US markets found some support from the US central bank's decision to leave interest rates on hold at 1.75%, announced at 1815 GMT. 

In late afternoon trade in New York on Tuesday, the blue-chip Dow Jones index was trading 0.9% up on the day at 9,898 while the Nasdaq was 0.3% higher at 1,584. 

The Nasdaq index - where many of the world's most important technology firms are listed - fell more than 2% on Monday, sending shares around the world lower. 

And European share indexes fell heavily on Tuesday morning, with technology, telecoms and media shares (TMTs) taking the brunt of the slump. 

During morning trade, London's FTSE 100 index of leading shares dropped 120.4 points to stand at 5,082.7, its lowest level since 28 February. 

Amongst the biggest losers was mobile phone giant Vodafone, which failed to muster a revival after it lost 10% of its value on Friday. 

The leading indexes in Frankfurt and Paris also slid significantly, with the media firm Vivendi Universal slumping 8% while Deutsche Telekom hit a fresh all-time low. 

Oil under pressure

US investors have been shaken by the recent round of corporate results which failed to deliver convincing proof that the economic recovery is truly underway. 

Asian shares also fell heavily

Japan's leading Nikkei index fell 235 points to 11,316 during the day - a fall of over 2%. 

Part of the problem has been the change of fortune for the heavyweight oil companies. 

While energy giants such as BP, Shell and TotalFinaElf had previously been helping to offset losses from TMTs, all three firms fell more than 2% on Tuesday. 

The sudden bearish stance is due to Iraq's decision to lift its self-imposed export embargo, weakening the outlook of the crude oil price. 

Fighting back

The FTSE managed to scrape back some of its losses, to close 83 points lower at 5,120. 

This is the index' lowest close in nine weeks. 

And Vodafone, which dropped 5% to 92p in the middle of the morning, clawed back to 95p but continues to languish at a four-year low. 

Germany's Dax index fell below the key psychological 4,800 point level for the first time since late February, before pulling back to 4,851 by 1550 GMT. 

France's Cac closed 71 points lower at 4,296, even though Vivendi managed to recover from the slump prompted by a credit rating cut from Standard and Poor's. 

The information will prove crucial to researchers investigating the human genome, the complete set of biochemical instructions used by cells to build and maintain our bodies. 

It is remarkable that we were able to complete the mouse genome in such a short time and with such great accuracy

Dr Robert Waterston

"The mouse is a key model organism for humans," the Sanger Institute's Dr Tim Hubbard, one of the lead researchers on the project, told BBC News Online. 

"Their genomes are so similar that you can just compare the two directly. If there are mouse genes we know something about, we can now find genes that look the same in humans." 

Some refinement

The mouse data have been produced by a number of US and UK institutions, funded by the National Institutes of Health in America and the Wellcome Trust in Britain. 

In contrast, the work done by the international Mouse Genome Sequencing Consortium has been posted openly on the net. Anyone can browse and use the information. 

The work is not quite complete. About 4% of the genome still needs to be determined and researchers say further proofing of the current "draft" assembly will inevitably lead to some refinement. 

Nevertheless, the consortium is delighted with its effort and the speed with which the job has been done. It has only taken about a year. 

Similar numbers

"It is remarkable that we were able to complete the mouse genome in such a short time and with such great accuracy," said Dr Robert Waterston, from the Washington University School of Medicine in St Louis, one of the main institutions involved in the project. 

The mouse has a fantastic sense of smell and you can already see that in the genes

Dr Tim Hubbard

The mouse genome is bundled into 20 chromosome pairs and the current analysis suggests that it is about 2.7 billion base pairs, or "letters", in size. 

This makes it slightly smaller than the human genome, which has about 3.2 billion base pairs spread out over 23 pairs of chromosomes. 

The analysis also suggests the rodent has about 30,000 genes, a figure broadly similar to humans. 

Sick mice

"The mouse has a fantastic sense of smell and you can already see that in the genes," said Dr Hubbard, who has been analysing the DNA sequence at the European Bioinformatics Institute in Cambridge, UK. 

"It has a lot more genes than humans connected with olfactory receptors. 

"So, the animal has its specialities and even looking at those differences will help us understand those things which are critical to humans that mice don't have. But the basic biology, the basic physiology, is very similar to humans, and having this new information is going to consolidate our understanding of what are the key parts for making a vertebrate." 

Scientists can work out what human genes do by "knocking out" similar looking genes in mice and studying the results. 

Researchers can also trace the malfunctioning genes responsible for disease by examining sick mice that display symptoms apparently similar to human conditions. 

Famous anniversary

With the help of the mouse data, scientists should now finish completely their decoding of the human genome by April next year - just in time for the 50th anniversary of Crick and Watson's discovery of the helical structure of DNA. 

Analysis of the mouse data also confirm researchers' initial assessment that humans have somewhere in the region of 30,000 genes. 

This figure came as a surprise to many people when it was announced last year - some thought the more sophisticated an animal was, the higher would be its gene count. 

Genome studies now show that sophistication in an organism comes from the way its genes interact. 

By Mark Ward  BBC News Online technology correspondent

Scientists have developed software that simulates 100 years of worldwide weather patterns in order to refine predictions about global warming and its effect on climate. 

Climatologists already have some ideas about climate change over the next 50 years, but they need the help of thousands of people running the simulation to find out the full breadth of potential outcomes. 

The 100-year simulation software is expected to be ready in late summer and those downloading it must be prepared to let the model run for at least eight months. 

A century of weather

The climateprediction.com experiment is similar to the Seti@home project, started in 1997, that uses idle home computers to look for signs of alien intelligence in radio signals collected by telescopes. 

Extreme weather has been blamed on climate change

"The Seti@home project is analysing data from a central source, we are generating it on PCs and will analyse it ourselves," said Dave Frame, a climateprediction.com developer and researcher at the University of Oxford department of Atmospheric, Oceanic and Planetary Physics, UK. 

Each simulation carried out by climateprediction.com participants will be unique because all of them will use slightly different starting conditions. 

"This is a fully-fledged research climate model," said Dr Myles Allen, project leader for climateprediction.com and a physicist in the Space Science and Technology Department of the Rutherford Appleton Laboratory. 

"It's not a stripped down 'toy' version, so the runs take time," he said. 

The unpredictable physics of weather patterns means that they could generate very different end results. 

The simulation will cover the hundred years from 1950 to 2050. 

The results of the simulations will be returned to the climateprediction.com team who will then pick the ones that generated global temperature changes similar to those seen during the period 1950 to 2000. 

All outcomes

Although it is impossible to forecast weather patterns for specific regions many years ahead, phenomena such as global temperature patterns do seem predictable, said Dr Allen. 

"That's one of the most intriguing things about the planet," he added. "Its large scale behaviour is simpler than its small scale behaviour." 

Quantifying the uncertainty is something we cannot do at the moment

Dr Myles Allen, project leader

At the moment climatologists had only explored a small fraction of all the possible outcomes and this had inevitably led to disputes about the effects of global warming, he said. 

"Quantifying the uncertainty is something we cannot do at the moment," he said. 

The project needed at least 20,000 participants and would cap numbers at two million, said Dr Allen. 

To reward participants, the simulation will be interactive and will let people fly around their programmed planet and watch how weather patterns change. 

"We cannot just tell participants: 'thank you very much'", said Dr Allen "They have to get something back out of this, too." 

The simulation software should be ready in time for August to coincide with a UN conference held to mark the 10th anniversary of the Earth Summit in Rio de Janeiro that attempted to start tackling problems wrought by climate change. 

By Christine McGourty  BBC science correspondent

We remember Scott and we remember Shackleton because we like these glorious English failures and Bruce wasn't like that at all

Gordon MacPherson, composer

William Speirs Bruce ran one of the most successful expeditions during what has since become known as the Heroic Era of Antarctic exploration. 

Now, there is a move to raise awareness of this scientist and adventurer, who headed up the Scottish National Antarctic Expedition 100 years ago. 

Very experienced

Bruce wanted a place on Britain's "Discovery" expedition - which was ultimately to be led by Scott, with Shackleton among the crew. He was snubbed by the organisers. 

William Speirs Bruce: Succeeded where others failed

Geoff Swinney of the Royal Museum of Scotland, in Edinburgh, who is organising an exhibition on Bruce to open next year, says it was a mistake to overlook Bruce. 

Unlike Scott and Shackleton, Bruce had actually been to Antarctica before, on a whaling expedition. He had a wealth of other experience, too. 

Rival bid

"He worked for nearly a year at the meteorological station at the top of Ben Nevis, training himself in the methodology of recording weather and climate," Geoff Swinney told BBC News Online. 

Bruce began to believe that polar exploration was becoming more of an adventure than a science

David Munro, Scottish Royal Geographical Society

"So, by the time Britain was planning an Antarctic expedition, he was by far the best qualified person to be on that expedition, with a wealth of polar experience and polar condition experience." 

Sir Clements Markham, of the Royal Geographical Society, was angered by Bruce's move to launch a rival expedition. 

Bruce raised funds from the wealthy Coats family of Paisley, near Glasgow, and set off on the voyage he dubbed the Scottish National Antarctic Expedition. 

Real science

He took a converted Norwegian whaling ship, which he named the Scotia. Unlike Scott, he had no interest in a race to the South Pole - his priority was to do original scientific research. 

David Munro, president of the Scottish Royal Geographical Society, in Glasgow, said: "Bruce began to believe that polar exploration was becoming more of an adventure than a science and it was only the science he was interested in. 

"From that point of view the expedition was a huge success - they discovered several hundred miles of previously unknown Antarctic continent, collected a wealth of geological and biological specimens and when they came back, published six volumes of scientific reports on their results." 

The aim had been to establish a scientific research station on the continent, but bad weather prevented that. 

Instead, they set it up on a sub-Antarctic Island, called Laurie Island, where scientists are still working today. 

Penguin piper

A series of striking images remain from the voyage, including a classic photo of a piper in a kilt, apparently serenading a penguin on the ice. 

The penguin was unmoved

"The idea was they were going to play it jigs, strathspeys, reels, slow marches, etc, and see if the penguin had any reaction. 

"It stood unmoved. Of course, it's largely unmoved because it's tied to the foot of the piper." 

The SRGS is mounting a two-year campaign to raise awareness of the expedition of the Scotia. 

Climate change

They are trying to raise funds for another expedition to the Antarctic early next year, to celebrate the achievements of Bruce and continue the science he began in a series of research projects which will be carried out mainly on the island of South Georgia. 

Laurie Island, further south, is more difficult to reach and the research possible there is more limited. 

John Gordon, of Scottish Natural Heritage, is one of the scientists who will be leading that expedition. 

"It will reflect the ideals of Bruce, rather than do a journey for the sake of it. We want to set out on an expedition that would produce serious scientific results. 

"We've put together a team of about 10 scientists and they'll be doing a lot of glaciology, looking at past climatic conditions on the island. 

"We want to investigate how the climate and environment on South Georgia has changed in the last 10-15,000 years, since the last glaciation." 

English failure

As part of the Scotia celebrations, the Dundee-based composer Gordon MacPherson has been commissioned to write a symphony to be premiered in the summer. 

The composer said Bruce had become bitter to some extent at being overlooked for the Discovery expedition and he had tried to capture the essence of how it must have felt to be so forgotten. 

He said it was precisely because the expedition was so well run that Bruce was so little known today. 

"There was a lack of drama to the voyage," said MacPherson. "It's not the sort of thing that would sell well in tabloid newspapers. 

"We remember Scott and we remember Shackleton because we like these glorious English failures and Bruce wasn't like that at all because he was so well prepared for the trip."