• New insight into the possible origins of

    From ScienceDaily@1:317/3 to All on Fri Mar 18 22:30:36 2022
    New insight into the possible origins of life
    Experiment sheds light on the molecular evolution of RNA

    Date:
    March 18, 2022
    Source:
    University of Tokyo
    Summary:
    Researchers have for the first time been able to create an RNA
    molecule that replicates, diversifies and develops complexity,
    following Darwinian evolution. This has provided empirical evidence
    that simple biological molecules can lead to the emergence of
    complex lifelike systems.



    FULL STORY ========================================================================== Researchers at the University of Tokyo have for the first time been
    able to create an RNA molecule that replicates, diversifies and develops complexity, following Darwinian evolution. This has provided the first empirical evidence that simple biological molecules can lead to the
    emergence of complex lifelike systems.


    ==========================================================================
    Life has many big questions, not least being where did we come from? Maybe you've seen the T-shirts with pictures going from ape to human (to tired
    office worker). But how about from simple molecule to complex cell to
    ape? For several decades, one hypothesis has been that RNA molecules
    (which are vital for cell functions) existed on primitive Earth,
    possibly with proteins and other biological molecules. Then around 4
    billion years ago, they started to self- replicate and develop from a
    simple single molecule into diverse complex molecules. This step-by-step
    change possibly eventually led to the emergence of life as we know it --
    a beautiful array of animals, plants, and everything in between.

    Although there have been many discussions about this theory, it has been difficult to physically create such RNA replication systems. However, in a study published in Nature Communications, Project Assistant Professor Ryo Mizuuchi and Professor Norikazu Ichihashi at the Graduate School of Arts
    and Sciences at the University of Tokyo, and their team, explain how they carried out a long-term RNA replication experiment in which they witnessed
    the transition from a chemical system towards biological complexity.

    The team was truly excited by what it saw. "We found that the single RNA species evolved into a complex replication system: a replicator network comprising five types of RNAs with diverse interactions, supporting the plausibility of a long-envisioned evolutionary transition scenario,"
    said Mizuuchi.

    Compared to previous empirical studies, this new result is novel because
    the team used a unique RNA replication system that can undergo Darwinian evolution, i.e., a self-perpetuating process of continuous change based on mutations and natural selection, which enabled different characteristics
    to emerge, and the ones that were adapted to the environment to survive.

    "Honestly, we initially doubted that such diverse RNAs could evolve and coexist," commented Mizuuchi. "In evolutionary biology, the 'competitive exclusion principle' states that more than one species cannot coexist if
    they are competing for the same resources. This means that the molecules
    must establish a way to use different resources one after another for
    sustained diversification. They are just molecules, so we wondered
    if it were possible for nonliving chemical species to spontaneously
    develop such innovation." So what next? According to Mizuuchi, "The
    simplicity of our molecular replication system, compared with biological organisms, allows us to examine evolutionary phenomena with unprecedented resolution. The evolution of complexity seen in our experiment is just
    the beginning. Many more events should occur towards the emergence of
    living systems." Of course, there are still many questions left to
    answer, but this research has provided further empirically based insight
    into a possible evolutionary route that an early RNA replicator may have
    taken on primitive Earth. As Mizuuchi said, "The results could be a clue
    to solving the ultimate question that human beings have been asking for thousands of years -- what are the origins of life?"

    ========================================================================== Story Source: Materials provided by University_of_Tokyo. Note: Content
    may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Mizuuchi, R., Furubayashi, T. & Ichihashi, N. Evolutionary
    transition
    from a single RNA replicator to a multiple replicator network. Nat
    Commun, 2022 DOI: 10.1038/s41467-022-29113-x ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220318080244.htm

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