(Video APTN)

Scientists announced on Thursday that they had produced a living cell powered by manmade DNA, a bold but controversial step in the quest to create artificial life.

While such work can evoke images of Frankenstein-like scientific tinkering, it excited hopes that it could eventually lead to new fuels, better ways to clean polluted water, faster vaccine production and more.

The inventors called their creation the world's first synthetic cell, although this initial step is more a re-creation of existing life - changing one simple type of bacterium into another - than a built-from-scratch kind.

But Maryland genome-mapping pioneer J. Craig Venter said his team's project paved the way for the ultimate, much harder goal: designing organisms that work differently from the way nature intended for a wide range of uses.

Already he's working with ExxonMobil in hopes of turning algae into fuel.

But the new cell raises serious ethical questions.

"It's very difficult to label a technology as always bad or always good, but the application continually needs to be monitored," said Jennifer Miller, Founder and Executive Director, Bioethics International.

She is concerned that in the wrong hands, "somebody with questionable ethics, such as a bio-terrorist", this technology could be extremely dangerous.

According to Miller, there are also long term, more subtle risks to be assessed if the new cells become incorporated into the natural world.

"We don't know the effects on overall ecology or even on the health of man as we continue to move forward in this scientific developments," she said.

The US administration echoed these concerns.

Following the announcement, US President Barack Obama directed the Presidential Commission for the Study of Bioethical Issues he established last fall to make its first order of business a study of the milestone.

"The commission should consider the potential medical, environmental, security and other benefits of this field of research, as well as any potential health, security or other risks," Obama wrote in a letter to the commission's chairwoman, Amy Gutmann, the president of the University of Pennsylvania.

Obama also asked that the commission develop recommendations about any actions the government should take "to ensure that America reaps the benefits of this developing field of science while identifying appropriate ethical boundaries and minimising identified risks."

Scientists for years have moved single genes and even large chunks of DNA from one species to another.

At his J. Craig Venter Institute in Rockville, Md., and San Diego, Venter's team aimed to go further.

A few years ago, the researchers transplanted an entire natural genome - the genetic code - of one bacterium into another and watched it take over, turning a goat germ into a cattle germ.

Next, the researchers built from scratch another, smaller bacterium's genome, using off-the-shelf laboratory-made DNA fragments.

Friday's report combines those two achievements to test a big question: Could synthetic DNA really take over and drive a living cell? Somehow, it did.

The researchers picked two species of a simple germ named Mycoplasma. First, they chemically synthesised the genome of M. mycoides, that goat germ, which with 1.1 (m) million "letters" of DNA was twice as large as the germ genome they'd previously built.

Then they transplanted it into a living cell from a different Mycoplasma species, albeit a fairly close cousin.

At first, nothing happened. The team scrambled to find out why, creating a genetic version of a computer proofreading programme to spell-check the DNA fragments they'd pieced together.

They found that a typo in the genetic code was rendering the manmade DNA inactive, delaying the project three months to find and restore that bit.

That fixed, the transplant worked.

The recipient cell started out with synthetic DNA and its original cytoplasm, but the new genome "booted up" that cell to start producing only proteins that normally would be found in the copied goat germ.

The researchers had tagged the synthetic DNA to be able to tell it apart, and checked as the modified cell reproduced to confirm that new cells really looked and behaved like M. mycoides.

Even while praising the accomplishment many specialists say the work hasn't yet crossed the line of truly creating new life from scratch.

It's partially synthetic, some said, because Venter's team had to stick the manmade genetic code inside a living cell from a related species.

That cell was more than just a container; it also contained its own cytoplasm - the liquid part.

In other words, the synthetic part was "running on the 'hardware' of the modern cell," according to a physics professor writing in the journal Nature, which on Thursday released essays of both praise and caution from eight leaders in the field.