genetic timeline shows that the existence of fungi during this era would not have been out of place.
Overall, the study showcases how the combination of fossils, molecular clocks, and rare genetic swaps can illuminate chapters of evolutionary history once thought inaccessible.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds a Master of Business Administration and a Bachelor of Science in Business Administration, along with a certification in Data Analytics. His work combines analytical training with a focus on emerging science, aerospace, and astronomical research.