Jerry Lewis
Beach Fanatic
http://www.csmonitor.com/Science/20...ls-Scientists-discover-traces-of-DNA-in-space
A team of scientists led by NASA's Michael Callahan appears to have added some critical components to the list of space-borne building blocks raining onto Earth's surface: a class of chemicals called nucleobases. Nucleobases combine to carry the genetic information found in DNA molecules, the molecules that orchestrate an organism's form and functions.
In results reported this week in the Proceedings of the National Academy of Sciences, the team analyzed the chemical makeup of a dozen carbon-rich meteorites plucked from different locations in Antarctica and Australia.
They not only found nucleobases widely found in organisms on Earth, compounds such as adenine and guanine, two of the four bases found in DNA. They also found related compounds, which the team dubbed "nucleobase analogues," that aren't found on Earth and in effect are new to science.
Over the years, scientists have found amino acids, which are needed to form proteins, with unambiguous space-based origins. And meteorites have carried the chemicals necessary to make cell walls.
Even nucleobases have been detected in meteorites before, notes Dr. Callahan. But scientists have had a hard time convincing themselves and others that the nucleobases came from space. They could represent contamination a space rock picked up after it landed.
"We do see biological nucleobases in ice and soil samples" collected from the places where the meteorites were found, he says. "That's only natural."
But, he adds, the mix and distribution of the nucleobases typically found in ice and soil are far different that those found in the meteorites the team analyzed.
And those new-to-science compounds are definitely not earth contamination. "We don't see any nucleobase analogues whatsoever" in the ice and soil, he says.
A team of scientists led by NASA's Michael Callahan appears to have added some critical components to the list of space-borne building blocks raining onto Earth's surface: a class of chemicals called nucleobases. Nucleobases combine to carry the genetic information found in DNA molecules, the molecules that orchestrate an organism's form and functions.
In results reported this week in the Proceedings of the National Academy of Sciences, the team analyzed the chemical makeup of a dozen carbon-rich meteorites plucked from different locations in Antarctica and Australia.
They not only found nucleobases widely found in organisms on Earth, compounds such as adenine and guanine, two of the four bases found in DNA. They also found related compounds, which the team dubbed "nucleobase analogues," that aren't found on Earth and in effect are new to science.
Over the years, scientists have found amino acids, which are needed to form proteins, with unambiguous space-based origins. And meteorites have carried the chemicals necessary to make cell walls.
Even nucleobases have been detected in meteorites before, notes Dr. Callahan. But scientists have had a hard time convincing themselves and others that the nucleobases came from space. They could represent contamination a space rock picked up after it landed.
"We do see biological nucleobases in ice and soil samples" collected from the places where the meteorites were found, he says. "That's only natural."
But, he adds, the mix and distribution of the nucleobases typically found in ice and soil are far different that those found in the meteorites the team analyzed.
And those new-to-science compounds are definitely not earth contamination. "We don't see any nucleobase analogues whatsoever" in the ice and soil, he says.
