Explaining the origins of the genetic code without vertical descent

Here is the result of my two-month stay at the Earth-Life Science Institute (ELSI) of the Tokyo Institute of Technology, which was made possible by ELSI’s Origins Network. I quite like the implication that life could have been an inherently social phenomenon from its very origins!

Horizontal transfer of code fragments between protocells can explain the origins of the genetic code without vertical descent

Tom Froese, Jorge I. Campos, Kosuke Fujishima, Daisuke Kiga, and Nathaniel Virgo

Theories of the origin of the genetic code typically appeal to natural selection and/or mutation of hereditable traits to explain its regularities and error robustness, yet the present translation system presupposes high-fidelity replication. Woese’s solution to this bootstrapping problem was to assume that code optimization had played a key role in reducing the effect of errors caused by the early translation system. He further conjectured that initially evolution was dominated by horizontal exchange of cellular components among loosely organized protocells (“progenotes”), rather than by vertical transmission of genes. Here we simulated such communal evolution based on horizontal transfer of code fragments, possibly involving pairs of tRNAs and their cognate aminoacyl tRNA synthetases or a precursor tRNA ribozyme capable of catalysing its own aminoacylation, by using an iterated learning model. This is the first model to confirm Woese’s conjecture that regularity, optimality, and (near) universality could have emerged via horizontal interactions alone.

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2 Comments

  1. Tom Froese said,

    February 23, 2018 at 11:48 am

    Reblogged this on 4E Cognition Group and commented:

    Many thanks to Jorge for all his hard work on implementing and running the model!!

  2. antlerboy - Benjamin P Taylor said,

    February 24, 2018 at 6:30 am

    Reblogged this on Systems Community of Interest and commented:
    Fascinating stuff!


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