More than 600 species of unclassifiable fungi have a common origin, study finds

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Over 600 species of unclassifiable fungi have a common origin, study finds

As part of their study, the researchers studied about thirty species, including this fungus of the genus Geoglossum.

Researchers at the University of Alberta have sequenced the genomes of about 30 unclassifiable species of fungi, and have come to the conclusion that more than 600 species have a common ancestor that would have existed 300 million years ago. years.

Most of these species shared no visible common characteristics. It was during the study of their genomes that this common origin was revealed.

The fungi studied are part of the large phylum Ascomycetes, which includes truffles, molds, penicillin, baker's yeast, and what gives you athlete's foot. […] It is therefore a hyper-diverse group, lists the doctoral student at the University of Alberta David Díaz Escandón, who participated in the study.

We knew several unclassifiable [fungi] in this group that we wanted to place in the history of the evolution of [ascomycetes], he explains.

Of the 30 species studied, 22 share a genetic origin. The detailed study of their genomes has made it possible to extrapolate the common origin of more than 600 species of fungi.

We show that 22 of these lineages, collectively representing more than 600 species, trace back to a single origin that diverged from the common ancestor of Eurotiomycetes and Lecanoromycetes, more than 300 million years BCE, says the study published in the journal Current Biology.

Louis Bernier, professor of mycology and forest pathology at Laval University, who did not not participated in the study, popularizes the conclusions of the researchers.

They demonstrate that several species of fungi which, at first glance, do not have much in common, and indeed from a genetic point of view are in fact very common, very similar. The simplest hypothesis, at this point, is that they all derive from the same common ancestor.

This common origin therefore dates back to a period that precedes the appearance of dinosaurs on Earth, when the land masses were gathered on the megacontinent of Pangea.

The study has uncovered the genetic origin of the lichen Candelina mexicana.

For David Díaz Escandón, this new discovery adds a piece to the puzzle of the evolution of fungi.

To be able to know the age of these species, scientists rely on the transformation of their DNA over the course of evolution. If you don't have the complete history, their complete evolution, their transition, you will have the wrong estimates of their age. Filling the gap in scientific knowledge allows us to answer many questions with more certainty, says David Díaz Escandón.

He explains that he and his colleagues first targeted species whose genome was unknown. They then compared this new data to genetic sequences included in international databases, and found that several species had been assigned to the wrong groups.

“It changed their taxonomic classification, because that has always been tied to their appearance, but by adding molecular data, we can track their evolutionary history. »

— David Díaz Escandón, PhD student in the Department of Biological Sciences at the University of Alberta

According to Louis Bernier, this discovery would not have been possible without the accessibility of the genetic sequencing. In the world of mycology, this is a revolution that we have been experiencing for 10 to 15 years. Now, we can sequence whole genomes, at ridiculously low prices. So it allows for much more powerful studies than before. […] It brings about an upheaval in our taxonomic and phylogenetic classifications, he explains.

Professor Bernier is confident about the future of his discipline: We don't know still not how many species of mushrooms there are in the world. It is thought that there would be, depending on the authors, from 2 to 5 million species. So far, about 150,000 species of fungi have been described.

There is a lot of work for future taxonomists in mycology, he concludes.< /p>

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