
Dinosaur Feathers Found in Ancient Amber - mparramon
http://blogs.discovermagazine.com/d-brief/2013/09/20/dinosaur-feathers-found-in-ancient-amber/
======
sambeau
Archaeopteryx lived 150 million years ago, the feathers here (and proto-
feathers) are from 78 million or 79 million years ago.

So these are very modern Dinosaur feathers or feathers from proto-bird-like
creatures.

What is interesting here is probably the proto-feathers / fuzz which might
shed light on the evolution of feathers and whether late dinosaurs were fuzzy.

[http://news.sciencemag.org/paleontology/2011/09/dinofuzz-
fou...](http://news.sciencemag.org/paleontology/2011/09/dinofuzz-found-
canadian-amber)

~~~
einhverfr
It now looks like feathered dinosaurs were a lot more common than that though.
Virtually all of the raptors (velociraptor, utahraptor, etc) are assumed to be
feathered based on fossil evidence today. When I was in grade school the real
breakthroughs were in the area of evidence of warm-blooded dinosaurs. More
recently though, there have been a lot of breakthroughs suggesting feathers
were much earlier than we had previously thought.

~~~
sambeau
Indeed.

I think what I was trying to point out is that this doesn't add weight to
early dinosaurs being feathered. These feathers are from the same period as
Velociraptors.

It's cool, its fascinating and it's mind-blowing that some of these feathers
could be from Velociraptor-like creatures! It's also great science.

But I was guarding against people saying "proven: all dinosaurs had feathers"
which is the inevitable route that some of the internet commentary will take.

~~~
jonnathanson
Velociraptor almost definitely had feathers, as well as wings. In fact, it
pretty much _was_ a flightless proto-bird (though scientists believe it may
have descended from a flying predecessor). If it were alive today, we'd
basically see it as a curiously shaped, medium-to-large land bird with teeth.

Check out some of the post-2007 renderings of Velociraptor. My mind was
certainly blown, especially after having grown up with the image as portrayed
by _Jurassic Park_.

(2007 was when Velociraptor bones were discovered with quill knobs, almost
indisputably indicating that the animal had wings and feathers).

------
scoot
So not knowing anything about genomics / evolution - what advantage might
proto-feathers (and 'pre-proto-feathers' before them - if there is such a
thing) have conveyed that caused them to become full feathers? How does any
evolutionary advantageous feature get started?

~~~
lambda
For one thing, evolution can sometimes work by going through several stages,
of which the intermediate are not particularly useful but not harmful either.
By mere chance, they happen to last long enough for the actually useful
changes to build on top of them. For example, see Lenski's long term evolution
experiment with e. coli.[1] He's spent 25 years breeding several populations
of e. coli, and freezing samples every 500 generations or so (every 75 days).
After about 20 years, he discovered that one of the strains had evolved the
ability to metabolize citrate in an aerobic environment, which e. coli
normally can't do. Going back to the historical record, unfreezing some of the
past samples and repeating the experiment, he found that sample from after
generation 20,000 could re-evolve this trait, but clones from before that time
could not, indicating that there was a potentiating mutation that that
particular strain had had shortly before generation 20,000, which the other
samples did not have. Further evidence has shown that it may have actually
been two separate potentiation mutations.

Beyond that, however, proto feathers would have probably been useful for
insulation. They seem fairly similar to down feathers, which are great
insulators. Given the the feathers were also colorful, they may also have been
decorative, and used for catching the eye of potential mates.

1: [https://en.wikipedia.org/wiki/Escherichia_coli_long-
term_evo...](https://en.wikipedia.org/wiki/Escherichia_coli_long-
term_evolution_experiment)

~~~
andrewflnr
But we don't know that those potentiating mutations didn't have some kind of
benefit on their own, so that doesn't do much for the question of how proto-
feathers provide enough benefit to stick around and _spread_ long enough for
the next several million mutations to arrive and turn them into feathers. Is
insulation adequate for that?

~~~
lambda
If you take a look at the Lenski paper[1], it says:

> The potentiating mutations are not known to confer any phenotype amenable to
> screening, so there is no simple way to distinguish between potentiated and
> non-potentiated clones.

Now, that isn't conclusive evidence that there was no benefit on its own, but
it doesn't sound like there's any evidence that it did provide some kind of
greater fitness. It sounds like all evidence shows that the original mutation
didn't provide any particular phenotypic change on its own, it was only after
the later mutation that it had any measurable effect.

Now, with dinosaurs it's much harder to tell. We obviously can't do any kind
of controlled experiments, or observe them directly. But we can offer up a few
potential explanations. One is that some mutations can occur without either
helping or harming, but later on another mutation can lead to something
useful.

Or there may be benefits conferred by proto-feathers. Remember, in addition to
their similarity to down, proto-feathers are somewhat similar to hair, and may
provide many of the benefits that hair provides: warmth, colors which allow
either catching the attention of mates or blending in to the background,
better sense of touch (you can feel something before your skin brushes against
it), better sensation of the wind, and protection from things that may scrape
or cut you.

According to Wikipedia[2], the insulation and display (colorful feathers for
attracting mates) hypotheses seem to be the more probable. Obviously, we're
not going to solve this by speculating here on HN, and it may be that the
reason can never be conclusively determined because you can't go back in time
to run controlled experiments, but based on the evidence we have those
theories sound reasonably plausible.

[1]:
[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3461117/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3461117/)
[2]:
[https://en.wikipedia.org/wiki/Feathered_dinosaur#Primitive_f...](https://en.wikipedia.org/wiki/Feathered_dinosaur#Primitive_feather_types)

------
olalonde
One step closer to Jurassic Park.

------
pintglass
[http://www.imdb.com/title/tt0107290/](http://www.imdb.com/title/tt0107290/)

~~~
sambeau
DNA only lasts 10,000 years. They'd need a _lot_ of DNA from a single dinosaur
type to be able to stitch enough strands together to make one.

However… Mammoths!?

~~~
MarkTanamil
> DNA only lasts 10,000 years.

Source? Seems like an arbitrary number plucked out of somebodies ass.

~~~
sambeau
I got my information directly from a geneticist friend who was explaining why
cloning dinosaurs is not going to happen.

He may of course have been simplifying it for us.

Looking at the internet it looks like it's usually a lot lower. 10,000 years
is the longest it _might_ survive.

[http://www.slate.com/articles/health_and_science/explainer/2...](http://www.slate.com/articles/health_and_science/explainer/2013/02/dna_testing_richard_iii_how_long_does_dna_last.html)

This discussion explains it:

[http://science.slashdot.org/story/12/10/10/1754212/half-
life...](http://science.slashdot.org/story/12/10/10/1754212/half-life-of-dna-
is-521-years-jurassic-park-impossible-after-all)

 _" 10,000 years is roughly 20 half-life periods, so they should expect
roughly 1-millionth of the DNA to remain"_

EDIT: Reading on I see that if stored at cold temperatures it can last a lot
longer.

~~~
thaumasiotes
Honestly, if you're worried about your image the citation to slate isn't the
one I would have disclaimed.

That's quite some editorial comment at the end of the crev.info piece:

""" These claims should be remembered if ancient DNA older than that is
confirmed in future finds[...] if intact DNA is found in a dinosaur or other
fossil older than the upper limit they just stated, it could have the effect
of falsifying the evolutionary timescale. Since evolutionists are such staunch
believers, though, most likely the reaction will be, “Well, what do you know;
DNA can survive for 65 million years.” [...] The rest of us should remember
what they said beforehand about DNA’s upper limit age, and not let them get
away with it. """

Now we know -- if you've had result A for hundreds of years, and result B for
singles of years, then evidence suggesting that the two conflict clearly
supports result B.

EDIT: link to [http://crev.info/2013/07/longevity-of-dna-
estimated/](http://crev.info/2013/07/longevity-of-dna-estimated/) (and
vacillation about the propriety of citing to slate) was removed even before I
posted this reply. It seems to be a nice, on-topic summary of current
knowledge on the longevity of DNA, but wow, the editorializing. :/

~~~
sambeau
Ha.

I _really_ should have taken a second look at what I was citing! I removed
that before I saw your comment. For some reason I thought I'd cited some
interesting genetics blog. I read the paragraph. Yep. Took a quick look around
— looks science-y.

Oops. Bah. My shame. I spat my coffee out when I read the whole article.

On a related note, I really wish HN had a preview feature. I often end up
posting & _then_ editing because 1) no preview 2) sessions timing out.

