What would we do without DNA? Of course we would be nonexistent without the hundreds of nucleotides that are packaged into each of our microscopic cells. The millions of cells within our body each contains a set of instructions known as genomes, and DNA makes up our genomes. These genomes pretty much determine everything, from our hair color to our height. A portion of this DNA is passed onto offspring from parents during reproduction, which is why individuals are able to inherit some of their parents’ traits. Each organism has unique DNA because of the unique arrangement of nucleotides, but all DNA is composed of the same nitrogen-based molecules.
This discussion of DNA also necessitates the question of RNA. Even though DNA consists of the blueprints necessary to create proteins that carry out functions within the cell, this process can only be carried out by passing on this important information to RNA. This transfer of information is known as transcription. It is then through translation that the base sequence of RNA is used to join amino acids and create proteins. The most interesting part about RNA is that it is able to function as both a gene and a protein. But the dilemma arises when one closely examines the processes for protein synthesis. If DNA provides the blueprints for protein synthesis for the different types of RNA to carry out, and if it’s these protein sequences that create the basis for DNA, one must ask, “Which came first, DNA or RNA?”
The more commonly accepted abiotic synthesis, or chemical evolution theory, starts with the fact that the first cells originated/evolved on Earth from materials in a primordial soup. The primordial soup included inorganic and abiotic chemicals. The earliest organism living around this time period included prokaryotic, simple organelle cells. The inorganic chemicals in the primordial soup then had to undergo abiotic synthesis to form simple organic molecules, or monomers such as monosaccharides, monomers, amino acids, etc. Furthermore, the monomers had to undergo dehydration synthesis in order to become polymers, such as proteins, nucleic acids, etc. Dehydration synthesis is the process of joining two molecules through the removal of water. The third step included proto cell formation through the forming of the membrane. More stable molecules and self-replicating molecules that brought us closer to the cells we have today came about through molecular selection at the molecular level. Several experiments have provided fundamental evidence of such primary processes.
As it turns out, one of the simpler structures in the universe actually possesses the key to solving the mystery of the origin of life. Further research on RNA will only bring us closer to unlocking the entire story of our existence.
