Scientists in the US have succeeded in developing the first synthetic living cell.
The researchers constructed a bacterium's "genetic software" and transplanted it into a host cell.
The resulting microbe then looked and behaved like the species "dictated" by the synthetic DNA.
The advance, published in Science, has been hailed as a scientific landmark, but critics say there are dangers posed by synthetic organisms.
| By Maggie Shiels Technology reporter, BBC News, Silicon Valley |
 YouTube wants users to discover and shape the world through video |
Video sharing website YouTube now gets more than two billion hits daily.
That's nearly double the number of people who tune into the US's three prime time TV stations combined, its owners Google have said.
The news comes as the site celebrates the day five years ago when the first beta version of YouTube was launched.
"I see this great growth opportunity in the online video market and we are positioning ourselves to be a leader," co-founder Chad Hurley told BBC News.
"We are a stage and we give everyone in the world an opportunity to participate and that is being a video platform for creating a solution for people to not only upload and distribute their videos on a global basis but to find and share videos."
He also said that while the two billion downloads marked a real milestone "I feel we have much further to go.
| Richard Galpin BBC News, Moscow |
 Mr Ilyumzhinov made the claims in a TV interview |
A Russian MP has asked President Dmitry Medvedev to investigate claims by a regional president that he has met aliens on board a spaceship.
Kirsan Ilyumzhinov, the leader of the southern region of Kalmykia, made his claim in a television interview.
MP Andre Lebedev is not just asking whether Mr Ilyumzhinov is fit to govern.
He is also concerned that, if he was abducted, he may have revealed details about his job and state secrets.
The MP has written a letter to Mr Medvedev raising a list of his concerns.
In his letter he says that - assuming the whole thing was not just a bad joke - it was an historic event and should have been reported to the Kremlin.
He also asks if there are official guidelines for what government officials should do if contacted by aliens, especially if those officials have access to state secrets.
Mr Ilyumzhinov said in an interview on primetime television that he had been taken on board an alien spaceship which had come to planet Earth to take samples - and claims to have several witnesses.
He has been president of Kalmykia, a small Buddhist region of Russia which lies on the shores of the Caspian Sea, for 17 years.
The millionaire former businessman has a reputation as an eccentric character.
As president of the World Chess Federation, he has spent tens of millions of dollars turning the impoverished republic into a mecca for chess players - building an entire village to host international tournaments.
 The US and Russian presidents are at the summit fresh from a new treaty |
World leaders at a summit on nuclear security in Washington have heard dire warnings of the danger of nuclear material falling into the wrong hands.
President Barack Obama, opening the biggest international meeting hosted by the US since 1945, greeted leaders from nearly 50 countries.
Officials said more should be done to prevent theft or smuggling.
Meanwhile France's leader stressed his country could not give up its own nuclear weapons.
The US welcomed a Ukrainian pledge to eliminate its stockpile of highly enriched uranium by 2012.
The two-day summit is taking place without representatives of Iran and North Korea, neither of whom were invited by the US because of the disputes over their nuclear programmes.
Israeli Prime Minister Benjamin Netanyahu dropped plans to attend the summit, reportedly because of concern that Muslim states planned to press for Israel to open its own nuclear facilities to international inspection.
'Proliferators not welcome'
The head of the International Atomic Energy Agency, Ikia Amano, said that nuclear powers needed to do more to protect nuclear materials.
 | MARDELL'S AMERICA   Perhaps some threats seem too much like fiction to be taken seriously   |
"The problem is that nuclear material and radioactive material are not well protected and member states need to better protect these materials against the theft or smuggling," he told the BBC.
"On average every two days we receive one new information on an incident involving theft or smuggling of nuclear material."
British Foreign Secretary David Miliband said that nuclear nations like Pakistan were vulnerable.
"The message from this summit is that any country can be treated as a normal country on nuclear matters if it behaves like a normal country," he said.
"Proliferators are not welcome in the modern world, nuclear proliferators especially, and I think it's a very clear message to the Iranians and others that there is an international desire to use civilian nuclear power for beneficial purposes, but not to allow it to leech into a military weapons programme that could be so dangerous, especially in a region like the Middle East."
A senior American counter-terrorism expert, John Brennan, warned that al-Qaeda had been seeking material for a nuclear bomb for more than 15 years.
"There have been numerous reports over the past eight or nine years of attempts to obtain various types of purported material," he told reporters.
"We know al-Qaida has been involved a number of times. We know they have been scammed a number of times."
President Obama and his Chinese counterpart Hu Jintao reportedly agreed at pre-summit talks to step up pressure on Iran over its atomic plans.
"The Chinese very clearly share our concern about the Iranian nuclear programme," said Jeff Bader, Mr Obama's senior director for Asia on the National Security Council.
"The two presidents agreed the two delegations should work together on a sanctions resolution in New York."
Ukrainian precedent
Just before the summit opened, Ukraine agreed to eliminate its stockpile of weapons-grade nuclear material which, the US said, was enough to build "several weapons".
White House spokesperson Robert Gibbs: "Ukraine announced a landmark decision"
US officials said Ukraine's highly enriched uranium would be removed with some US technical and financial help.
Ukraine's agreement sets a precedent that Mr Obama would like other countries to follow, the BBC's diplomatic correspondent, Jonathan Marcus, reports from Washington.
It is estimated there are about 1,600 tonnes of highly enriched uranium in the world - the type used in nuclear weapons.
Experts agree that virtually all of it is held by the acknowledged nuclear-weapons states, most of it in Russia.
Speaking in an interview before the summit opened, French President Nicolas Sarkozy said his country would not give up its nuclear weapons because to do so would be to jeopardise national security.
"I cannot jeopardise the security and safety of my country," he told CBS News.
"I have inherited the legacy of the efforts made by my predecessors to build up France as a nuclear power and I could not give up nuclear weapons if I wasn't sure the world was a stable and safe place."
Last week, the US and Russia signed a new Strategic Arms Reduction Treaty, reducing each country's deployed nuclear arsenal to 1,550 weapons.
Mr Obama has also approved a new nuclear policy for the US, saying he plans to cut the nuclear arsenal, refrain from nuclear tests and not use nuclear weapons against countries that do not have them.
 The Al Ghad report said the UFOs lit up the whole town |
A Jordanian mayor is considering suing a newspaper over an April Fools' Day report saying aliens had landed nearby.
Al-Ghad's front-page story on 1 April said flying saucers flown by 3m (10ft) creatures had landed in the desert town of Jafr, in eastern Jordan.
It said communication networks went down and frightened townspeople fled into the streets.
The mayor, Mohammed Mleihan, said parents were so frightened they did not send their children to school that day.
"Students didn't go to school, their parents were frightened and I almost evacuated the town's 13,000 residents," Mr Mleihan told the Associated Press.
"People were scared that aliens would attack them."
He immediately notified the security authorities, who he said combed the area looking for the aliens. They did not find any.
Big jokers
Al-Ghad's front page piece said the giant aliens had arrived on flying saucers lighting up the Jordanian desert town of Jafr, some 300 kilometres (190 miles) east of Amman.
Moussa Barhoumeh, Al Ghad's managing editor, said the newspaper was simply having some good natured fun on April Fools' Day, and had apologised for any inconvenience caused.
"We meant to entertain, not scare people," he said.
Mr Barhoumeh did not say why Jafr was chosen as the butt of the joke, but the area is notorious for a nearby military base that sometimes hosts US troops for joint training exercises.
Human rights groups claim the base once housed alleged al-Qaida militants, some of whom were transferred from Guantanamo Bay, but Jordan has denied the charge.
While April Fools' Day jokes appearing in the press may be a great British tradition, this is not the case in Jordan, says the BBC's Dale Gavlak in the capital, Amman.
While Egyptians are renowned as the big jokers in the Arab world, able to easily laugh at just about anything, the Jordanians are considered more serious.
Although some are trying to change that perception by hosting a yearly international comedy festival in Amman, for Jafr's mayor, this was clearly one joke that just went too far, our correspondent adds.
