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Language: en
Loss is really common when we look um
you know through evolution. I mean you
know look at things that creatures that
are kind of marked by loss. One of my
favorite groups are snakes right?
>> Oh the legs.
>> Where are those legs?
>> Right. Well they became burrowing
creatures a whole lifestyle. So they
evolved from lizards right? So they
evolved from four-legged animals. But
you have this whole group of animals.
They just
>> ditched their legs. Right. Ditch their
ears too.
>> Oh geez.
>> No ears on snakes either. Right man. So,
um, yeah, loss is pretty common. At the
same time, they're pretty efficient.
>> Snakes are pretty efficient.
>> They just reduce themselves to a tube.
>> They're a tube. Yes. With great muscles,
>> but they've been doing a lot of
inventing.
>> Yeah.
>> Venomous snakes.
>> Venom. Yes.
>> Venomous snakes. And are have been
incredibly uh creative in the last 30 or
40 million years, inventing all sorts of
venom toxins to take down their prey.
And that's another example we see
throughout the animal kingdom.
Independent examples, right? You know
about spider venom. you know about bee
venom, you know about scorpion venom,
you know about you know uh venomous uh
jellyfish and stuff all independent
inventions
>> wow
>> of venom. So these are new molecules
that get invented, right? So this is
inventions going all the time, but that
helps those animals get their supper.
And that's a [clears throat] really
powerful force in evolution, right? It
this if you have a way to get your prey,
you have a way to get food, this is a
really this is like evolution almost in
uh fast forward.
>> So language for humans is like venom for
the other animals, [laughter] right? You
can cooperate and hunt.
>> Well, in our culture today, language is
very much like venom. Yeah. But I think
you're making that analogy. But yeah,
these are this is uh you know, venom is
a special power that these animals have
and it's vital to essentially their
their daily being. And you know,
language is something. Yeah, we came up
with walking on two legs and and
language.
>> Uh pretty big inventions. Could you take
embryionic hakee
and stick a needle in me, change a
instruction, and I now have fangs and
venom?
[snorts]
>> Yep. [laughter]
>> Oh, what? What?
>> Now, I'm gonna say in principle, I
wouldn't say it's impossible. It's
probably a little bit of knowledge that
we would need to build for. But when you
know the program for making teeth and we
know a lot about it and when you know
how you might be able to sort of modify
that a little bit to make an elongated
tooth with a with a central canal which
is a fang.
>> Okay. Then we could we could tweak that,
right?
>> Wow. So
>> and then you know I we know how to make
venom.
>> Wow. That's what I wanted to get into
man because making this this molecule
venom it is such a mysterious thing to
me. I was like how would that even come
about? Right. Oh, it's the general idea
here is this.
>> All these characteristics we're talking
about, all these creatures that
fascinate us, right? The instructions
for making them are in the DNA.
>> And that book has been blown wide open
to us, right?
>> So, let me ask you a question about that
then. That's I'm sorry to interrupt.
>> Oh, no. Go. Anytime.
>> Does every animal have all of the
instruction book? Is it or or is it
later animals have all of it because
they have everything that came earlier?
>> Oh, everybody's got their own
instruction book. Sometimes some
chapters have been torn out and left
behind. Okay. and some have some new
chapters.
>> So, but they have a lot of instructions
in common because they have they have
their animalness in common. They have a
lot of cell biology in common which even
is deeper than animals that they got
cell biology that's in common with fungi
and bacteria and plants and stuff like
that. Right?
>> So, there's there's some common parts of
the code book. There's some unique
parts. But that codebook which was again
not accessible to us in starting to
become accessible in the early 1980s and
then
>> today oh my goodness I mean you know the
speed and the cost involved is is now
almost trivial right where it used to be
you know too expensive or impossible. So
yeah, I mean we can we can look at any
animal. We are having a great time. We
are having a great time.
>> And um so what we do it's kind of it's
it's a lot of science is detective work,
right? You're playing hunches. You're
trying to look around. You're trying to
find those clues, etc. And kind of DNA
science these days is exactly detective
work. You're saying, I okay, I've got
this creature here that doesn't have
this capability. I got this creature
here that does have this capability. And
I'm looking around to try to figure out
what does it have that it doesn't have.
>> Right?
>> And if I compare, for example,
nonvenenomous
animals, take a lizard or something like
that, to venomous snakes or
nonvenenomous snakes to venomous snakes,
I can see exactly what's going on when I
look in the right place in the genome.
>> And that's telling us that what's
happened is again this co-option thing,
taking something that was used for some
other purpose and repurposing it. And so
what's basically happening is that
snakes are taking proteins that have
been used inside the body to do
something normal.
They're making them usually in
significant amounts in a gland
and putting them into prey through that
fang and they're putting sort of
abnormal amounts of of something either
the same or a modified protein into that
prey and usually disrupting one of two
things. And and things like venomous
snakes, they're either messing up blood
heasis like clotting and heart rate and
and blood pressure
>> or the nervous system. They're stopping
the nervous system. So, for example,
respiratory arrest.
>> So, how does this begin before I'm sure
it doesn't start out as full-blown fang
venom gland. So, they're so the
chemicals just being secreted in their
mouth and they bite and then
>> probably components of saliva. Yeah. And
imagine the way these animals were first
taken down their prey was they're biting
and holding on.
>> Yeah.
>> Now, biting and holding on is kind of
dangerous,
>> right? You can go for a bad ride and get
really roughed up. Yeah.
>> So, you can imagine the ability to
strike and then sit back while the prey
dies
>> is a little bit safer attack mode,
right? So, if you can deliver something
in your prey during that initial bite
>> that will subdue it.
>> Yeah.
>> Then there you go. And so,
>> we've got a lot of enzymes in our mouth.
We had a lot of enzymes in our saliva.
Okay. And so what what venom evolved
from was some basic capability of
having, you know, digestive enzymes and
things like this in our saliva. And
instead of just sort of those things
passively getting transferred during a
bite, uh through this modified tooth,
the fang, a a delivery apparatus evolved
that could deliver a more potent wallop
of that kind of stuff.
>> Wow.
So you can sort of feel that transition
from a bite, hold on with some kind of
weak saliva,
>> right,
>> to strike, sit back, very potent, venom
delivered and and let it do the job.
>> This sounds somewhat like what you
described earlier where you connect
>> genes, but now you're connecting the a
saliva gland to a tooth formation gland.
>> Yeah.
>> And now they become a single system of
venom.
>> Now that's that's an apparatus. Yeah.
that that that then does your job. And
when we look at the venom components and
these are these are fascinating sorts of
things and I I I got so many stories I
want I'm trying I'm running my head and
say which one should I really tell you?
>> Yeah.
>> But I'll tell you one that's that's
really striking that one of my students
is studying right now. So I don't know
the reputation Australian snakes have
right. We've probably heard Australia's
dangerous.
>> Yeah. I was as we're having this
conversation I was sitting here thinking
about the box jellyfish which is another
>> another one. Yeah. So on land they had a
couple snakes called brown snakes and
taipans. And uh they make me nervous.
Okay.
>> And I like snakes. And here's the deal.
>> Have you been bitten?
>> Uh I've been bitten by nonvenenomous
snakes. Yeah. I got an old buddy that uh
uh he had a great saying which was he
said there were two kinds of snake
enthusiasts. Those who' never been
bitten and those have been bitten a lot.
[laughter]
>> So there's no if that comes from. Yeah.
Because Okay. You can you can you can
piece that together [laughter]
anyway.
>> Oh, I get it.
>> Yeah. Yeah. So,
>> uh, taipans and brown snakes, they're
remarkably toxic. So, so you know, ounce
for ounce of their venom, one of the
most toxic things on the planet. What
have they done? And this is just to give
you a picture of what what's the
strategy of venom.
If you look at what their venom does to
the prey blood, you can watch it in a
test tube. It will clot like that.
>> Okay. What they've done is they've taken
two clotting proteins, proteins that we
normally use to clot our blood in
response to injury.
>> Yeah.
>> Packed them into the venom gland. They
inject them into prey and that blood
clots like that. [clears throat]
>> So, it's essentially a instantaneous
stroke and loss of blood pressure.
>> Prey down.
>> Wow. So they've taken proteins that are
used inside the body and then using them
kind of outside their own bodies onto
prey
>> and that's the strategy of the venom. So
you'd think venom wait what is this kind
of you know
>> special substance etc. No it's using
existing proteins
>> in a new way.
>> Wow.
>> Right. Yeah.
>> And you can see when you ha or when you
already have that protein that can clot
blood. It's just a matter of making more
of it and delivering it in a new way
into another creature in an unregulated
way. So that creature that creature
balances blood clotting very carefully.
You just overwhelm it and it clots
instantly.
>> Do the prey respond with evolutionary
changes to resistant venom.
>> Brilliant. It's it's an arms race out
there. It's an arms race out there. And
we see this all Yeah, we see this all
over the world.
>> When prey are being prayed upon by
venomous creatures, they're evolving all
sorts of mechanisms. Some of those are
well they're all sorts of levels. So the
targets of the venom toxins are
evolving. There's a lot of pressure,
right? Because if you can be less
susceptible, then that means maybe you
you got better chance of surviving a
bite
>> or a bite that's sublethal is not as
>> hazardous, you know, that sort of thing.
>> It's going on all it's remarkable. So
this is the the joy to an evolutionary
biologist or you might say the purpose
to an evolutionary biologist is studying
this is that those arms races going on
meaning the the there's pressure for the
predator for the for the venomous animal
to keep coming up with more and more
potent venom and there's pressure for
the prey to keep coming up with ways to
evade that venom. So you sort of have
evolution in fast motion going on in
both sides and that allows us to to it
it makes the evolutionary process sort
of we just have more stuff we can dig
into when it's when it's happening on
that kind of time scale. So it's
measured countermeasured that's why we
call we refer to them as as arms races
obviously from from the human analogy.
>> It it's all over the place. You go out
west
>> there are you know rodents that are you
know resistant to rattlesnakes. There
are snakes that feed on rattlesnakes
that are resistant to rattlesnakes.
>> Oh yeah. So here here's a question. So
when we develop antivenenoms from the
movies I've watched.
>> Yeah. [laughter]
>> They we typically make the antivenenom
from the venom.
>> Yes.
>> Do we ever use the praise mechanism to
create antivenenom?
>> God, you got great questions. Nobody's
done it yet, but I think that's the I
think that's the new opportunity now
that we've learned enough. This is
actually something my lab works on. Now
as we learn enough about the natural
defense mechanisms yeah we can exploit
them. So what we did this antivenenoms
got started in the late 19th century at
the same time we were making like
antitoxins for for things like dtheria
toxin and tetanus toxin and stuff and
what we do is we would immunize an
animal like a horse
>> with these toxins or venoms take the
blood of that horse we'd refine it and
that would be the product we would give
people who if they had tetanas or if
they got bitten by a snake. Okay. So
that's a 19th century. So you're using
that animal's immune system that has
been exposed.
>> That's right. That's right. And given
that um [clears throat] and you know we
use antibodies today, I mean you know
half the drugs that we use today are
monocone antibodies that we make in a
lab that we give people for everything
from cancer to eczema or whatever that
sort of thing.
>> But these natural defense mechanisms,
some of them look really to me they look
really really potent and broadly acting.
And I think I think there going to be
some antivenenoms coming out of this new
branch of knowledge from the from the
way that the prey defense mechanisms
work.