In molecular biology
There is a fundamental dogma that asserts that all genetic information is processed by going from DNA to RNA and finally to protein. (Ameta et al. 1304, Swadling et al. 1574a) As a result, it is considered that genes typically encode for proteins. Since they carry out numerous very necessary biological functions either structurally or catalytically as enzymes, the produced proteins are crucial for preserving life.
The catalytic regulators of the events
that take place as DNA is converted to RNA and then into other proteins as specified by the corresponding genes from each locus are called ribosomal enzymes. RNA is therefore known to be the only type of molecule known to be capable of function both as genetic and catalytic roles simultaneously (de Lorenzo 230). This general overview has provided an understanding and insight into molecular biology, and has since been accepted as the central dogma of molecular biology.
Discussion
Experiments have been performed to study the effects that environmental factors have on the process of evolution of ribozymes during protein synthesis. According to Biondi et al. (12), one of such experiments involved monitoring and comparing an in-vitro evolution of ribozymes along two different parallel trajectories, with one trajectory occurring in an environment with montmorillonite clay that has abundant sodium element while the other control trajectory lacked sodium conditions. Results from this comparison showed that the presence of sodium produced very minimal impact on the structure and function of ribozymes during the process of evolution. Sodium did not necessarily inhibit the emergence of the expected new structures as, and neither did it cause emergence of new unexpected structures.
Supported by the findings
of that experiment, Stephenson et al. (1893), drew the conclusion that the ability of RNA to produce functional structures is not improved by montmorillonte. The nature of this finding is intriguingly interesting when we consider that the minerals in montmorillonite clay had previously been shown to interact significantly with RNA .The montmorillonite minerals have been known to have the ability to bind RNA, and facilitate their formation from enzymatically activated monomers, and also to support RNA vesicle formation (Stephenson et al. 1897; Könnyű et al. 412).However, the such theoretically accepted interactions were not appreciably demonstrated from a practical perspective.
The central dogma of molecular biology
forms the cornerstone of the belief in the scientific concept of the origins of life molecules. Going by the postulation, it is acceptable for Swadling et al. (2495b), to passionately intimate that since RNA is the only type of molecule known to be capable of function both as genetic and catalytic roles simultaneously, it could also be the first entity with ability to evolve. Their work revisited the central dogma by investigating the evolutionary effects of introducing a replicator structure, and to establish if the structure could cause changes in mutation sequences. Each sequence of nucleotides was used to determine the constitutional components of the applicator such as rate of degradation, replicability and the rate of enzymatic activity. The result from this experimental setup was quite astonishing. It showed that the community of the reactant applicator which supplies the replicating monomers had a relatively increased propensity to establish a stable coexistence and develop structural adaptations. This finding shows that the applicators form an important adaptation drawn from their uniformity and finesses. According to Kun, Adam and Szathmáry (1499), populations are found to exhibit phenotypic variations resulting from the evolutions of ribosomal molecules with enzymatic activity.
Other investigated environmental factors that were thought to influence evolution
include changes in pH, temperature, ion density, counterion identity and temperature (Popović et al. 323; Koffler & Schlotterer 461). Their effects on the rate of function and effectiveness of RNA show some digression and inconsistency with the results from the experiment on the montmorillonite mineral elements. When pH and ion density are the factors under investigation, it was found out that some components which are highly promoted in a certain environment are conversely inhibited in the others. This is unlike the montmorillonite experiment whose the results were same for both presence and absence of sodium element.
The effect of magnesium and iron
which are also inorganic elements, has also been investigated in a similar experiment reviewed by Schwartz, Pauline, Dante, and Carl Barratt (269). Independent populations of isolated RNA molecules were let to evolve at different pH levels in air-tight anoxic conditions. Anoxic conditions were ideal for the experiment to mitigate technical errors from the propensity of iron to oxidize readily from atmospheric oxygen. RNA was left to cleave at room temperature for a limited reaction time of half an hour. The time limit was a necessary precaution to minimize chances of iron being oxidized by atmospheric oxygen, but it was still ample enough to allow the sequences of catalytic self-cleaving to occur. Benner et al. (358), suggest that sequences within the consortium of RNA in the experiment were then separated to distinguish active and inactive RNA and only those that were active in defined the sequence were selected. Through electro-elution, the selected active ones were separated and recovered from the gel and re-suspended then reverse transcribed and amplified. The products were then finally transcribed in an in vitro setup to generate RNA for the next evolution round. Serial repetition of the whole of this process was done up to the point when ultraviolet light shadowing showed that self-cleavage had significantly occurred (Curtis and Bartel 1118).
In the discussion of the results
of this experiment, a direct comparison of the two populations that evolved independently but under similar conditions reveals that abundances of the sequences are very similar. With an insignificant difference between them, the figures are considerably close. Many low abundance sequences occur in only one of the two populations. In contradistinction, populations that are subjected to varying conditions do show comparatively large differences in the abundances of their sequences (Long et al. 570). From the foregoing of this experiment, we find that the effect of pH and iron is applicable in understanding the evolution and role of RNA in early life because of the abundance of iron and extreme pHs available in the different environments from where life may have evolved. This conclusion from the experiment is in tandem with those from other similar experimental study setups as shown by (Curtis and Bartel 1119).
Conclusion
All the experiments described and their findings underline the evolving nature of ribozymes and their roles in protein synthesis. These studies on the process of evolution of ribozymes do critically evaluate the belief in the central dogma in molecular biology in diverse parameters. Studies by Witzany (808), attempt to challenge the universality of the theory, by subjecting experimental genetic materials to different conditions like an environment of inorganic elements, to elucidate the evolving nature of ribozymes and their roles in protein synthesis. The experimental studies emphasize on why it is important to consider the specific environments under which biopolymers evolve in order to appreciate their actual and potential significant roles in the origins of life and in the understanding of biotechnology.
Work Cited
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