Scientists Pull RNA from a 14,000 Year-Old Wolf | SciShow News


[intro] In a new study published this week in the
journal PLOS Biology, molecular biologists describe something unbelievable: the sequence of the oldest RNA discovered
to date. This RNA is estimated to be a little over
fourteen thousand years old. Its very existence challenges the long-held belief that ancient RNA just
isn’t a thing. And it suggests there could be lots of RNA waiting to be discovered in ancient remains. Now, fourteen thousand years might not sound
that impressive. After all, a couple of years ago, scientists were able to sequence the entire
genome of a seven hundred thousand year-old horse. But that was DNA—the molecular blueprint
inside cells. And though DNA starts to break down when a
cell dies, under certain circumstances, it can be preserved
for thousands of years. RNA is thought to be much more temporary—and
that’s by design. One of its main jobs is to carry the instructions
written in DNA to the cell’s protein-making factories— a process which, ideally, is pretty quick. Once those instructions have been delivered, an army of enzymes goes after the RNA to break it down and get it out of the way. And because it’s chopped up so quickly, many researchers have long assumed there’s
no point to looking for RNA in samples that are hundreds or thousands of years old. Except, recent studies have suggested ancient
RNA may exist after all. So, the authors of the new study decided to
look for it in some exceptionally well-preserved canine
remains. Two of their samples were skins from wolves shot in Greenland in the 1800s and 1900s. The third was a sample of tissue from a “puppy” found in frozen Siberian soil which was carbon-dated
to around 14,000 years old. And amazingly, the researchers were able to find and determine
the sequences of RNAs from all three specimens. They could even tell what type of tissue they
sampled based on the RNA! The Siberian sample now has the honor of being the oldest RNA known to science by about nine
thousand years, and the oldest sequenced by over 13,000 years! And that’s especially exciting because RNA can tell us things that DNA can’t. For example, because it reflects what a cell is doing at
a given moment in time, it could reveal what conditions an organism
was experiencing when it died, and even hint at the cause of death in cases
where there’s no obvious physical trauma. There are also some viruses that lack DNA,
like HIV and influenza. These are super significant for modern medicine, so it’d be great to see how their sequences
have changed over time or identify their presence in an ancient body. But that’s basically impossible without
ancient RNA, because these viruses often don’t leave
any other trace in the archaeological record. But it remains to be seen whether ancient
RNA is actually all that common. The authors pointed out that this Siberian
sample was particularly well-preserved, and such
remains are quite rare. Still, they’re hopeful that there’s more
ancient RNA hidden in the frozen soils of places like Canada, Alaska, and Antarctica. And it doesn’t have to come from soft tissues. Bones, keratin, even plant seeds could potentially be untapped reservoirs for
millennia-old RNA. Speaking of big surprises from the past… Paleontologists announced this week that they’ve
unearthed a giant parrot in New Zealand— the first giant parrot known to science. Today, the biggest parrot in the world is
the kakapo, a nocturnal flightless species native to New
Zealand. You may have seen this bird having sex with
Stephen Fry’s camera man’s head. That’s why I know it mostly. They can weigh up to 3 kilograms, which is about twice the weight of the biggest
macaw. But that’s downright wee compared to Heracles
inexpectatus, the fossil parrot researchers described this
week in a paper in the journal Biology Letters. The fossil was found in rocks dated to the
Early Miocene Epoch, between nineteen and sixteen million years
ago. Still, unique features of those bones made
it clear they came from a member of the parrot branch
of the bird family tree. And the team was able to calculate weight
and height estimates based on the relationship between leg proportions and body size in birds. That math suggests this bird weighed a colossal
seven kilograms and stood about a meter tall. Of course, with just leg bones to work with, it’s hard to say much about this Herculean
parrot’s daily life. But at that size, it’s a safe bet that it
was flightless. And it was probably doing the same thing that
most enlarged birds on islands do: taking over unoccupied environmental niches. You see, evolution does weird things in isolation,
and one of them is to make small animals big. It’s a phenomenon known as insular gigantism. And the fossil record is full of examples
of birds that got big on islands: oversized ducks in Hawai’i, giant storks
in Indonesia, and the dodos of Mauritius, just to name a
few But New Zealand really takes the cake for
big bird diversity. It’s been home to giant geese, humongous
eagles, and the famous moas in addition to the world’s
biggest parrots. These birds were able to achieve such large
sizes because the islands were basically devoid
of the sizable predators and plant-eaters that lived on the mainland. So, in the diverse subtropical forest of Miocene
New Zealand, there would have been lots of open opportunities
for a big bird to take up browsing on vegetation, or perhaps step into other roles normally
filled by medium-sized mammals. Some have even speculated this parrot-zilla
may have eaten other parrots! But, there’s no actual evidence of that…
yet. Truth is, we won’t know what they ate or
how big they really got until we find more fossils. Such finds could also shed light on the birds’
relatives— researchers aren’t sure if Heracles is a
close cousin of the kakapo or a separate instance of gigantism in parrots. Either way, these jumbo parrots shake up what
we thought we knew about parrot evolution. And hopefully, more fossils will help us flesh out this unexpected
titan. Thanks for watching this episode of SciShow
News! And a special, giant thank you to you, SR
Foxley—today’s President of Space. Your continued support of this channel makes
a colossal difference. So does the support of all our patrons— so thanks, all of you! And if you’re not a patron, but you think what we do here is good and
would like to help us do it, you can learn more about joining our community
of supporters at Patreon.com/SciShow. [ outro ]