Can DNA bases be produced during molecular cloud collapse?

Abstract

Using a reasonably large chemical reaction network consisting of 421 species, we show that along with normal chemical evolution of molecular cloud during collapse and star formation, significant amount of adenine, a DNA base, may be produced after an evolution of 10^{6-7} years. This findings may shed light on whether life on earth had to begin from scratch or these molecules could have contaminated the earth from the beginning.