Mitochondrial Eve

There's something awe-inspiring about the prospect of a primordial mother figure. Scientists actually discovered such a woman - and her ghost resides in the genetics of every living human. In this episode, Julie and Robert get to know Mitochondrial Eve.

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Episode Transcript

Speaker 1 (00:03):
Welcome to Stuff to Blow your Mind from how Stuff
Works dot com. Hey, welcome to stuff to Blow your Mind.
My name is Robert Lamb and I'm Julie Tuglas. I'm
actually Eve. Oh really are you? You're channeling the primordial
mother inside You're getting in your DNA. Yes, it is

(00:25):
a true statement to say that I could be an
iteration of Eve. Not the Eve of the story, but
an Eve. Now who is he? We should probably refresh everyone,
especially those of you out there who can grow up
attending Christian Sunday School or Jewish or just immersed in
world myths. Eve, according to Christian and Hebraic and Islamic tradition,

(00:47):
was the first woman, right, Adam was created by man
out of dust, and then he's lonely. He evidently needs
a friend, someone to do things for him, and so
he ends up taking Adam's were about and turning it
into this woman Eve, which seems totally possible. Yeah, and
then YadA, YadA, YadA, she borrows an apple from a
snake and it's the downfall of man and then she

(01:08):
has to suffer through painful childbirth and he has to
get a job growing crops and it's just a big
said sob story of the rest of the book, but
the idea of this primordial mother figure. You see this
throughout different systems of belief, in different myths and different religions.
Eve herself her name comes from the Hebrew hallaw which
means life and life giving feminine power. And in the

(01:30):
Salmutic tradition of Jewish literature, you have another figure, Lilith
that shows up as the first wife of Adam, but
she refused to listen to him and didn't want to
obey him, and so she was transformed into a demon
who then becomes this enemy of feminine reproduction and a
destroyer of infants, so sort of an anti primordial mother figure.
Then there are other characters such as Kiamet, the chaotic

(01:51):
primordial ocean goddess of ancient Babylon. There's Astra, the semantic
mother goddess, and Greek mythology you have Pandora, the first woman,
who also got into some similar curiosity related. Yeah, in
Japanese mythology there's is an Armi no Mikoto, and then
in Hinduism there's Sarupa, the first woman, the daughter of Brahma,

(02:14):
and she's actually the female portion of Lord Brahma. She
is the counterpart to manage. Again, you see this idea
throughout because on one level it's an embodiment of this
idea of what female power is and the role females
have in human society. And then on the other hand,
we're fascinated by our origins. So we've always wondered where
we came from, what we're our beginnings and was there,

(02:36):
indeed a most distant ancestor we were to trace back
our lineage far enough, would we come to a definite beginning,
would we say, oh, well here here she is, here
he is. Well, you could never come back to the
absolute beginning, right, But we can do something here today
where we can blow ancestry dot Com away and is
thirty something minutes right by talking about this idea of

(03:00):
mitochondrial eve. Yes, this first woman. But we'll talk about
more about what first woman means and in a little bit.
But first, before we start talking about this mitochondrial eve
from whom we all sprang this idea of this, let's
talk about evolution and something called the multi regional hypothesis. Yes,

(03:21):
so multi regional hypothesis. This is the idea that human
beings didn't necessarily originate with one particular explosion of evolution,
but that this evolutionary explosion happened in several different places
in the same way. You know, you hear about major
inventions where oh, well, these guys invented the airplane at
the same time as the right brothers. People were just
headed this way. The idea that, well, evolution was headed

(03:44):
this way towards humans, and it just happened at several
different points across the globe. It's far from the popular
theory at this point. It's more the exception rather than
the rule. But prior to seven, this was the prevailing
idea that our predecessor, Homo erectus had left Africa two
million years ago and spread out around the entire world,
and then these different populations adapted to their new environments

(04:05):
by evolving into Homo sapiens, and although there was constant
gene flow and interbreeding between these different populations, that everybody
remained part of the same species. So they thought this
model was the best way to explain all of those
Homeorectus fossils that they kept finding throughout Africa, Eurasia, and Australia.
The most widely accepted model today though, is the recent

(04:28):
African origin of modern humans model, or also known as
the out of Africa model. It's also sometimes known as
the out of Africa to model. And this is why
this holds that Homo sapiens evolved in Africa and between
fifty six thousand and two hundred thousand years ago migrated
into these other lands. The reason some people call it
out of Africa two is that it involves a previous

(04:50):
African exodus by tribes of Homo erectus. So following the
scattering of the Homo sapiens, they eventually outlived the previous
Homo erectus excursion and become the dominent. And the explanations
for the older fossils discovered elsewhere are basically representing hominid
lineages that had since gone extinct a long time ago.

(05:12):
So the idea with the recent African origin of modern
humans model the out of Africa model, is that human
evolution explodes once and that explosion consumes the globe, as
opposed to numerous explosions. Right. So, and the reason why
we mentioned seven is because in January of seven, Rebecca can,
Mark stone King, and Alan Wilson published a paper in

(05:33):
nature that dropped a bombshell, this bombshell of the recent
African origin model on our evolutionary doorsteps, so to speak.
The researchers examined the mitochondrial DNA taken from one forty
seven people across all of today's major racial groups, and
the researchers found that the lineage of all people alive
today falls on one of two branches in humanities family tree.

(05:56):
One of these branches consists of nothing but African lineage.
The other continued into all other groups, including some African lineage.
So that was one revelation that they had, and I
should also say to that the two distinct branches they
discovered contained the mitochondrial DNA found in five populations Africa, Asia,

(06:16):
European populations, Australian and New Guinea. And they found that
in the branch that was not exclusively African, racial populations
often had more than one lineage. For example, one New
Guinea lineage finds its closest relative and a lineage present
in Asia, not New Guinea. So this is all new
information to them. But here's the kicker. All of the

(06:38):
lineages and both of the two branches can be traced
back to mitochondrial eve, everyone can trace back his or
her lineage back to a single common ancestor who lived
around two hundred thousand years ago in East Africa. Yeah,
it's pretty mind blowing. I mean, it's important to stress
that we are not talking about even the actual like, oh,

(07:01):
there was this single woman and she was made from
a rib kind of a thing or anything of the sort.
There were women before mitochondria eve. There were other women
at the same time. But just do the luck and
the way things fell together, statistically, she ends up being
the primordial mother figure for everyone that is alive today. Right,
she was an ordinary woman for that time who became

(07:21):
extraordinary because basically her genetic material is what actually survived. Right.
And there's this idea that the reason why her genes
subsisted while others died away is because of a theory
called evolutionary bottleneck. And this is a situation when a
large majority of a member of species suddenly die out,

(07:43):
bringing the species to the verge of extinction. So there
could be a major catastrophic event, there could be an earthquake,
some sort of special set of conditions that would whittle
the population down. So it's possible that after a few
generations that have experienced this catastrophic event, that the mitochondrial
DNA of other women died out. And we'll talk about

(08:05):
this in a moment in a little bit more detail,
But if a woman produces only male offspring, her minochondrial
DNA will not be passed down. Since children don't receive
mitochondrial DNA from their father. This means that while the
women's sons will have her minochondrial DNA, her grandchildren won't
in her line will be lost. But we know that
with mitochondrial eve this did not happen. Now, you mentioned

(08:28):
bottlenecking there earlier, and this is something I found particularly interesting,
just about the way populations change as humans expand out
in ancient times. Two thousand seven, Cambridge researchers were looking
at fifty three different human populations from around around the world,
and specifically they're looking at skull shapes and genetic diversity,
and they found that the farther the population was from Africa,

(08:50):
the less varied its genetic makeup. The reason being that
its humans spread out from the cradle civilization, their population
size is dropped, and as their population size is dropped,
that means less genetic diversity to go around. In other words,
if you were to migrate to this one area outside
of Africa and there's not it's a long trip, we're
going to die and there's a small group, you're going

(09:12):
to marry your cousin probably. And also nature is going
to select the strong, the individuals that are suited for
the new environments that are being encountered. Those are gonna
be the ones that are going to survive. But if
you were to have state in Africa, then you would
have many more people to choose from to create more
offspring with. So let's take a break and when we
come back we will talk a little more about it.

(09:38):
So mitochondria DNA, what's the difference here? Okay, So DNA,
located within the nucleus of each of your cells, determines
your eye color, your racial features, susceptibility to certain diseases,
and other defining characteristics. I think of it that way.
Mitochondrial DNA, on the other hand, contains codes for making
proteins and carrying out other proces. Tessays mitochondria undertake. And

(10:02):
this I wanted to talk about two because I think
it's very interesting to see how DNA is replicated in
the context of something like this when we're talking about
two hundred thousand years ago. DNA is very long linear molecule.
It's a coded version of how to make another copy
of you. Basically, it's your your blueprint. Right. It's composed

(10:22):
of four subunits A, C, G, and T, and the
sequence of those subunits that is basically the material that
defines the blueprint. If you took all the DNA out
of every cell in your body and you stretch it
and to end, it would reach from here to the
moon and back thousands of times. Okay. So now think
of copying the sequence and repeating it, and this incredibly

(10:45):
long sequence you would see every once in a while
a typo of sorts would occur, and that would account
for the variation that we find with d N A okay.
So another interesting note about DNA when you're thinking about
mitochondrial DNA. In mitochondrial eve, that DNA is then changed
once again once it's combined with another set of DNA. Right,

(11:05):
So when parents come together and they create offspring, they're
merging their DNA. Mitochondrial DNA, on the other hand, is
derived almost exclusively from your mother, and this is because
the egg of a female human contains lots of Mt
DNA mitochondrial DNA, while male sperm contains just a little
bit of mitochondria. And the reason for that is it

(11:27):
because it helps it propel it basically, it gets it
the energy, it propels it towards its race towards the
egg for fertilization, and once it enters the egg, that
mitochondria is destroyed after the sperm for Eliza's eggs, so
any traces of that mitochondrial DNA from the sperm gone.
The only thing left is the female mitochondria in that egg. Okay,

(11:49):
So that that's why mt DNA could be passed on
only from mother to my Well, it can be passed
onto the sun, but the sign can never pass it on, right,
So that's why it's so tenacious, is because only the
mother side of this actually survives and passes on. Right.
It's matrilineal, and it's easy to track, right, and it's
not as variable as d n A because it doesn't

(12:10):
have to go through these recombinations, right, It's just sort
of like this pure packet that gets passed down at
least on the female line. So that's why we have
this mitochondrial Eve. That's why these researchers said, Okay, we've
been looking at d NA, let's look at mitochondria and
see what sort of story it can tell us about
our own origins and why they can then track our

(12:33):
own lineage to this woman, to to mitochondrial eve who
provided the blueprint for us. And again, I just want
to go back and say that she was not the
only woman on earth living at this time there, As
you said, there were women before her after. She probably
didn't chat with snakes and eat strange fright, no more

(12:53):
than the rest of us to right right, But she
just gave us the little packet of life that all
of us haven't common, which comes to this whole point
that we've talked about before, that we are all related
and much more so than we have ever thought. Yeah,
and I think that's ultimately the beautiful thing about it.
I mean, we love the idea of there being an Eve,
or there being any of these primordial original women Pandora

(13:15):
or Satarupa, because it's the idea that is something that
we have in common with everyone. And that's what this
ultimately drives home, the story of human migration that at
least ancestrally speaking, we are all Africans, and ancestrally speaking,
a large portion of us are ancestrally Indian. These are
roots traced back through these migrations and really unitis as

(13:36):
as a species well, and it really sort of makes
the term race obsolete. And also, I want to read
this bit to you from an Ionine article. It's called
how mitochondrial Eve connected all humanity and rewrote human evolution.
They say, okay, this is a game of numbers, but
really interesting. So let's say that you were born in
and both of your parents were born in nineteen fifty,

(13:57):
and your four grandparents were born in nineteen twenty five,
your eight great grandparents in nineteen hundred, and so on
and so on and so on. In other words, your
number of ancestors doubles every twenty five years. Further back
in time you go. So if you take this back
just one thousand years, simple math demands that you have
well over because this is crazy. Five hundred billion ancestors

(14:20):
in a single generation, considering that there's fewer than seven
billion people on this planet, and even that is far
far more than any other point in human history. There's
something seriously wrong here. Okay, So this is where this
really gets interesting. In this article, they say, the solution,
of course, is that you don't have five hundred billion
distinct ancestors, but rather a much much smaller number of

(14:43):
ancestors reappear over and over again in your family tree.
So these are not doublegangers or anything. So instead of
lots of different proto humans evolving separately over millions of years,
the story of humanity is much shorter and much more
elegant and more interconnected than scientists had ever imagined. And
this is a quote from Joseph T. Chang, Douglas lt Road,

(15:07):
and Steve Olsen from their two thousand and four paper
on something called m R c A. They say, no
matter the languages we speak or the color of our skin,
we share ancestors who planted rice on the banks of
the Yanksoo, who first domesticated horses on the steps of
the Ukraine, who hunted giant sloths in the forest of
North and South America, and who labored to build the

(15:28):
great Pyramids of Cufu. And within two thousand years it
is likely that everyone on Earth will be descended from
most of us. It really widens what you can be
proud of you know, you can be like the Pyramids,
that was me. Yeah, it was me, giant sauce arrow, Arrow,
I had great ero skills. I have great Erroo skills,
probably encoded in my d n A. Seriously, it is

(15:50):
beautiful and I think it's something that we would all
do well to keep in mind as we get through
our daily lives and everything from observing how the next
he is behaving on the train to what's going on
the news around the world. You know. Yeah, we've talked
about this for this idea that we're all breathing these
same molecules that have existed for millions and millions of years,
and we're breathing each other's foot odor and that should
connected some level and make us feel closer to one another.

(16:13):
But really, this is this is extraordinary to know that
we are this much smaller pool that we all came
from that we originally thought of in terms of these
ancestors that appear over and over again, these patterns of
our lineage. There we go, Well, let's call the robot
over and let's do it. Just a quick listener mail here,
all right. We heard from a listener by the name

(16:33):
of Mike Mike right sentences, Hi, Robert and Jewling. Got
into your podcast last year and haven't stopped since. Great
stuff to accompany a run on the treadmill, a long
drive to work, or a road trip. Thanks for keeping
my brain occupied. I listened to your Contact Lenses of
the God's episode today and it reminded me very much
of a great anime called Dinno Coil, in which a
fictional Japanese city in the not too distant future has

(16:54):
been having fun introducing augmented reality into the world. The
story revolves around the happening so have a bunch of
kids with a R glasses augmented reality glasses and the
adventures they get into, especially since a lot of the
things they can do in the a R portion of
the world is considered illegal. For example, they are frequently
hunted by an oversized anti BUYERUS software that formats illegal

(17:16):
cyber information. In several episodes, students are seen typing on
entirely virtual keyboards, composing emails and messages, as well as
sending each other pop ups to bother them in class.
The strange thing, as you might imagine, is that only
people with a AIR glasses can see any of these things.
In the off chance that you're into Japanese animation, you
should check the show out. So there you go. The

(17:36):
Shain It is called Dinno Coil, and we also heard
from a listener by the name of Austin about it
as well, so it is apparently a fairly popular and
I don't know if I mentioned it in the article
or not. Some other science fiction properties that involve augmented
reality or an augmented reality contact lenses. William Gibson has
in a few different books that involved virtual light. Specifically,

(17:58):
Spook Country has a lot of with the concept, and
Fire upon the Beat by Vernon Vinge, which I've not read.
It's on my two read lists. Supposedly, highly advanced contact
lenses play a crucial role in that as well. Hey,
what do you think about Let us know if you
find this information as you know, Lightning and hopeful as
the rest of us do. Let us know. You can
find us on Facebook where our handle is stuff to

(18:20):
Blow your Mind, and you can find us on Twitter
where our handle is blow the Mind. And you can
always drop us online at blow the Mind at Discovery
dot com for more on this and thousands of other topics,
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