How did life develop on Earth? No one really knows, although many scientists believe that meteorites could have brought some molecules that later became DNA. Now scientists from the University of York have shown how this process might work – they managed to prove that meteorite molecules have potential to become DNA.
It is difficult to put these findings into simple words, but bear with us. There are organic molecules in meteorites called amino nitriles. They are precursors to amino acids. Scientists managed to show in their research that amino nitriles can form 2-deoxy-D-ribose, backbone of DNA, by interacting with interstellar ice. This challenges conventional theory that amino acids were on Earth long before DNA was formed. This research may serve as an argument that amino acids and pieces of DNA were introduced to Earth from space and finished forming here.
Organic molecules that are needed to form the DNA had to come from somewhere. They either developed together with Earth through billions of years, or they came to our planet with a meteor shower. Some previous researches showed that there were some molecules in ice comets that could be used in developing DNA. This is actually what sparked the initial interest of scientists to start this research. They wanted to see if those molecules could in fact evolve to form DNA. This would mean that DNA was formed before amino acids were present on Earth.
Life on Earth became possible after so called ‘chemical evolution’- a process during which essential molecules were formed. Obviously, DNA is the crucial molecule for life to form, but scientists were not sure where its backbone 2-deoxy-D-ribose originated from. Mino nitriles could have brought such molecules as formaldehyde, acetaldehyde, glycolaldehyde, to come together before life started. However, some help from meteor shower would make sense in terms of accelerated process and missing parts of DNA being added to the mix.
Obviously, this research just outlines one of possibilities how it might have happened. Dr Paul Clarke, one of the authors of the study, said: “We have demonstrated that the interstellar building blocks formaldehyde, acetaldehyde and glycolaldehyde can be converted in ‘one-pot’ to biologically relevant carbohydrates – the ingredients for life”. But if it happened remains a mystery.
Origins of organic molecules on Earth are one of the biggest mysteries in science. Furthermore, it is unlikely that it is going to be resolved any time soon. However, it is good that new researches bring new hypothesis to the table that can be checked and discussed thoroughly.
Source: University of York