We May Have Just Unlocked a Secret to How Life Started on Earth


This one’s real easy, you guys–super low
key, not really a big deal, it’s just this silly question that nobody’s really interested
in, it’s just like….how did life begin? Ok, obviously I’m joking. This is one of the biggest unanswered questions
in science today, and is the backbone of our burning questions about who we are, where
we come from, and if we’re alone out here. New research has now given us clues into how
exactly the fundamental molecular building blocks of life came together in the first
place. Because that’s the central question: in
the big puddly soup of pre-biotic earth–as in, earth before living organisms–how did
the perfect ingredients for life form, much less fuse together into something that stores
information and can replicate independently. A primer on how our living cell’s work:
A cell’s most important components are DNA, RNA and a ribosome. DNA codes for all of the essential information
about what the organism is and how it works, but it’s kept all safe and huddled away
in the nucleus. To take that information and make it into
actual stuff, like proteins, an enzyme called RNA polymerase copies sections of the DNA
and makes strands of RNA, which are a like one-sided version of DNA. These messenger RNA strands get sent to the
cell’s ribosome, where they’re converted into the proteins our cells need for survival. When scientists were first discovering all
this complex stuff, it became an even bigger question of how all this could have spontaneously
come together as a result of organic chemistry. To tackle this problem, some scientists suggested
that perhaps life as we know it now didn’t all spontaneously form at once exactly as
it is, it was probably a little simpler…maybe it was only RNA-based! This hypothetical situation is what we refer
to as the RNA world. But this track of thinking is based on the
idea that the self-replicating aspect of life is what formed first. And not everyone agrees. Some people think that metabolization, or
the ability to extract energy from your environment, must have come first, while a third camp thinks
that compartmentalisation must have come first, a primitive version of the different internal
pieces of a cell. These divisions in the scientific community
still survive, but as we’ve come to learn more about RNA and how it can behave, it’s
become clearer that it’s an essential part of the beginning of life, if not the first
thing that formed. This is because RNA can do a really exciting
thing. Not only can it contain information that it
can then replicate…but it can also fold itself up into shapes in which it can act
as an catalyst, influencing chemical reactions! When this was discovered, we realized it was
much more likely that RNA-based life could indeed have survived and replicated all on
its own…without the all the fancy add-ons we have today. So then we come down to the question again–how
did RNA form in the first place? Scientists have been on a quest to demonstrate
how all of RNA’s component parts could have spontaneously assembled, and new research
may just bring it all together. RNA is made up of the nucleic acids cytosine,
uracil, adenine, and guanine. A research team had shown a few years ago
that a set of five simple compounds could have given rise to cytosine and uracil with
nothing more than the addition of UV light, which there was plenty of on a primitive earth. A different team then showed a similarly easy
and plausible process for the formation of adenine and guanine from simple building block
elements. But no one had demonstrated that these two
separate reactions, producing all four RNA nucleic acids, could have occurred in the
same place at the same time…until now. A paper that came out in 2018 showed that
a simple set of molecules–oxygen, nitrogen, methane, ammonia, water, and hydrogen cyanide,
all of which would have been present on an early version of earth–could react to form
what we recognize as the uracil, adenine, guanine and cytosine. This work is the first experimental evidence
showing that the chemistry fits–these building blocks could have feasibly all come together
at the same time, in the same place, we saw it happen before our very eyes. There are still a couple of missing pieces
that we haven’t been able to recreate in the lab. For instance, how did each of the building
blocks come together to link them into the long chains that take them from nucleic acids
to actual RNA? And, keep in mind, while the RNA world is
the leading theory, there is some contention among scientists about the first inklings
of life on earth. Hopefully work like this will add to that
discussion, PLUS it does represent an unprecedented step forward in answering the most fundamental
of questions: how life began. For more on DNA and the craziness of life,
check out another video of mine here. Don’t forget to subscribe to Seeker for
all your genetic information questions, and thanks so much for watching

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