Theoretical origin of life: excerpt from Neil Thomas book (Introduction)

by David Turell , Thursday, August 19, 2021, 00:26 (980 days ago) @ David Turell

It ain't as easy as Dawkins claims:

https://evolutionnews.org/2021/08/myths-monsters-and-lifes-elusive-first-step/

"We might, therefore, do well to pause over the truth status and indeed even the logic of Dawkins’s notion of “entities sufficiently simple to have come into existence by chance,” and establish whether such a notion can be supported by experimental evidence — especially since recent advances in molecular biology show that the humblest bacterium contains more genetic information than the instruction manual for NASA space probes. The very notion of a simple biological entity has become deeply problematical with our increasing knowledge of the molecular world in the last half century, and one might therefore wish to query whether such a thing can exist in nature.

[The Miller-Urey 1953 lightning in a bottle experiment is reviewed]

***

"...the media interest in the Miller-Urey experiment is unsurprising. However, the complete chemical pathway devoutly hoped for by many in the wake of the experiment was not to materialize. In fact, the unlikelihood of such a materialization was underscored in the very same year that the Miller-Urey experiment took place, when Francis Crick and James Watson succeeded in identifying the famous double helix of DNA. Their discovery revealed, among other things, that even if amino acids could somehow be induced to form proteins, there was more to the story. Life also depends on nucleic acids, one of which is deoxyribonucleic acid or DNA, where the vital information needed to replicate and operate any given organism is encoded.

"Proteins and DNA must be able to work together. DNA is both highly complex and highly specific, to the extent that just small differences in its letter sequences can make the difference between a living, thriving animal and a stillborn. Proteins are indispensable, but they do not have the capacity to store and transmit information for their own construction. DNA, on the other hand, can store information but cannot manufacture anything or duplicate itself. It’s a chicken-and-egg situation, so much so that Francis Crick was once moved to comment that the beginnings of life seemed impossible, barring a miracle, since “so many are the conditions which would have to be satisfied to get it going.”

"Finally, it had to be conceded that life was unlikely to form at random from the so-called “prebiotic” substrate on which scientists had previously pinned so much hope. (To this day, biochemists remain ignorant of the modalities of a jump from amino acids to proteins, and the origin of nucleic acids is similarly shrouded in darkness.) To complicate things even further, it is now widely disputed whether the early atmosphere of the Earth postulated by Miller and Urey would have been such as they assumed, and so it may not have supported the formation of the organic compounds they identified. Hence the problem appears now to extend to include the origin of the basic building blocks themselves.

"The hope that life may be somehow “dormant” in chemicals, waiting to be unlocked when the correct combination of chemicals clicks into place, as it were, has clearly suffered a signal reverse."

Comment: so much for origin of life experimentation. An other point made is that the chemicals used in experimental labs are purified, not at all like the natural ones lying about on the early Earth.