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One of the building blocks of life may have formed in heated regions near hot stars, scientists have claimed.

They found that cosmic hot spots near stars are excellent environments for forming molecular rings containing nitrogen, which give rise to DNA.

If confirmed, the study could have implications for where life on Earth began.

The research was carried out at Berkeley Laboratory in California. The scientists said regions near hot stars could be the prime location for forming DNA. One of the scientists said these regions were like a 'cosmic barbeque'. Shown is a composite image of an energetic star explosion taken by the Hubble Space Telescope

The research was carried out by the US Department of Energy's Lawrence Berkeley National Laboratory and the University of Hawaii at Manoa.

They described an experiment in which they recreated the conditions around carbon-rich, dying stars to find out how certain molecules formed.

'This is the first time anyone's looked at a hot reaction like this,' said Dr Musahid Ahmed, a scientist in the Chemical Sciences Division at Berkeley Laboratory.

And he said the results showed that DNA could have been born in these regions, in what he calls a 'cosmic barbeque'.

For decades, astronomers have pointed their telescopes into space to look for signatures of molecules that could form DNA, Dr Ahmed explained.

Specifically, they have been looking for nitrogen-containing double carbon rings called quinolone.

They focused mostly on the space between stars called the interstellar medium - but no one had spent much time look in stellar environments for these rings, although they have been theorised as prime locations.

So, to recreate the conditions near a star, Dr Ahmed and his colleague used the Advanced Light Source (ALS) at Berkeley Laboratory.

At the ALS, the researchers used a device called a hot nozzle, previously used to successfully confirm soot formation during combustion.

In Dr Ahmed's study, the hot nozzle was used to simulate the pressures and temperatures near carbon-rich stars.

Into the hot nozzle, the researchers injected a gas with a mixture of nitrogen, carbon and hydrogen to see which molecules formed.

At a temperature of 700 Kelvin (425°C or 800°F), they found that the nozzle transformed the gas into one containing quinolone, and also isoquinoline, considered the next step up in terms of complexity.

That temperature - or higher - is what would be expected near hot stars, providing an ideal region for DNA to form.

DNA (illustrated), or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person's body has the same DNA

'There's an energy barrier for this reaction to take place, and you can exceed that barrier near a star or in our experimental setup,' Dr Ahmed said.

'This suggests that we can start looking for these molecules around stars now.'

According to the researchers, quinolone and isoquinoline can be created in these hot environments and then be ejected with the stellar wind to the interstellar medium - the space between stars.

'Once ejected in space, in cold molecular clouds, these molecules can then condense on cold interstellar nanoparticles, where they can be processed and functionalised,' co-author of the study Dr Ralf Kaiser added.

'These processes might lead to more complex, bio-relevant molecules such as nucleobases of crucial importance to DNA and RNA formation.'

The study was published in the Astrophysical Journal.