19 Jun 08

Scientists studying the ‘living fossil’ amphioxus have found evidence of dramatic genetic events that shaped the bodies of humans and all other vertebrates.

In 1991 Oxford University scientists were the first to start investigating the genetic heritage of amphioxus, a creature described as an ‘animated anchovy fillet’, which is the closest living thing to the ancestor of all vertebrates.

Now an international team including three Oxford University scientists, publishing in this week’s Nature, show that the amphioxus genome reveals evidence for two genetic events in which the entire genome of our ancient, proto-vertebrate ancestor was duplicated.

Many believe these duplications may have provided vital genetic ‘raw materials’ for evolution to shape the complex nervous system, skeleton and organs that make humans and all other vertebrates different from other animals.

‘What is remarkable is just how little amphioxus has changed from this ancient ancestor despite over half a billion years of evolution,’ said Professor Peter Holland of Oxford University’s Department of Zoology, one of the lead authors of the paper and head of the Oxford team which began the work in 1991. ‘Amphioxus gives us the basic chassis of a vertebrate-like animal, a framework that has been elaborated on by millions of years of vertebrate evolution to produce complex organs such as the brain, the kidney and the pancreas found in backboned animals today, including us.’

The idea that vertebrate genomes were shaped by ancient genome-wide duplications was first suggested in 1970. However, the new research shows definitively that such duplications occurred, that they happened just before the Cambrian period over 500 million years ago, and that there were two distinct events.

Professor Peter Holland said: ‘The amphioxus genome gives us an amazing insight into what the genome of our ancient aquatic ancestors looked like over half a billion years ago. It’s particularly gratifying that, seventeen years after research at Oxford began into amphioxus, we are finally unlocking the secrets of this fascinating animal that is so pivotal in the story of our own evolution.’

The original work at Oxford University during the 1990s was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) that also supported one of the Oxford co-authors.

Read more about this story and genome duplication on the Oxford Science Blog.

• A report of the research, entitled ‘The amphioxus genome and the evolution of the chordate karotype’ is published in Nature on 19 June 2008.
• The Oxford co-authors are Professor Peter Holland (whose research is supported by the Wellcome Trust) and BBSRC DPhil student Thomas Butts of Oxford University’s Department of Zoology and Dr Rebecca Furlong, a Junior Research Fellow of Christ Church whose research is supported by Oxford’s John Fell Fund.
• The massive DNA sequencing effort was undertaken by researchers at the US Department of Energy Joint Genome Institute in California, while the extensive analysis involved a large international collaboration of scientists from the UK, USA, Japan, and Switzerland.