November 5, 2013 • 28 mins
Into the Hologenome... How can the bacterial fauna thriving inside our bodies influence evolution? Find out in this episode of Stuff to Blow Your Mind.
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind from how Stuff
Works dot com. Hey, wasn't the stuff to well your mind?
My name is Robert Lamb and I'm Julie Deklas, And
on this podcast we discussed a lot of topics that
get down to the heart of what we are, What
are we as human beings? And who is who is
(00:25):
the we in that sentence? Who is the I in
any different sentence? You know, we do a lot of
naval gazing, and we have a nice naval gaze only
topic for you today because it does get down to
the heart of what are we? What are we really
and and of the the hypothesis that we're looking at
in this episode hold true. Uh, the answer is is
(00:45):
far different than what we have thought, even in the
very recent past. Yeah, because we have talked about the
role of the microbiota in the past here, but now
we're gonna talk about something called the hola genome actually
just hollo genome um that furthert the idea that we
are all just sort of like skin wrappers and there's
a punch going on um that determines our biological and
(01:08):
in some ways are our mental fates um. And it's
not just genes here. So that's the big story with
the hologenium. Yes, and that skin wrapper description is pretty
accurate because when you get down to the cells in
our body, the gens and our body, it all adds
up to about ten of us. Yeah, because we're out
number ten to one by these bacterial cells. So there's
so much more going on um at the surface and below.
(01:31):
And in fact, there's this idea that evolution itself may
be driven by bacteria, which would make sense, I mean,
just on a very basic level, because again, ten percent,
only ten percent of us is us And that's a
ridiculous sentence to to make because then as we evolve,
then surely, I mean, then that other n has at
(01:51):
least some sort of voting rights, if not equal voting rights,
then at least some sort of voting rights. It would
just stand to reason, right, it would stand to reason.
But let's talk about what the micro biome, which is
made up of all this differing bacteria, has been up
to and do a quick little recap of the microbiome
project UM. This was funded by the National Institute of Health.
We're talking about two scientists, eighty institutions around the world
(02:13):
that sequenced the genetic material of bacteria, taking from two
d fifty people eleven thousand samples that came out of this,
and what we found out is that each human contains
up to eight million bacterial genes in contrast to just
twenty two thousand human genes. So again outnumbered, outnumbered. And
this is according to Michael Pollen in his article some
(02:36):
of My Best Friends are germs, he said that bacteria
can swap jeans and pieces of DNA with itself. This
is so crazy to me. Um he says, it's an
incredibly important adaptation that allows a microbiota which could be
exposed to a toxin or a new food, to swiftly
come up with precisely the right genes needed to fight
(02:57):
something or eat it. So we you've talked about this
is actually a lot in the past that the gut bacteria,
you know, without it, we just couldn't exist. It's breaking
down food for us. It's allowing us to get the
nutrients out of it and also to take the stuff
that's a little dicey in jettis in it. Yeah, and
at the very least we have an extremely symbiotic relationship
(03:19):
with all of this bacteria that in the same way
that that we depend on on fire and cooking to
externalize part of our digestion. We've also in effect brought
in outside workers to help with the with the digestion
of the food. So it's a so so Yeah, it
has this huge effect on our ability to actually consume
(03:39):
the nutrients we need to survive. Yeah. And we also
have talked about how newborns are slathered in a new
sort of microbiome for themselves via vaginal births, but it
turns out that the bacterial life of newborns are actually
seated before they're even ejected out into the world. Wow.
(04:00):
So even before they get to go through the birth
canal and just pick up all these new and exciting
bacteria to become a part of who they are, they
are they are already to use. Like a prior way
of of looking at it, you would say that they're
already infected, they're already tainted by the bacteria. But but
as we're discussing in this episode, it's it's wrong to
even think of it in terms of of of a
(04:21):
taint or a staining of the of the individual, because
there isn't really this pure, pristine individual. I mean, you
can do that. You can remove the micro biota from
a from an individual's member of a species, from an
individual organism, but with often dire results. Right. I think
the old view in the past was that any sort
of bacteria is bad. But now we've come from our
(04:42):
understanding of it, and it is really interesting to know
that a fetus is being seated via the placenta or
the cord blood, because you know that gives us this
idea that you cannot be separate from it, You cannot
be this pristine individual who is born completely germ free,
that this is part imparcel of us. In fact, Joseph
(05:04):
Knew he is a University of Florida pediatrician. He actually
examined the first stools out of infants that were just
born and found that yes, indeed, uh their guts had
been active and had been seated to create all these
different bacteria that he found in their stools. And he
said that we might provide mothers with a microbial cocktail.
(05:25):
This is his idea that it's so important that we
may be able in the in the future to give
mothers who are just dating some sort of microbial cocktail
that would really help to ensure that that infant was
born with the optimal bacterial profile. Wow. Yeah, I keep
coming back in my mind as of reading about this
topic to a new ship constructed in a shipyard. And
(05:49):
then when it's time to put that ship out the sea,
you can't just slide it out and let it float
off to nowhere. It's got to have a croup. It
has to have uh, individuals aboard the ship to make
it function, to to to make it seaworthy. And then
over time, of course you're gonna have rats and stow
aways living on it as well, or or you know,
luxurious passengers who don't actually contribute to the overall health
(06:12):
of the ship at least in any way. That that that,
you know, the people of shoveling coal would understand. But
but but certainly you have to have at least a
skeleton crew when it rolls out into the water. I
like that. I like that idea that I've got a
crew inside of me right now. Yeah, it's like you're
the starship Julie, and you have a certain um microbacterial
(06:33):
crew that is in effect kind of running the show.
I mean, with some certain you know, it's like the
Star Trek Enterprise there's a computer system that's doing other
stuff that you have the genes, you have, you have
the cells, but then you have also this rich, uh
diverse alien crew that is making everything function at optimal levels.
I was thinking more like I was a rap star
(06:55):
rolling in with your crew. Yeah, yeah, okay, well that's
good then, all right, so how could bacteria inform evolution?
Let's take a quick break, and when we get back
we will dive into that. All right, we're back, we are,
(07:17):
and we are going to talk about the case of
the parasitic wasp in order to get into this material
about gut bacteria specifically and how it might be driving sea.
But first, yes, we're talking about the process by which
news species evolved. When we've all seen seen trees of
of of different organisms of branching out, you have one
(07:39):
life form and then it ends up dirty into two
separate life forms and they stem from each other and
it becomes this grand tree of evolution spreading across millions
of years. But how does that break up occur? How
does how does that that divide happened between this species
and that. Yeah, and that's what we're going to get into,
and um, you know, we're what we are talking about
is a particular species, these that developed different genetic characteristics
(08:02):
to the point where they cannot mate with the original
species and producer fertile offspring. So a good example of
this are horses and donkeys. Right, they descended from a
common ancestor, but their genetic makeup diverged in their offspring.
A mule isn't fertile. So what I talk about in
Assonia wasps, Well, it turns out that there are four
very closely related species in it, and when these species interbreed,
(08:27):
they make what's called a hybrid. And sometimes these hybrids die.
So the question becomes why do hybrids die between closely
related species? And to try to answer this, Seth Bordenstein,
he's a co author of research on microbiota and speciation.
UM looked at these wasps and tested a hypothesis that
(08:49):
a new species of animal can arise through changes in
gut bacteria or the gut microbiome, which is amazing sort
of new lens to look at this whole idea of evolution. Yeah,
like his breakthrough here with that if you if you
remove the microbiome from the equation with these wasps, then
the hybrid offspring will survive to a certain extent, it
(09:12):
is supposed to just being doomed from the get go.
So it's showing that it's not just the genetics at play,
it's also the microbiomes of each species. So even though
they're it's kind of like with with two individuals, it's like, well,
they're physically compatible, but then they have no emotional compatibility,
you know, etcetera. There, you know, any number of examples
you can, you can, you can make up with people
(09:33):
where on one level everything lines up, but on another
more important level, they don't. And and here for these uh,
these two species to really successfully breed and produce a
viable offspring, not only did the genetics have to be
uh at least interlockable, but also the microbiome, which is,
you know, pretty big news because we're talking about the
diet and talking about the crew that occupies the ship
(09:56):
and uh, and you can't necessarily combine the cruise without
there being a lot of unrest. I think there's a
whole Battlestar Galactica episode about that. I think so. And
you know, let's talk about cruise rolling too, right, one
crew rolling against another Exactly, there's gonna be uh, there's
gonna be unrest, there's gonna be mischief, all right. So
this leads this idea of the holo genome. So what
(10:18):
is the hologenome. It's basically made up of um, you know,
within the organism a cell's mitochondria, the cells DNA along
with microbiota, and Richard Jefferson and Eugene Rosenberg they came
up with the description of this theory. And Rosenberg actually
stumbled upon a nine paper by Diane Dodge, who was
then a post doc at Yale University, and she found
(10:40):
that changing the diet of a fruit fly could alter
the flies mating choices after just two generations, which made
Rosenberg kind of scratched his head and wonder if he
could do the same thing in his lap. Yeah, So
basically his findings for it. If you take take this
single species, you split them into two different populations, you've
given each and individual diet, then the microbiome is going
to change, and eventually these individuals are going to they're
(11:03):
gonna no longer be compatible with each other. Yeah, that's right.
What they did is they took the single species that
they split and they give me two different types. They
brought them back together, and they found that they would
not mate with each other because they then had different
gut microbiomes. So that brings up this question of why
I kino as a vegetarian. If I start eating big Max,
(11:25):
is my husband going to back away from me because
you are both vegetarians. We're both vegetarians. If I change
my gut bacteria and I don't tell him, let's just
say let's throw that in the mix. For a week,
I eat this, I don't tell them, Um, you know
my gut microbiome changes, will he begin to sort of
find excuses, you know, to get out of the house.
(11:45):
I have a feeling that if you eat like a
big mac a day for a week after being a
vegetarian all this time, he's going to know, because because
your body is going to going to let everyone know
that there's a problem. Well, it's it's true. I think
that there would be some really big signs um, and
I won't go into what those signs might be. But
(12:06):
Seth Borden's team was was faced with this very same question,
what if what humans did this um with with the
same sort of thing happened, And he said, well, probably not,
but we do know that microbes affect the way we smell,
and and if individuals choose to date or find that
partners based on their smell, then that is a form
of discrimination that's occurring. If it happens to the population
or species level, the new species will be arising. So well,
(12:28):
anything is possible in biology. I doubt that humans will
be splitting into different species, yeah, because I mean the
other thing is that humans have a lot of additional
complexity layered on top of their smell related choices, So
they're not just going to necessarily be like, oh, well
she's she's really interesting and uh and I'm very attracted
to her, but uh, you know, she she eats a
(12:48):
little more garlic than I would like or or I'm
you know, I'm a true vegetarian and she's a what's
the what is it of your vegetarian? But he eat
eggs your ovo lacto edgetarian? You know, guess or you're
not vegan? Yeah, I guess. You know that. I can
imagine that their varying degrees to which people are hardcore
enough about their diet where it would be a problem.
(13:08):
But I mean, I know people. I know one person
who is you know, pretty hardcore vegan and her husband's
not and they seem to get along. Fine, it happens,
you're right, there are examples, yeah and there, and they
have a child, so they're not like two different species,
and they can they can actually breed, So there you go.
It's true. Alright. So yeah, with humans, it's not acting
honest at that level. But it's fascinating to see these flies,
(13:30):
essentially the same species diverging from each other just based
on the gut bacteria. Now, of course we should mention
holo genome theory is a theory, and it's one that
people like to fight about, especially with evolutionary biologists, who
are not necessarily on board in all cases with this theory,
with this new way of looking, because evolutionary theory is
all about competition, survival the fittest, right, And we'll have
(13:53):
more on that in a minute. But the reason I
mentioned it here is that I was looking at a
study of involving killer whales, and this is a a
study that was connected by Andrew Foot and evolutionary biologists
of the University of Copenhagen. Now why is he looking
at at killer whales because he's interested in uh, sympathetic speciation. Okay,
now this is the idea that you have the speciation
we're talking about two. You have one particular organism, one species,
(14:17):
and over time it diverges into two. And uh. Killer
whales have been a particular interest to people because of
sympathetic speciation. This is occurring without a geographic barrier. They're
in the same area, but there you have just a
two different groups of the same species engaging in different
diets and UH, and then different behaviors to pursue that
particular prey animal. And then eventually the argument is they're
(14:38):
going to become two different species. And we see that
to a certain extents happening already with killer whale populations
in the North Pacific and Antarctic, where you have multiple
genetically distinct populations. They haven't been formally described as separate species,
but they pray they have different prey prefaces. So one group,
one pack of killer whales, they are mammal eaters. They're
eating the seals and that's all they eat, so they
(15:00):
have specific patterns for hunting those seals that they pass down.
And then you have another group that eat fish and
they have specific patterns for for pursuing those prey, and
these two packs do not intermingle, and they have different
ways their their communication is even a little different. So
they're they're arguably well on their way to becoming two
different species. So, um, it's a it's a possible example
(15:23):
of of this, uh, this holo genome effect on sei. Yeah,
it's interesting that you bring that up because it does
kind of mixed sort of our our more traditional views
a speciation, which sometimes have to do with populations being
isolated or not being isolated or just geographically in different areas,
and how that might affect um the species, and then
(15:44):
you have the diet in that mix as well. Yeah,
now I want to I just want to mention this
is a two thousand and thirteen study just from August
and Food again as an evolution Biotyes, so he's not
pursuing this, uh, this holo genome theory as as an
explanation for what's happening with the killer whales. But but
I feel like it's a very strong possibility here because
we're looking at diet effects in a given population. Yeah,
(16:06):
so that's that makes a very interesting case there. Um, Well,
let's take another quick break and when we get back.
We are going to look more at the criticism leveled
here at the hologenae theory and how it might or
might not square with evolution. All right, we're back again.
(16:28):
We're talking about the holo genome. We're talking about looking
at the aggregate genome of an organism. We're looking at SELLS, mitochondria, sells, DNA, microbiome,
all of it together, and the to to basically constitute
the total genome of a particular organism. Yeah, in the
hologena Again, this is a very new concept. Um. You know,
Jefferson Rosenberg and to some degree Diane's do they all
(16:52):
contributed to this idea. Then you have Seth board and
seem really sort of trying to run with it a
bit more. Um. And I did want to point out
that Seth Boordenstein really engages people on this topic quite
a bit. He does this through his blog which is
called Symbiontisum, and he also does it through his Twitter
feed and hologeno hashtag hologenome of course, and I did
(17:15):
want to read a couple of things that he wrote.
Someone said, I'm not getting how hologenome is different than
co evolution systems with correlated inheritance, i e. Body lice,
and his his explanation was, because you can live without
parasites like lice, but you can't live without your microbiome.
So again he's making the case that this is part
(17:36):
imparcel of this sort of operating system that we have.
And just think back to Michael Pollan's example of how
some bacteria can swap d NA to respond to the environment. Yeah. Again,
the ship runs just fine without the rats, not so
much without the crew. Yeah. And you know, I was
thinking about this paired with epigenetics, and I will not
(17:56):
get into that, but you know, that's the idea that
you have this extra bit of information glommed on um
to your DNA, and you know, depending on what's going
on with the person's immune system or their external conditions
like famine for inst environment as their situation, uh, flipping
on or off individual games. Right, we're talking about generations
(18:18):
after that that are actually affected by that person's experience.
So nothing has cut and dried here. So back to evolution.
You know for us that has always seemed um, you know,
fairly straightforward at this point we're talking about variation, selection
and heredity. But now you do have this bacterial component,
or perhaps we have it, and I wanted to just
mention that there's there's one other little layer here in
(18:40):
the example of mice and how their brains develop, and
this is a two thousand and eleven experiment that showed
that mice need their gut flora for the brain to
really develop normally because germ free mice with no microbiotics,
ones that were removed showed severe deformities in their brain
structured and that ending hates that the brain and the
(19:01):
nervous system is dependent upon this proper gut microbiotic being
in place. Yeah, and that I mean that is obviously
huge because a lot of what we've talked about in
the past, just on the show, and a lot of
the information is generally out there. You know, it's easy
to get behind the idea, Oh, well, your gut back here.
It's good for you. It's good to have. It's good
to have around because it will help you digest, it
will help Yeah. Yeah, you know, you go on some
(19:23):
antibiotics for a U T I and then you you
end up taking a bunch of probiotics to sort of
balance the ship again. But but here we're seeing you know,
examples of severe brain deformities. So obviously it's not just
a matter of it's good to have, it's necessary to have. Yeah,
absolutely right. And then then the question is to what
(19:43):
extent is that you know inform other species of how
their brains and their gut bacteria work in tandem. So
again this gives us the idea that genes are not
the blueprint that we thought they were in the past.
And this is from science to point oh gerhard at him.
He said, whatever else we may think, it is clear
that viewing an organism and natural selection from the pure
(20:04):
perspective of genes is incomplete. Therefore, it may be more
precise to say that genes provide the basic environment, while
microbes manipulate and refined to produce a working ecosystem. As
a result, as goes their success, so goes ourship crew ownership.
But then you have someone like Andy Gardner of the
University of Oxford, and he sort of counterpoints us by saying,
(20:27):
I would be less inclined to bundle all these cells
together as a single integrated organism. And this is an
excellent point because sometimes the microbial cells will be doing
things that aren't good for the host. So yeah, we
see microbes in a new light in which we see
them in a more beneficial light. But it is true
that disease and illness are a result of bad bacteria,
(20:51):
not to call them bad or good, but yeah, but
of course the same thing can be said about genes,
that can be said about immune functions. There's it's a
it's a complicated chip, and there's a lot that can
go wrong, both in the hardware of the ship and
in the crew members, the stow aways, the rats, etcetera. Yeah,
and uh again, here we have boarding scene saying, look,
I don't know about this hologenome yet. Basically he's saying
(21:13):
dogma and linear thinking. It could also be wrong, but
a hypothesis is not wrong until tested. So it's out there.
It's out there for people's consideration. Um isn't going to
become the sort of you know, unified theory of everything
for the human body. We don't know, but I think
it definitely adds to the whole conversation of how our
bodies are actually responding to their environments, to their genetics,
(21:37):
to what we put in them. Yeah, and that's really
what these guys are pushing with the hologenome thing. And
they're not saying, all right, we have it. Here's the
answer to everything. They're saying, we think there's something to this.
We think this is a really important theory. We want
other people to explore this, uh in regards to other organisms,
other species, and of course the human body itself. You know,
I am participating in the u biome UM. This is
(21:59):
the sort A and UM science projects, and this week
I am shipping off my microbiotics samples. I can't wait,
going to get it back, going to find out what
my crew is doing there. Excellent, Ya in an envelope?
Is envelope? You just put it all in? UM? Yeah,
that's just basically it's just a couple of Q tips.
(22:20):
Now it's it's much more elaborate than that. And they
want to know obviously, like what your diet has consisted of,
and you report all of that along with the samples
that you provide. Excellent. Are you going to share the results?
I am yeah. Now, another criticism that some people level
with this is that it's just kind of a a
rehashed version of the Lamarchian model UM. And this, of course,
(22:41):
it goes back to nineteenth century Jean Baptiste Lamark, who
had this theory of evolution that incorporated the then popular
idea that organisms could pass on adaptive traits that they
acquired you're in their life times. The classic example of
this is a giraffe is trying to eat the leaves
of the top of the tree, restrains his neck, and
(23:02):
then the offspring that those giraffes have then has a
longer neck because the parent organisms strained their neck. It's
it's a little more involved than that, but it was
a popular theory for a while, and then came Darwin's
theory that is similar but a bit more nuanced and uh,
and then Lamarck faded into the background. It's true, although
(23:22):
Lamark has enjoyed a resurgence as of late. So you know,
to me, it's just reconsidering it, not reconsidering. You know,
evolution is saying, let's throughout the baby with the bathwater.
I think it's just saying what other things are going on? Yeah,
And I I also want to add that I think
understanding the hollo genome. Having a thorough understanding the halo
genome is of course what we're going to need if
(23:43):
we're gonna ever tell port people across the room or
across the planet, ordered another to another world. Right, because
because you've seen the fly, the whole deal there is oops,
he accidentally got his DNA splice with the fly d
n A and then monstrous consequences occur in Cronenberg's wonderful film.
And and even remember at an early age watching it
(24:04):
and knowing, well, you know, we have like, you know,
things living in our eyebrows, and then later on, well,
we have all these things living in our gut. And
then when you start looking at this, this this fact
that we are only ten percent of us, it really complicates.
You'd have to teleport not just this one organism, but
all of these organisms and have it all come out
on the other side completely intact and working order, without
(24:26):
any sailors, you know, stuck in sense in part of
the ship in the walls. It's right, you want you
want the ship to be fairly intact and not have
appendages sticking out. Ye now I'm drawing in other teleportation
sci fi films, but anyway, you get my point. It
really it complicates and changes what we think about, uh,
when we think about who we are. I just like
(24:48):
that I went to the place of you biom and
you went to that place. That's how it goes, right, Hey,
before we close out, let's call the robot over. We
haven't really been doing much listener mail, and then we
we try to make it up to him with a
whole epis so, but we really need to have regular
interaction with the robot if we if we want to
maintain a healthy relationship with our technology. Yeah, and put
that oil can away exactly all right. We heard a
(25:12):
lot from listeners on our Uncanny Music episode about the
science of uncanny music. Wind Is scary or creepy or weird?
Music have this effect on us? Is it cultural? Is
it's something in eight and uh, here's just one of
the responses. This is b from Boston Writing and says,
high blow your mind team, you're talking about why music
gives us chills? Brings to mind a little no neurological quirk.
(25:33):
There are plenty of people who, despite loving music and
feeling emotionally stirred by it, never experienced actual chills. I've
been a musician my whole life, but I always assumed
that when people said the music gave me chills, it
was a melodramatic figure of speech. I've been brought to
tears by music before and felt completely rocked by powerful passages,
but never once I've felt a tingle. It wasn't until
stumbling on articles about the phenomenon that I learned that
(25:55):
these claims of chills are real. Meanwhile, my boyfriend was
shocked to think that music could be experienced without these sensations.
Since this discovery, I've done a few impromptu surveys of
friends and co workers. In all of these environments, the
vast majority of people do get chills, but a steady
ten percent ish have shyly conceded that they have also
never felt them. The brain is a funny thing. I
(26:16):
have no idea what makes some of us chill haves
and have nots, but I would love to learn more
about it. Did you see anything about this side of
things in your research? Love the show and thanks for
all you do. Actually, they did not pop up in
the in our research, but it does make me want
to explore the chills as as a singular topic at
some point in the future. Like, really get into goose flesh,
(26:39):
really get into chill bumps, really get into pins and needles. Yeah,
I get pins and needles is different but it's the
still I think it's the same sensation, right, you're on
pins and needles, your your goose flesh, you're you're alert. Um.
It is a very interesting question as to why we
would all of a sudden look like chickens. Um. And
there's a lot more to it, obviously, they're there's some
(27:00):
holes in the research. People aren't exactly sure why. But
that's a good topic to cover and we've got so
many good emails about that that episode. Um. People send
us a lot of great links to two movies that
have been recut with scary music, like Mrs Doutfire, Yes, um,
Mary Poppins of course, Yes Poppins one where it turns
it into a horror film by just changing around the
(27:23):
music and the scenes, which is easy to do with
that movie because if you look at it now that
it actually you know, because it's like Foggio London, or
it has this sort of ominous feeling to it, just
in the tones of the great towns. Well. I love
the argument that she was actually a timelord, you know,
like the doctor doctor who Yes, um, so yeah, there
are many different ways to recast things given the boat
(27:44):
context of the music. All right, well, hey, if you
want to get in touch with this, you can find
us in a number of places. First and foremost, go
to stuff to Blow your Mind dot com. That is
our website. All the podcast show up there, all the
podcast not just the ones that are on iTunes, but
the backlog going back through the centuries, the hidden ones
and uh and then that's where we do our blog
posts or video show up there. Everything we do. That's
(28:06):
the mother ship. But you can also find us on
social media Facebook, we do a lot their Twitter, you
can find us there as well, Tumbler. We're always feeding
that thing, and of course you can find us on
YouTube as mind stuff ships. And if you want to
share your thoughts with us about today's episode or really
any other episodes, you can't always drop us a line
and you can do so. Blow the mind at discovery
dot com for more on this and thousands of other topics.
(28:34):
Does It How stuff works dot com
Welcome to Stuff to Blow Your Mind from how Stuff
Works dot com. Hey, wasn't the stuff to well your mind?
My name is Robert Lamb and I'm Julie Deklas, And
on this podcast we discussed a lot of topics that
get down to the heart of what we are, What
are we as human beings? And who is who is
(00:25):
the we in that sentence? Who is the I in
any different sentence? You know, we do a lot of
naval gazing, and we have a nice naval gaze only
topic for you today because it does get down to
the heart of what are we? What are we really
and and of the the hypothesis that we're looking at
in this episode hold true. Uh, the answer is is
(00:45):
far different than what we have thought, even in the
very recent past. Yeah, because we have talked about the
role of the microbiota in the past here, but now
we're gonna talk about something called the hola genome actually
just hollo genome um that furthert the idea that we
are all just sort of like skin wrappers and there's
a punch going on um that determines our biological and
(01:08):
in some ways are our mental fates um. And it's
not just genes here. So that's the big story with
the hologenium. Yes, and that skin wrapper description is pretty
accurate because when you get down to the cells in
our body, the gens and our body, it all adds
up to about ten of us. Yeah, because we're out
number ten to one by these bacterial cells. So there's
so much more going on um at the surface and below.
(01:31):
And in fact, there's this idea that evolution itself may
be driven by bacteria, which would make sense, I mean,
just on a very basic level, because again, ten percent,
only ten percent of us is us And that's a
ridiculous sentence to to make because then as we evolve,
then surely, I mean, then that other n has at
(01:51):
least some sort of voting rights, if not equal voting rights,
then at least some sort of voting rights. It would
just stand to reason, right, it would stand to reason.
But let's talk about what the micro biome, which is
made up of all this differing bacteria, has been up
to and do a quick little recap of the microbiome
project UM. This was funded by the National Institute of Health.
We're talking about two scientists, eighty institutions around the world
(02:13):
that sequenced the genetic material of bacteria, taking from two
d fifty people eleven thousand samples that came out of this,
and what we found out is that each human contains
up to eight million bacterial genes in contrast to just
twenty two thousand human genes. So again outnumbered, outnumbered. And
this is according to Michael Pollen in his article some
(02:36):
of My Best Friends are germs, he said that bacteria
can swap jeans and pieces of DNA with itself. This
is so crazy to me. Um he says, it's an
incredibly important adaptation that allows a microbiota which could be
exposed to a toxin or a new food, to swiftly
come up with precisely the right genes needed to fight
(02:57):
something or eat it. So we you've talked about this
is actually a lot in the past that the gut bacteria,
you know, without it, we just couldn't exist. It's breaking
down food for us. It's allowing us to get the
nutrients out of it and also to take the stuff
that's a little dicey in jettis in it. Yeah, and
at the very least we have an extremely symbiotic relationship
(03:19):
with all of this bacteria that in the same way
that that we depend on on fire and cooking to
externalize part of our digestion. We've also in effect brought
in outside workers to help with the with the digestion
of the food. So it's a so so Yeah, it
has this huge effect on our ability to actually consume
(03:39):
the nutrients we need to survive. Yeah. And we also
have talked about how newborns are slathered in a new
sort of microbiome for themselves via vaginal births, but it
turns out that the bacterial life of newborns are actually
seated before they're even ejected out into the world. Wow.
(04:00):
So even before they get to go through the birth
canal and just pick up all these new and exciting
bacteria to become a part of who they are, they
are they are already to use. Like a prior way
of of looking at it, you would say that they're
already infected, they're already tainted by the bacteria. But but
as we're discussing in this episode, it's it's wrong to
even think of it in terms of of of a
(04:21):
taint or a staining of the of the individual, because
there isn't really this pure, pristine individual. I mean, you
can do that. You can remove the micro biota from
a from an individual's member of a species, from an
individual organism, but with often dire results. Right. I think
the old view in the past was that any sort
of bacteria is bad. But now we've come from our
(04:42):
understanding of it, and it is really interesting to know
that a fetus is being seated via the placenta or
the cord blood, because you know that gives us this
idea that you cannot be separate from it, You cannot
be this pristine individual who is born completely germ free,
that this is part imparcel of us. In fact, Joseph
(05:04):
Knew he is a University of Florida pediatrician. He actually
examined the first stools out of infants that were just
born and found that yes, indeed, uh their guts had
been active and had been seated to create all these
different bacteria that he found in their stools. And he
said that we might provide mothers with a microbial cocktail.
(05:25):
This is his idea that it's so important that we
may be able in the in the future to give
mothers who are just dating some sort of microbial cocktail
that would really help to ensure that that infant was
born with the optimal bacterial profile. Wow. Yeah, I keep
coming back in my mind as of reading about this
topic to a new ship constructed in a shipyard. And
(05:49):
then when it's time to put that ship out the sea,
you can't just slide it out and let it float
off to nowhere. It's got to have a croup. It
has to have uh, individuals aboard the ship to make
it function, to to to make it seaworthy. And then
over time, of course you're gonna have rats and stow
aways living on it as well, or or you know,
luxurious passengers who don't actually contribute to the overall health
(06:12):
of the ship at least in any way. That that that,
you know, the people of shoveling coal would understand. But
but but certainly you have to have at least a
skeleton crew when it rolls out into the water. I
like that. I like that idea that I've got a
crew inside of me right now. Yeah, it's like you're
the starship Julie, and you have a certain um microbacterial
(06:33):
crew that is in effect kind of running the show.
I mean, with some certain you know, it's like the
Star Trek Enterprise there's a computer system that's doing other
stuff that you have the genes, you have, you have
the cells, but then you have also this rich, uh
diverse alien crew that is making everything function at optimal levels.
I was thinking more like I was a rap star
(06:55):
rolling in with your crew. Yeah, yeah, okay, well that's
good then, all right, so how could bacteria inform evolution?
Let's take a quick break, and when we get back
we will dive into that. All right, we're back, we are,
(07:17):
and we are going to talk about the case of
the parasitic wasp in order to get into this material
about gut bacteria specifically and how it might be driving sea.
But first, yes, we're talking about the process by which
news species evolved. When we've all seen seen trees of
of of different organisms of branching out, you have one
(07:39):
life form and then it ends up dirty into two
separate life forms and they stem from each other and
it becomes this grand tree of evolution spreading across millions
of years. But how does that break up occur? How
does how does that that divide happened between this species
and that. Yeah, and that's what we're going to get into,
and um, you know, we're what we are talking about
is a particular species, these that developed different genetic characteristics
(08:02):
to the point where they cannot mate with the original
species and producer fertile offspring. So a good example of
this are horses and donkeys. Right, they descended from a
common ancestor, but their genetic makeup diverged in their offspring.
A mule isn't fertile. So what I talk about in
Assonia wasps, Well, it turns out that there are four
very closely related species in it, and when these species interbreed,
(08:27):
they make what's called a hybrid. And sometimes these hybrids die.
So the question becomes why do hybrids die between closely
related species? And to try to answer this, Seth Bordenstein,
he's a co author of research on microbiota and speciation.
UM looked at these wasps and tested a hypothesis that
(08:49):
a new species of animal can arise through changes in
gut bacteria or the gut microbiome, which is amazing sort
of new lens to look at this whole idea of evolution. Yeah,
like his breakthrough here with that if you if you
remove the microbiome from the equation with these wasps, then
the hybrid offspring will survive to a certain extent, it
(09:12):
is supposed to just being doomed from the get go.
So it's showing that it's not just the genetics at play,
it's also the microbiomes of each species. So even though
they're it's kind of like with with two individuals, it's like, well,
they're physically compatible, but then they have no emotional compatibility,
you know, etcetera. There, you know, any number of examples
you can, you can, you can make up with people
(09:33):
where on one level everything lines up, but on another
more important level, they don't. And and here for these uh,
these two species to really successfully breed and produce a
viable offspring, not only did the genetics have to be
uh at least interlockable, but also the microbiome, which is,
you know, pretty big news because we're talking about the
diet and talking about the crew that occupies the ship
(09:56):
and uh, and you can't necessarily combine the cruise without
there being a lot of unrest. I think there's a
whole Battlestar Galactica episode about that. I think so. And
you know, let's talk about cruise rolling too, right, one
crew rolling against another Exactly, there's gonna be uh, there's
gonna be unrest, there's gonna be mischief, all right. So
this leads this idea of the holo genome. So what
(10:18):
is the hologenome. It's basically made up of um, you know,
within the organism a cell's mitochondria, the cells DNA along
with microbiota, and Richard Jefferson and Eugene Rosenberg they came
up with the description of this theory. And Rosenberg actually
stumbled upon a nine paper by Diane Dodge, who was
then a post doc at Yale University, and she found
(10:40):
that changing the diet of a fruit fly could alter
the flies mating choices after just two generations, which made
Rosenberg kind of scratched his head and wonder if he
could do the same thing in his lap. Yeah, So
basically his findings for it. If you take take this
single species, you split them into two different populations, you've
given each and individual diet, then the microbiome is going
to change, and eventually these individuals are going to they're
(11:03):
gonna no longer be compatible with each other. Yeah, that's right.
What they did is they took the single species that
they split and they give me two different types. They
brought them back together, and they found that they would
not mate with each other because they then had different
gut microbiomes. So that brings up this question of why
I kino as a vegetarian. If I start eating big Max,
(11:25):
is my husband going to back away from me because
you are both vegetarians. We're both vegetarians. If I change
my gut bacteria and I don't tell him, let's just
say let's throw that in the mix. For a week,
I eat this, I don't tell them, Um, you know
my gut microbiome changes, will he begin to sort of
find excuses, you know, to get out of the house.
(11:45):
I have a feeling that if you eat like a
big mac a day for a week after being a
vegetarian all this time, he's going to know, because because
your body is going to going to let everyone know
that there's a problem. Well, it's it's true. I think
that there would be some really big signs um, and
I won't go into what those signs might be. But
(12:06):
Seth Borden's team was was faced with this very same question,
what if what humans did this um with with the
same sort of thing happened, And he said, well, probably not,
but we do know that microbes affect the way we smell,
and and if individuals choose to date or find that
partners based on their smell, then that is a form
of discrimination that's occurring. If it happens to the population
or species level, the new species will be arising. So well,
(12:28):
anything is possible in biology. I doubt that humans will
be splitting into different species, yeah, because I mean the
other thing is that humans have a lot of additional
complexity layered on top of their smell related choices, So
they're not just going to necessarily be like, oh, well
she's she's really interesting and uh and I'm very attracted
to her, but uh, you know, she she eats a
(12:48):
little more garlic than I would like or or I'm
you know, I'm a true vegetarian and she's a what's
the what is it of your vegetarian? But he eat
eggs your ovo lacto edgetarian? You know, guess or you're
not vegan? Yeah, I guess. You know that. I can
imagine that their varying degrees to which people are hardcore
enough about their diet where it would be a problem.
(13:08):
But I mean, I know people. I know one person
who is you know, pretty hardcore vegan and her husband's
not and they seem to get along. Fine, it happens,
you're right, there are examples, yeah and there, and they
have a child, so they're not like two different species,
and they can they can actually breed, So there you go.
It's true. Alright. So yeah, with humans, it's not acting
honest at that level. But it's fascinating to see these flies,
(13:30):
essentially the same species diverging from each other just based
on the gut bacteria. Now, of course we should mention
holo genome theory is a theory, and it's one that
people like to fight about, especially with evolutionary biologists, who
are not necessarily on board in all cases with this theory,
with this new way of looking, because evolutionary theory is
all about competition, survival the fittest, right, And we'll have
(13:53):
more on that in a minute. But the reason I
mentioned it here is that I was looking at a
study of involving killer whales, and this is a a
study that was connected by Andrew Foot and evolutionary biologists
of the University of Copenhagen. Now why is he looking
at at killer whales because he's interested in uh, sympathetic speciation. Okay,
now this is the idea that you have the speciation
we're talking about two. You have one particular organism, one species,
(14:17):
and over time it diverges into two. And uh. Killer
whales have been a particular interest to people because of
sympathetic speciation. This is occurring without a geographic barrier. They're
in the same area, but there you have just a
two different groups of the same species engaging in different
diets and UH, and then different behaviors to pursue that
particular prey animal. And then eventually the argument is they're
(14:38):
going to become two different species. And we see that
to a certain extents happening already with killer whale populations
in the North Pacific and Antarctic, where you have multiple
genetically distinct populations. They haven't been formally described as separate species,
but they pray they have different prey prefaces. So one group,
one pack of killer whales, they are mammal eaters. They're
eating the seals and that's all they eat, so they
(15:00):
have specific patterns for hunting those seals that they pass down.
And then you have another group that eat fish and
they have specific patterns for for pursuing those prey, and
these two packs do not intermingle, and they have different
ways their their communication is even a little different. So
they're they're arguably well on their way to becoming two
different species. So, um, it's a it's a possible example
(15:23):
of of this, uh, this holo genome effect on sei. Yeah,
it's interesting that you bring that up because it does
kind of mixed sort of our our more traditional views
a speciation, which sometimes have to do with populations being
isolated or not being isolated or just geographically in different areas,
and how that might affect um the species, and then
(15:44):
you have the diet in that mix as well. Yeah,
now I want to I just want to mention this
is a two thousand and thirteen study just from August
and Food again as an evolution Biotyes, so he's not
pursuing this, uh, this holo genome theory as as an
explanation for what's happening with the killer whales. But but
I feel like it's a very strong possibility here because
we're looking at diet effects in a given population. Yeah,
(16:06):
so that's that makes a very interesting case there. Um, Well,
let's take another quick break and when we get back.
We are going to look more at the criticism leveled
here at the hologenae theory and how it might or
might not square with evolution. All right, we're back again.
(16:28):
We're talking about the holo genome. We're talking about looking
at the aggregate genome of an organism. We're looking at SELLS, mitochondria, sells, DNA, microbiome,
all of it together, and the to to basically constitute
the total genome of a particular organism. Yeah, in the
hologena Again, this is a very new concept. Um. You know,
Jefferson Rosenberg and to some degree Diane's do they all
(16:52):
contributed to this idea. Then you have Seth board and
seem really sort of trying to run with it a
bit more. Um. And I did want to point out
that Seth Boordenstein really engages people on this topic quite
a bit. He does this through his blog which is
called Symbiontisum, and he also does it through his Twitter
feed and hologeno hashtag hologenome of course, and I did
(17:15):
want to read a couple of things that he wrote.
Someone said, I'm not getting how hologenome is different than
co evolution systems with correlated inheritance, i e. Body lice,
and his his explanation was, because you can live without
parasites like lice, but you can't live without your microbiome.
So again he's making the case that this is part
(17:36):
imparcel of this sort of operating system that we have.
And just think back to Michael Pollan's example of how
some bacteria can swap d NA to respond to the environment. Yeah. Again,
the ship runs just fine without the rats, not so
much without the crew. Yeah. And you know, I was
thinking about this paired with epigenetics, and I will not
(17:56):
get into that, but you know, that's the idea that
you have this extra bit of information glommed on um
to your DNA, and you know, depending on what's going
on with the person's immune system or their external conditions
like famine for inst environment as their situation, uh, flipping
on or off individual games. Right, we're talking about generations
(18:18):
after that that are actually affected by that person's experience.
So nothing has cut and dried here. So back to evolution.
You know for us that has always seemed um, you know,
fairly straightforward at this point we're talking about variation, selection
and heredity. But now you do have this bacterial component,
or perhaps we have it, and I wanted to just
mention that there's there's one other little layer here in
(18:40):
the example of mice and how their brains develop, and
this is a two thousand and eleven experiment that showed
that mice need their gut flora for the brain to
really develop normally because germ free mice with no microbiotics,
ones that were removed showed severe deformities in their brain
structured and that ending hates that the brain and the
(19:01):
nervous system is dependent upon this proper gut microbiotic being
in place. Yeah, and that I mean that is obviously
huge because a lot of what we've talked about in
the past, just on the show, and a lot of
the information is generally out there. You know, it's easy
to get behind the idea, Oh, well, your gut back here.
It's good for you. It's good to have. It's good
to have around because it will help you digest, it
will help Yeah. Yeah, you know, you go on some
(19:23):
antibiotics for a U T I and then you you
end up taking a bunch of probiotics to sort of
balance the ship again. But but here we're seeing you know,
examples of severe brain deformities. So obviously it's not just
a matter of it's good to have, it's necessary to have. Yeah,
absolutely right. And then then the question is to what
(19:43):
extent is that you know inform other species of how
their brains and their gut bacteria work in tandem. So
again this gives us the idea that genes are not
the blueprint that we thought they were in the past.
And this is from science to point oh gerhard at him.
He said, whatever else we may think, it is clear
that viewing an organism and natural selection from the pure
(20:04):
perspective of genes is incomplete. Therefore, it may be more
precise to say that genes provide the basic environment, while
microbes manipulate and refined to produce a working ecosystem. As
a result, as goes their success, so goes ourship crew ownership.
But then you have someone like Andy Gardner of the
University of Oxford, and he sort of counterpoints us by saying,
(20:27):
I would be less inclined to bundle all these cells
together as a single integrated organism. And this is an
excellent point because sometimes the microbial cells will be doing
things that aren't good for the host. So yeah, we
see microbes in a new light in which we see
them in a more beneficial light. But it is true
that disease and illness are a result of bad bacteria,
(20:51):
not to call them bad or good, but yeah, but
of course the same thing can be said about genes,
that can be said about immune functions. There's it's a
it's a complicated chip, and there's a lot that can
go wrong, both in the hardware of the ship and
in the crew members, the stow aways, the rats, etcetera. Yeah,
and uh again, here we have boarding scene saying, look,
I don't know about this hologenome yet. Basically he's saying
(21:13):
dogma and linear thinking. It could also be wrong, but
a hypothesis is not wrong until tested. So it's out there.
It's out there for people's consideration. Um isn't going to
become the sort of you know, unified theory of everything
for the human body. We don't know, but I think
it definitely adds to the whole conversation of how our
bodies are actually responding to their environments, to their genetics,
(21:37):
to what we put in them. Yeah, and that's really
what these guys are pushing with the hologenome thing. And
they're not saying, all right, we have it. Here's the
answer to everything. They're saying, we think there's something to this.
We think this is a really important theory. We want
other people to explore this, uh in regards to other organisms,
other species, and of course the human body itself. You know,
I am participating in the u biome UM. This is
(21:59):
the sort A and UM science projects, and this week
I am shipping off my microbiotics samples. I can't wait,
going to get it back, going to find out what
my crew is doing there. Excellent, Ya in an envelope?
Is envelope? You just put it all in? UM? Yeah,
that's just basically it's just a couple of Q tips.
(22:20):
Now it's it's much more elaborate than that. And they
want to know obviously, like what your diet has consisted of,
and you report all of that along with the samples
that you provide. Excellent. Are you going to share the results?
I am yeah. Now, another criticism that some people level
with this is that it's just kind of a a
rehashed version of the Lamarchian model UM. And this, of course,
(22:41):
it goes back to nineteenth century Jean Baptiste Lamark, who
had this theory of evolution that incorporated the then popular
idea that organisms could pass on adaptive traits that they
acquired you're in their life times. The classic example of
this is a giraffe is trying to eat the leaves
of the top of the tree, restrains his neck, and
(23:02):
then the offspring that those giraffes have then has a
longer neck because the parent organisms strained their neck. It's
it's a little more involved than that, but it was
a popular theory for a while, and then came Darwin's
theory that is similar but a bit more nuanced and uh,
and then Lamarck faded into the background. It's true, although
(23:22):
Lamark has enjoyed a resurgence as of late. So you know,
to me, it's just reconsidering it, not reconsidering. You know,
evolution is saying, let's throughout the baby with the bathwater.
I think it's just saying what other things are going on? Yeah,
And I I also want to add that I think
understanding the hollo genome. Having a thorough understanding the halo
genome is of course what we're going to need if
(23:43):
we're gonna ever tell port people across the room or
across the planet, ordered another to another world. Right, because
because you've seen the fly, the whole deal there is oops,
he accidentally got his DNA splice with the fly d
n A and then monstrous consequences occur in Cronenberg's wonderful film.
And and even remember at an early age watching it
(24:04):
and knowing, well, you know, we have like, you know,
things living in our eyebrows, and then later on, well,
we have all these things living in our gut. And
then when you start looking at this, this this fact
that we are only ten percent of us, it really complicates.
You'd have to teleport not just this one organism, but
all of these organisms and have it all come out
on the other side completely intact and working order, without
(24:26):
any sailors, you know, stuck in sense in part of
the ship in the walls. It's right, you want you
want the ship to be fairly intact and not have
appendages sticking out. Ye now I'm drawing in other teleportation
sci fi films, but anyway, you get my point. It
really it complicates and changes what we think about, uh,
when we think about who we are. I just like
(24:48):
that I went to the place of you biom and
you went to that place. That's how it goes, right, Hey,
before we close out, let's call the robot over. We
haven't really been doing much listener mail, and then we
we try to make it up to him with a
whole epis so, but we really need to have regular
interaction with the robot if we if we want to
maintain a healthy relationship with our technology. Yeah, and put
that oil can away exactly all right. We heard a
(25:12):
lot from listeners on our Uncanny Music episode about the
science of uncanny music. Wind Is scary or creepy or weird?
Music have this effect on us? Is it cultural? Is
it's something in eight and uh, here's just one of
the responses. This is b from Boston Writing and says,
high blow your mind team, you're talking about why music
gives us chills? Brings to mind a little no neurological quirk.
(25:33):
There are plenty of people who, despite loving music and
feeling emotionally stirred by it, never experienced actual chills. I've
been a musician my whole life, but I always assumed
that when people said the music gave me chills, it
was a melodramatic figure of speech. I've been brought to
tears by music before and felt completely rocked by powerful passages,
but never once I've felt a tingle. It wasn't until
stumbling on articles about the phenomenon that I learned that
(25:55):
these claims of chills are real. Meanwhile, my boyfriend was
shocked to think that music could be experienced without these sensations.
Since this discovery, I've done a few impromptu surveys of
friends and co workers. In all of these environments, the
vast majority of people do get chills, but a steady
ten percent ish have shyly conceded that they have also
never felt them. The brain is a funny thing. I
(26:16):
have no idea what makes some of us chill haves
and have nots, but I would love to learn more
about it. Did you see anything about this side of
things in your research? Love the show and thanks for
all you do. Actually, they did not pop up in
the in our research, but it does make me want
to explore the chills as as a singular topic at
some point in the future. Like, really get into goose flesh,
(26:39):
really get into chill bumps, really get into pins and needles. Yeah,
I get pins and needles is different but it's the
still I think it's the same sensation, right, you're on
pins and needles, your your goose flesh, you're you're alert. Um.
It is a very interesting question as to why we
would all of a sudden look like chickens. Um. And
there's a lot more to it, obviously, they're there's some
(27:00):
holes in the research. People aren't exactly sure why. But
that's a good topic to cover and we've got so
many good emails about that that episode. Um. People send
us a lot of great links to two movies that
have been recut with scary music, like Mrs Doutfire, Yes, um,
Mary Poppins of course, Yes Poppins one where it turns
it into a horror film by just changing around the
(27:23):
music and the scenes, which is easy to do with
that movie because if you look at it now that
it actually you know, because it's like Foggio London, or
it has this sort of ominous feeling to it, just
in the tones of the great towns. Well. I love
the argument that she was actually a timelord, you know,
like the doctor doctor who Yes, um, so yeah, there
are many different ways to recast things given the boat
(27:44):
context of the music. All right, well, hey, if you
want to get in touch with this, you can find
us in a number of places. First and foremost, go
to stuff to Blow your Mind dot com. That is
our website. All the podcast show up there, all the
podcast not just the ones that are on iTunes, but
the backlog going back through the centuries, the hidden ones
and uh and then that's where we do our blog
posts or video show up there. Everything we do. That's
(28:06):
the mother ship. But you can also find us on
social media Facebook, we do a lot their Twitter, you
can find us there as well, Tumbler. We're always feeding
that thing, and of course you can find us on
YouTube as mind stuff ships. And if you want to
share your thoughts with us about today's episode or really
any other episodes, you can't always drop us a line
and you can do so. Blow the mind at discovery
dot com for more on this and thousands of other topics.
(28:34):
Does It How stuff works dot com
Stuff To Blow Your Mind News
Hosts And Creators
Robert Lamb
Joe McCormick
Popular Podcasts
United States of Kennedy
United States of Kennedy is a podcast about our cultural fascination with the Kennedy dynasty. Every week, hosts Lyra Smith and George Civeris go into one aspect of the Kennedy story.
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com