Fungus report stirs debate

A paper suggesting ancient asexual fungi have more than one genome reignites controversy

Charles Choi(cqchoi@nasw.org)
Jan 13, 2005

An ancient group of fungi might possess more than one genome, Swiss researchers report in the January 13 issue of Nature.

Arbuscular mycorrhizal fungi colonize the roots of most land plants. Their cells contain hundreds of nuclei, leading Mohamed Hijri and Ian R. Sanders of the University of Lausanne in Switzerland to suggest multiple genomes could evolve within single individuals.

"These fungi have no sexual reproduction, which means if deleterious mutations accumulated, they might lead to extinction. But these fungi are extremely old, dated at 450 million years," Hijri said. "We think they developed this strategy of multiple genomes against deleterious mutations, such that some genes can get knocked out, but other genomes might have functional versions."

"This means Mendelian genetics and classical evolution cannot apply to these organisms. They are completely unique," Hijri told The Scientist.

The report has reignited a longstanding debate. "I think this data...