Breakthrough gives 3-D vision of dawn of life

LONDON, Aug 10 (Reuters) A new technique allowing virtual dissections of half-billion year old fossil embryos is producing the first three-dimensional images of the dawn of life.

It reveals a universe of detail impossible using previous methods, and researchers at Bristol University in southwestern England said it was pushing back the frontiers of science much as the scanning electron microscope did half a century ago.

''We are looking at the dawn of life,'' lead researcher Phil Donoghue told Reuters. ''Because of their tiny size and precarious preservation, embryos are the rarest of all fossils.'' ''But these fossils are the most precious of all because they contain information about the evolutionary changes that have occurred in embryos over the past 500 million years,'' he added.

In contrast to existing methods of exterior observation or destructive sectioning of fossil embryos, synchroton-radiation X-ray tomographic microscopy (SRXTM) leaves the tiny fossils untouched but gives graphic details of their structure.

The team used a 500-metre wide particle accelerator in Switzerland to deep scan the minute fossils and then fed the information into a computer which generated complete 3-D images of the internal structures in fine detail.

''The best analogy is with a medical CT scan ... but at 2-3,000 times the resolution,'' Donoghue said. ''We can see details less than 1,000th of a millimetre in dimension.'' ''We can look at any and every part of the fossil inside and out without harming it and then virtually dissect it however we like,'' he added.

The team, which published their findings in the science journal Nature, said their discoveries could roll back the evolutionary history of arthropods like insects and spiders.

In one case they had found hitherto hidden details of the interior structure of an ancient relative of the living penis worm, and in another they had seen embryonic worm segments unlike those found in living specimens today.

''SRXTM provides a non-invasive method of analysis of small and microscopic fossil materials unlocking the finest details of reserved anatomy from fossilised remains,'' they wrote.

''The method has wide applicability in the study of microscopic structures and may thus bring about a revolution in palaeontology on a par with ones brought about by the scanning electron microscope,'' they added.

Reuters AKJ DB0901