ORGANISMS similar to lichen colonised the land about 1.3 billion years ago,
hundreds of millions of years earlier than had been thought.
Blair Hedges鈥檚 team at the University of Pennsylvania compared 119 genes
common to fungi, land plants and animals. By looking at the differences, the
researchers were able to estimate when these major groups diverged. They found
that fungi reached land first, with the first land plants appearing between 1
billion and 700 million years ago (Science, vol 293, p 1129).
Biologists had expected the molecular clock to go back further than fossils,
the earliest of which are only 480 million years old. 鈥淏ut I had no idea that
land plants and fungi are that old,鈥� Hedges says.
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