Name: 科學家從一匹14000年前的狼身上提取RNA - 科學秀新聞 (Scientists Pull RNA from a 14,000 Year-Old Wolf | SciShow News)
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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.

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.

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

a process which, ideally, is pretty quick.

Once those instructions have been delivered,

to break it down and get it out of the way.

many researchers have long assumed there's no point to looking for RNA in samples that

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.

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

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

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

And it doesn't have to come from soft tissues.

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—

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.

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

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

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.