Phylogeny: Rewriting evolution

[Techne]

Tiny molecules called microRNAs are tearing apart traditional ideas about the animal family tree.

Kevin Peterson grabs a pen and starts to scribble an evolutionary tree on the paper tablecloth of a bar in Hanover, New Hampshire. Drawing upside down to make it easier for me to see, he maps out the standard phylogenetic tale for placental mammals. First, Peterson scratches a line leading to elephants, which branched away from the rest of the placentals around 90 million years ago. Then came dogs, followed by primates (including humans) and finally rodents — all within a frenetic 20 million years. This family tree is backed up by reams of genomic and morphological data, and is well accepted by the palaeontological community. Yet, says Peterson, the tree is all wrong.

A molecular palaeobiologist at nearby Dartmouth College, Peterson has been reshaping phylogenetic trees for the past few years, ever since he pioneered a technique that uses short molecules called microRNAs to work out evolutionary branchings. He has now sketched out a radically different diagram for mammals: one that aligns humans more closely with elephants than with rodents.

“I've looked at thousands of microRNA genes, and I can't find a single example that would support the traditional tree,” he says. The technique “just changes everything about our understanding of mammal evolution”.....

Read on, some fascinating work.

The suggested modified tree:

[Swa]

When is the madness going to stop? And don't tell me they're going to have lab elephants now.

[Chevron]

When is the madness going to stop? And don't tell me they're going to have lab elephants now.

What madness? New evidence that contradicts previous findings need to be brought to light. Much better than burying our heads in the sand and remaining ignorant.

[Swa]

What madness? New evidence that contradicts previous findings need to be brought to light. Much better than burying our heads in the sand and remaining ignorant.

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