Origin of life from Antiquity to synthetic biology. Disclosure 27
As in the text of ancient Greek atomist school, where Leucippus and Democritus (2600 years ago) defined (without seeing it) the atom as the smallest element from which all things are made, through different combinations of them. There are ancient texts that give interesting information on the origin of life and LUCA (Last Universal Common Ancestor) without apparently objective evidence. The poem “Cad Enigma Goddeu Gwion” says:
“I know the science of the stars, of the stars before the earth was made, that I was born, how many worlds there are” and then adds “I have taken many forms, I have been light, I have been a star, I have been a drop in the air before achieving a consistent shape (congenial).
In the verse 42 of the work entitled “Lao Tzu Tao Te Ching” it can be readed: “Tao produces the One, being the One shown, produces the Two, these come into existence to occur Three, which is the way of all things”. This is summarized by Charles Darwin at the end of his book “The Origin of the Species”: “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one”.
These texts do not establish scientific evidence but they show that the deductive capacity of people, different in time and space, can reach intuitions close the reality in such as enigmatic areas as the atom or the origin of life.
If we consider the One, Two and Three: the cell wall, the genetic material and the first life that finally is the way to all living current things.
Amphipathic molecules have a hydrophobic and a hydrophilic pole. Consequently these molecules, in aqueous solution are arranged in layers that curve themselves and form vesicles closed on them, leaving an inner encapsulated space.
These formations have the same properties that characterize living things: are born, grow, reproduce and die. However, these functions are performed only through basic physicochemical forces: born by electrostatic forces, grow by addition of amphipathic molecules, not because of a transformation process such as digestion, and reproduce by bipartition when the volume-surface ratio decompensates and the surface tension is not able to maintain the integrity of the vesicle. The current knowledge about them indicates that the firsts vesicles of this kind could be formed in Earth 4100 million years ago. Alexander Oparin studies from producing these vesicles and caal them “coacervates”.
Genetic material is composed by complex molecules called RNA and DNA. The existence of DNA was demonstrated in 1953 by James W. Watson and Francis Crick while Carl Woese demonstrated the existence of RNA-m in 1970. Nowadays, there is a scientific debate about the origin of these materials; it has been demonstrated that the three raw materials necessary for their formation (uracil and xanthine (guanine and adenine)) have been isolated in meteorites (Murchison Australia 1969). It seems to be a general agreement about that the RNA preceded to DNA. Thus, the first molecule became to act as an intermediary step between DNA and proteins that form following its codification.
Once studied the origin of the One (protobionts cell wall) and the Two (Genetic material) the next step is explain how and when happened their union in the Three (the consistent and the way of all things).
About the “How” there is not scientific information as the firsts fossils studied have about 3500 million years, and hypothesis about the existence of the firsts cell walls situate them 4100 million years ago. Therefore it is considered that in these 600 million years there were various forms of association, similar vesicles which could have encapsulated the firsts metabolic reactions together with the firsts molecules with replicative capacity that, finally, led to the LUCA and the three groups of primitive organisms known as: Archea, Bacteria and Eucaria.
Nowadays the so called Synthetic Biology, is establishing the conditions of the Earth between 4100 and 3500 million years ago and trying to build simple systems with the ability to reproduce and evolve; that would be a synthetic LUCA. These strategies have succeeded forming complex vesicles protobiont-like with oleic acid, has been successfully synthesizing nucleotides (adenine and guanine as a part of the DNA and RNA; and thymine, cytosine and uracil as part of RNA exclusively) that, due to a polymerization process, produce nucleic acids and are establishing the base how LUCA’s genome could be formed, from the hypothesis that this genome is formed from 200 to 1000 genes.
In conclusion, every day we have more information about the formation of the first common ancestor (which, as the atom, was described without see it), however, there are still questions about how and where occurred the association between membranes and genetic material. Current knowledge allows us to read genome but do not allow us to know the meaning of this reading as, probably, an important part of this information is not correlated with phenotypic gene expression, which is a function of the environment, and instead contains multiple internal codes (genetic switches) that allow to duplicate genetic material, control the formation of the walls or suppress a part of its reading so that the intuition, of the ancient texts that speak of light, stars, drops, the Three that is the way of all the things and that all these things evolved from a single form would acquire meaning, while recognizing that this is the result of human inference and not evidence.