Hello,

We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not an Insider? Subscribe now for unlimited access to online articles.

Emerging Technology from the arXiv

A View from Emerging Technology from the arXiv

Why ET's genetic code could be just like ours

A new thermodynamic analysis suggests that 10 of life’s 20 amino acids must be common throughout the cosmos

  • April 6, 2009


One of the great outstanding questions in biology involves the evolution of the genetic code and the fact it relies on 20 amino acids. How did this system evolve and why use 20 amino acids and not some other number? Today, Paul Higgs and Ralph Pudritz at McMaster University in Hamilton, Canada, put forward an answer which has profound implications for the nature of life on other planets.

We know that amino acids are common in our solar system and beyond. Various first experiments to recreate the conditions in the Earth’s early atmosphere have produced 10 of the amino acids found in proteins. Curiously, analyses of meteorite samples have found exactly these same 10 amino acids. Various researchers have noted this link but none have explained it.

Now we know why, say Higgs and Pudritz. They have ranked the amino acids found in proteins according to the thermodynamic likelihood of them forming. This turns out to match the observed abundances in meteorites and in early Earth simulations, more or less exactly.

That’s a neat piece of work. They go on to argue that the first genetic codes must have evolved to exploit these 10 prebiotic amino acids. The other amino acids which are all bigger and generally more difficult to synthesise must have been incorporated later. At any rate, Nature had settled on the full 20 we see today by the time the earliest common ancestor of all organisms on the planet first emerged, at least 3.5 billion years ago.

Higgs and Pudritz are not the first to suggest that the first genetic code consisted of 10 prebiotic amino acids but all previous arguments have differed in various ways. What’s impressive about their argument is that it is underpinned by the powerful theoretical machinery of thermodynamics.

The implications of this are huge. Thermodynamic arguments are as valid on Earth as they are in interstellar gas clouds, where evidence of amino acids has already been seen. What’s the betting that these amino acids are the same as the prebiotic 10 that Higgs and Pudritz finger?

These same thermodynamic arguments should also hold on Earth-like planets elsewhere in the cosmos. And if that’s the case, then ET may not be so alien after all, as Higgs and Pudritz imply with the extraordinary conclusion to their paper:

“The combined actions of thermodynamics and subsequent natural selection suggest that the genetic code we observe on the Earth today may have significant features in common with life throughout the cosmos.”


Wow!

Ref: arxiv.org/abs/0904.0402: A thermodynamic Basis for Prebiotic Amino Acid Synthesis and the Nature of the First Genetic Code

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus the digital magazine, extensive archive, ad-free web experience, and discounts to partner offerings and MIT Technology Review events.

    See details+

    What's Included

    Unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Bimonthly print magazine (6 issues per year)

    Bimonthly digital/PDF edition

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special interest publications

    Discount to MIT Technology Review events

    Special discounts to select partner offerings

    Ad-free web experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning print magazine, unlimited online access plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    What's Included

    Unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Bimonthly print magazine (6 issues per year)

  • Insider Online Only {! insider.prices.online !}*

    {! insider.display.menuOptionsLabel !}

    Unlimited online access including articles and video, plus The Download with the top tech stories delivered daily to your inbox.

    See details+

    What's Included

    Unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

/
You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.