There is a common thread of truth that has underpinned all of evolutionary biology as we know it. For life to exist in its current form today, certain biological molecules would have to have been formed under the right conditions. Modern life relies entirely on some form of genetic code to pass on information (either DNA or RNA), proteins and enzymes to carry out specific functions (like protection or the synthesis of larger molecules), and lipids to support the function of the other two. The problem lies in the fact that they would have had to form at the exact same time to create life, and that seems like insanity. Until now.
You may be asking why on earth all three of these molecules would have to be present at the same time, which is an interesting question. DNA as we know it relies on a number of proteins to synthesize more DNA, to replicate and to transcribe and translate that message into proteins. This presents an issue because if we don’t have proteins we can’t have DNA, and if we don’t have DNA, we can’t pass on the message for proteins. The same goes for lipids in that fatty acids are required for some protein functions and to establish a closed environment, but proteins are responsible for much of the synthesis of fatty acids.
Early experiments, however, showed that it was possible to create some of the individual pieces that these larger biological molecules are made of in the conditions present on early earth. One famous one was done by Stanley Miller under the supervision of Harold Urey (now called the Miller-Urey experiment), in which they replicated the earth’s atmosphere by combining water, ammonia, methane and hydrogen and sent a spark through the gasses to simulate lightning. This resulted in the creation of more than 20 amino acids within the flasks and provided evidence that early proteins could be made without biosynthetic pathways.
Now new evidence has been published in Nature Chemistry and proposes that the presence of hydrogen cyanide, hydrogen sulfide and ultraviolet light can react when catalyzed by copper to create precursor molecules that could lead to the creation of nucleic acids and eventually proteins and lipids without the need for complex reactions catalyzed by biological molecules. If this is possible then it could very easily explain how, if all of these were present in a particular pool of water somewhere on earth under the right conditions, it is possible to form early compartmentalized life capable of basic metabolic activity and eventually replication.
Now all we need to do is create life from these molecules using a test tube and recreate what took the world millions of years to do, and then we will have proof that life could start here on earth. If this isn’t cool then I don’t know what is.
