It’s a sad aspect of modern science that if you want to puncture the public consciousness on a particular topic, you’ve got to either pretend you’ve recreated life, or throw a press conference to announce wobbly arsenic-based results. It tends to over-shadow scientific endeavor which is important and earnestly presented in a non-egotistical manner. One big leap to understanding the possible origins of life came from Philipp Holliger’s lab last month, and as I’m more of a Nature guy than a Science guy it passed me (and the wider public) by.
RNA is DNA’s feisty side-kick (if you’re really sad like me). RNA is often deemed DNA’s “simpler cousin” but in reality it’s anything but. RNA is truly the handy-man of life; it pops up anywhere and everywhere, in the ribosome, during translation, transcription, and splicing - all pretty important cellular processes which keep you, me and all the rest of known biological life alive. There's a whole host of types of RNA also - tRNAs, mRNAs, snRNAs... it's pretty diverse and a relatively new area of exploration in molecular biology.
What’s also mightily impressive about RNA is that it is capable of being two things at once. RNA can act as an enzyme (a biological catalyst), in which case it is called a “ribozyme”- and it can also act as a repository of information, like DNA in our genomes. It’s this ability for a single macromolecule to straddle dual roles, along with its (when compared to DNA) chemical simplicity which lead to RNA being proposed as a possible precursor to DNA-based life. This is known as the “RNA World” hypothesis – a time about 4-billion old years ago when life as we know it consisted of bits of RNA floating about and interacting with each other.
What’s also mightily impressive about RNA is that it is capable of being two things at once. RNA can act as an enzyme (a biological catalyst), in which case it is called a “ribozyme”- and it can also act as a repository of information, like DNA in our genomes. It’s this ability for a single macromolecule to straddle dual roles, along with its (when compared to DNA) chemical simplicity which lead to RNA being proposed as a possible precursor to DNA-based life. This is known as the “RNA World” hypothesis – a time about 4-billion old years ago when life as we know it consisted of bits of RNA floating about and interacting with each other.
Underpinning the RNA World theory is the assumption that RNA would need to be self-replicating at one point – allowing natural selection to kick in and allowing the eventual boot up of Life 1.0. An important step in the RNA World theory would be the production of a polymerase. These are enzymes which act like replicators, accurately copying other RNAs, allowing them to multiply and flourish (and evolve).
What Phillip Holliger’s lab produced was a RNA molecule called tc19Z capable of reproducing other RNAs up to 95 bases long with an accuracy of about 1 in 250 bases copied being incorrect. What’s even more impressive is that tc19Z is capable of replicating functional ribozymes. One such ribozyme is the hammerhead ribozyme, a quasi-suicidal self-destroying RNA molecule.
At 198 bases, tc19Z isn't far from replicating itself. Here's hoping that discovery punctures the public's consciousness a little more deeply.
At 198 bases, tc19Z isn't far from replicating itself. Here's hoping that discovery punctures the public's consciousness a little more deeply.
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