Theoretical origin of life;more attempts with lab alteration (Introduction)

by David Turell , Tuesday, March 02, 2021, 19:52 (1152 days ago) @ David Turell

Another foolish attempt using existing tRNA:

https://www.sciencedaily.com/releases/2021/03/210302094102.htm

"A Ludwig-Maximilians-Universitaet (LMU) in Munich team has shown that slight alterations in transfer-RNA molecules (tRNAs) allow them to self-assemble into a functional unit that can replicate information exponentially. tRNAs are key elements in the evolution of early life-forms.

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"Transfer RNAs act as intermediaries between mRNAs and proteins: they ensure that the amino-acid subunits of which each particular protein consists are put together in the sequence specified by the corresponding mRNA.

"How could such a complex interplay between DNA replication and the translation of mRNAs into proteins have arisen when living systems first evolved on the early Earth? We have here a classical example of the chicken-and-the-egg problem: Proteins are required for transcription of the genetic information, but their synthesis itself depends on transcription.

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"In their experiments, Braun and his colleagues used a set of reciprocally complementary DNA strands modeled on the characteristic form of modern tRNAs. Each was made up of two 'hairpins' (so called because each strand could partially pair with itself and form an elongated loop structure), separated by an informational sequence in the middle. Eight such strands can interact via complementary base-pairing to form a complex. Depending on the pairing patterns dictated by the central informational regions, this complex was able to encode a 4-digit binary code.

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"The team was able to show that the system is capable of exponential replication. This is an important finding, as it shows that the replication mechanism is particularly resistant to collapse owing to the accumulation of errors. The fact that the structure of the replicator complex itself resembles that of modern tRNAs suggests that early forms of tRNA could have participated in molecular replication processes, before tRNA molecules assumed their modern role in the translation of messenger RNA sequences into proteins. "This link between replication and translation in an early evolutionary scenario could provide a solution to the chicken-and-the-egg problem," says Alexandra Kühnlein. It could also account for the characteristic form of proto-tRNAs, and elucidate the role of tRNAs before they were co-opted for use in translation."

Comment: Insane research. The group starts with complex DNA molecules and tells us that steps to life could happen this way. Fine, but this is a giant step from no molecules at all to this complex point. A waste of research grant money. After almost 70 years of research no one is any closer to figuring out the first steps, and my sneaking suspicion is we will never know.