IT鈥橲 biological heresy. But each spore of a simple soil fungus turns out to contain more than one genome. In fact, each one may even have thousands of genetic identities.
The fungus, Glomus etunicatum, helps plant roots 鈥渟cavenge鈥� phosphorus from soil and has co-existed with plants around the world for millions of years. Like other related fungi, G. etunicatum reproduces asexually, and while each spore contains up to thousands of individual nuclei, each one was thought to be genetically identical.
Now Ian Sanders and Mohamed Hijri of the University of Lausanne in Switzerland have found this isn鈥檛 so. They have demonstrated that each spore contains at least 12 types of nuclei carrying different genomes, and say it is also possible that every nucleus is genetically unique (Nature, vol 433, p 160).
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Researchers have already shown that the fungus has 13 variants of a particular gene, called PLS1, but until now they believed all these variants co-existed on DNA in a single nuclear genome. Sanders and Hijri have now proved that each nucleus in a fungal spore contains only two at most of the 13 gene variants, so the rest must exist in other nuclear genomes in the same spore.
Carrying multiple genomes within individual spores may help the fungus form partnerships with many plant species, activating whichever genome best suits each host.
