Register for an account


Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.


Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

#50: Confirmed: 1969 Meteorite Brought Genetic Building Blocks From Space

More evidence that asteroids may have led to the emergence of life on earth.

Murchison Meterorite Fragment Image: NASA | NULL


Sign up for our email newsletter for the latest science news

In June astrobiologists announced [pdf] they had found a key component of genetic material within a meteorite. The discovery supports the idea that asteroid bombardment four billion years ago may have jump-started the emergence of life.

Zita Martins of Imperial College London and her colleagues identified the organic molecules in the 4.6-billion-year-old Mur­chison meteorite, a carbon-rich rock that fell to Earth in Australia in 1969. Earlier researchers had detected subunits of DNA and RNA, called nucleobases, in the meteor­ite. But nobody could be sure whether the nucleobases were extraterrestrial or were simply soil contaminants.

Martins found the answer by extracting two molecules from the meteorite: uracil, a nucleobase found in RNA, and xanthine, an intermediate in the synthesis of DNA and RNA. She then compared the ratio of the two isotopes of carbon (carbon 13 and carbon 12) in them and found that the heavier carbon 13 predominated and matched the ratio found in carbon-containing chemicals created in space. By contrast, soil samples from the meteorite’s fall site contained uracil with more carbon 12.

“This is the first time anybody has proved that nucleobases in a meteorite are extraterrestrial,” Martins says. The results imply that prebiotic chemistry may be bubbling up in other parts of the cosmos too. “Meteorites and comets bombarded other planets,” Martins says. “So it means that the building blocks of life were delivered to other points in our solar system. If these building blocks were synthesized in space, they could be widespread throughout the universe.”

2 Free Articles Left

Want it all? Get unlimited access when you subscribe.


Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 75%


Already a subscriber? Register or Log In