'Metabolism first' theory on origin of life rejected

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Washington, January 9 (ANI): A new research has rejected the 'metabolism first' hypothesis about the origin of life, a theory that says life originated from a system of self-catalytic molecules capable of experiencing Darwinian evolution without the need of RNA or DNA and their replication.

The research was carried out with the participation of Mauro Santos, researcher of the Department of Genetics and Microbiology at Universitat Autonoma de Barcelona (UAB).

It has demonstrated that, through the analysis of what some researchers name "compound genomes", these chemical networks cannot be considered evolutionary units because they lose properties that are essential for evolution when they reach a critical size and greater level of complexity.

In the first half of the 20th century, Alexander Oparin established the "Metabolism First" hypothesis to explain the origin of life, thus strengthening the primary role of cells as small drops of coacervates, which are evolutionary precursors of the first prokaryote cells.

Dr Oparin did not refer to RNA or DNA molecules since at that time it was not clear just how important the role of these molecules was in living organisms.

However, he did form a solid base for the idea of self-replication as a collective property of molecular compounds.

Science more recently demonstrated that sets of chemical components store information about their composition that can be duplicated and transmitted to their descendents.

This has led to their being named "compound genomes" or composomes.

In other words, heredity does not require information in order to be stored in RNA or DNA molecules.

These "compound genomes" apparently fulfill the conditions required to be considered evolutionary units, which suggests a pathway from pre-Darwinian dynamics to a minimum protocell.

Researchers in this study nevertheless reveal that these systems are incapable of undergoing a Darwinian evolution.

For the first time, a rigorous analysis was carried out to study the supposed evolution of these molecular networks using a combination of numerical and analytical simulations and network analysis approximations.

Their research demonstrated that the dynamics of molecular compound populations, which divide after having reached a critical size, do not evolve, since during this process the compounds lose properties that are essential for Darwinian evolution.

Researchers concluded that this fundamental limitation of "compound genomes" should lead to caution towards theories that set metabolism first as the origin as life, even though former metabolic systems could have offered a stable habitat in which primitive polymers such as RNA could have evolved. (ANI)

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