Abiogenesis – Chicken and Egg Paradox

QUESTION: Abiogenesis – What is the chicken and egg paradox?

ANSWER:

One of the most fundamental problems confronting adherents to the theory of abiogenesis is the chicken-and-egg paradox. DNA depends heavily on proteins for functioning, yet protein relies upon DNA for correct sequencing. Protein cannot arise apart from DNA, yet DNA requires proteins in order to function. Thus, the difficulty is: how did two independent systems — both of which are necessary for the sustaining of life — arise simultaneously that rely on one another for survival and function?

Some origin-of-life researchers have suggested that proteins may not have been the first building blocks of life and that DNA may not have been the first information storage medium. In recent years, scientists have suggested an ‘RNA-world’ model in which RNA serves as the precursor to both DNA and proteins. RNA has the capacity to store information (like DNA) and catalyze chemical reactions (like enzymes).

Abiogenesis and chicken and egg paradox
Yet no one has been able to demonstrate how RNA could have formed on the early earth in the absence of living cells. And besides, the sheer instability of the RNA molecule would render it unsustainable in the long-term.

Furthermore, there is no known naturalistic mechanism from the RNA world to the current DNA-protein world that fundamentally characterizes life as we know it.

Cell Signaling Technology

The synthesis of new proteins is a highly regulated process that allows rapid cellular responses to diverse stimuli at the post-transcriptional level. Nine key eukaryotic translation initiation factors (eIFs) catalyze the assembly of a functional ribosomal complex in two steps – first, the formation of the 48S complex from the 43S initiation complex and mRNA followed by its subsequent joining with the 60S subunit, enabling polypeptide chain formation. Of the many steps in translation, the rate-limiting step, initiation, is subjected to the most regulatory control. Many stimuli, such as growth factors and stress, either stimulate or inhibit specific eIFs. Aside from initiation, translation can also be attenuated during elongation. For instance, elevated levels of Ca2+ or cAMP can block the action of eukaryotic elongation factor 2 (eEF2) via AMPK. Finally, upon recognition of a stop codon, eRF1 and eRF3 mediate termination of translation and ribosome disassembly and recycling

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