Figure 1:
Schematics of nucleobases formation by meteorite impact on earth.
(August 18, 2015) A
new study shown that meteorite impacts on ancient oceans may have created
nucleobases and amino acids. Researchers from Tohoku University, National
Institute for Materials Science and Hiroshima University discovered this after
conducting impact experiments simulating a meteorite hitting an ancient ocean
(Fig. 1).
With precise analysis of the products recovered after
impacts, the team found the formation of nucleobases and amino acids from
inorganic compounds. The research is reported this week in the journal Earth
and Planetary Science Letters.
All the genetic information of modern life is stored in DNA
as sequences of nucleobases. However, formation of nucleobases from inorganic
compounds available on prebiotic Earth had been considered to be difficult.
In 2009, this team reported the formation of the simplest
amino acid, glycine, by simulating meteorite impacts. This time, they replaced
the carbon source with bicarbonate and conducted hypervelocity impact
experiments at 1 km/s using a single stage propellant gun (Figure 2).
Figure 2: Single
stage propellant gun at National Institute for Materials Science
Japan used for the
hypervelocity impact experiments.
They found the formation of a far larger variety of life's
building blocks, including two kinds of nucleobases and nine kinds of
proteinogenic amino acids. The results suggest a new route for how genetic
molecules may have first formed on Earth.