This is scientific American 60 second science.

I'm Christopher and Tagyatta.

Likens.

They're probably the most common example of two organisms living in a symbiotic relationship.

There is a fungus and a photosynthesizing partner like algae.

It's a bond that was born, as they say, when Alice Algy took a lichen to Freddie

fungus. But that simple description covered up a larger mystery.

How could two different lichen species combine the same building blocks, same fungus,

same algae, and yet they look very different, they have different chemistry,

and some of them even have distinctly different ecology.

Toby Sprabilla, an evolutionary biologist at the University of Montana and the University of Grots in Austria.

He and his colleagues studied two lichen species that fit that bill.

Same underlying parts, different color and chemistry.

They ground the lichens up and then analyze their RNA.

And what they expected to find was two genomes, one fungus, one alga.

And what we found is that at the end of a lot of analysis we had three genomes not two and this

was really surprising. The third genome was from a type of yeast and the more

yeast present the more yellowish and more toxic the lichen was.

The study appears in the journal Science.

But how could scientists spend so many years studying these lichens

and still miss this crucial third species.

Shprobilla says it could have been the type of genetic sequencing.

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