Mitochondrial DNA, or mtDNA for short, is the DNA found in mitochondria, the part of your body’s cells that turns food back into life. Mitochondrial DNA is different than nuclear DNA (nuDNA), the kind at the centre of your cells, in at least three ways:
- All of it comes from your mother, none of it from your father.
- It is very short, making only 16 different proteins.
- It has no way to proofread itself to check for copy errors.
The last one means that mtDNA mutates or changes a hundred times faster than nuclear DNA. Most mutations are harmful and do not get passed on. But some are harmless and a few are even helpful. In mtDNA a harmless mutation takes place about once every 3,000 years.
In the late 1980s geneticist Allan Wilson tested the mtDNA of 137 people from different parts of the world. With that he built a family tree of mankind by assuming that those with fewer mutations between them were more closely related.
He was able to tell not only how man spread across the earth, but when (pictured above according to the latest numbers). By assuming one mutation every 3,000 years, mtDNA becomes like a clock that keeps time over tens of thousands of years.
In the 1980s many scientists believed in multiregional evolution: that humans, Homo sapiens, came from earlier manlike creatures not in one particular place but slowly all over the world. So the Chinese, for example, came from Peking Man (Homo erectus).
Wilson’s work overturned that. He showed that humans started in just one place: East Africa. From there they spread slowly across Africa and then across the whole earth – at the speed of one mile (1.6 km) a generation. This is called the Out of Africa hypothesis.
When humans got to Europe they did not mate with the earlier Neanderthals: they either wiped them out or pushed them aside. There is no known mtDNA from Neanderthals in any one alive. The Neanderthal, Peking Man and all the rest were dead ends, not our ancestors.
By looking at people’s mtDNA and working backwards you can tell that everyone alive today came from a single woman who lived in Africa about 200,000 years ago: Mitochondrial Eve.
A branch of the human family tree where everyone has roughly the same mtDNA is called a haplogroup. They are given letters: L, N, M, X, etc. The dark-skinned people in southern India, Australia, New Guinea and Melanesia, for example, belong to haplogroup M.
Most black Africans belong to haplogroup L, the same as Eve herself. There are seven main branches of it within Africa, named L0 through L6.
About half the people in Europe belong to haplogroup H. Its Eve has been called Helena. She lived in south-western France 20,000 years ago. By 28,000 years ago her ancestors were already in Europe. That is not good guesswork but a fact: we have the remains of a person called Paglicci 23 who lived in Italy 28,000 years ago that we can date and test.
– Abagond, 2010, 2016.
Update (2016): It is now known that at least some people from outside of Africa have some Neanderthal genes.
See also:
Abagond…this post is fantastic! I love it!
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L2 in the house.
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wow this interesting..
so if it comes from maternal.. then i must be L1.
Because my greatgrandma was from the area where ‘L1 is marked so she pass it to my grandma who pass it to my mother who pass it to me .
which in turn means I passed it to my sons and my daughter?
this is how it works right? 🙂
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well actually to look closer it is more L0 or L5
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Very interesting topic!
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Very eye opening.
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There are only two groups of people: those who left Africa at some point in time, and those who never did.
That’s why “race” as a biological category doesn’t make much sense. We all came from Africa, so to speak.
This hypothesis is pretty solid. What happened to the Neanderthals, on the other hand, not so much. We still have no clue what happened. Did we destroy them (making it first genocide in history), did we mate with them, but only our mtDNA survived? The question is still open.
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It’s worth making one observation on this article right now, before the old “Are blacks a genetic race?” debate heats up again.
Note that mitochondrial DNA is different from the kind of DNA that determines what your body looks like on two main points:
1) Mitochondria DNA is not a part of the nuclear DNA which determines how your body is made;
2) It mutates at a hugely faster rate than nuclear DNA, which is precisely why it’s useful in mapping human migration. In genetic race terms, what this means is that two people can have essentially the same nuclear DNA in “racial” terms but have completely different mitochondrial DNA.
I bring this up because ever since mDNA tracking has become feasible, it’s been popular among the educate-yourself-via-Google crowd to claim that mDNA tracking “proves” that biologically distinct human subspecies exist. Generally, this error is made because the people in question cannot distinguish between human DNA and mDNA. They see the three letters D, N and A and, primed by decades of bad sci-fi movies, immediately believe that anything associated with those letters must determine how our bodies are built.
mDNA, however, does not determine a single physical characteristic of your body.
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This is an excellent blog and breaks down what is in essence a complicated science. I think for the first time I am beginning to understand it…Thanks!!!
In creating the blog there is one piece which caught my eye. I am just being pernickity again ha ha
“The DARK-SKINNED people in… New Guinea and Melanesia, for example, belong to haplogroup M. Most BLACK people belong to haplogroup L, the same as Eve herself”.
And on a differnt tact, the use of languages and concepts like (‘Mitochondrial) Eve. Is not Eve a mythological figure pertainingto Hebraic/’Semetic’ tribes?
Then you had the huma figure of ‘Lucy’ a name denoting the cultural background of the archaeologist, but not say an Ethiopian name?
Nice one
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A good documentary to watch is “The Journey of Man” by Spencer Wells. He starts out in Africa where he believes human life began and more interesting he attempts to trace the steps of migration from there going to India, Siberia and far beyond. Also very interesting findings in regards to the aboriginals of Australia.
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Thanks James!!
I was not able to find this documentary or parts of it for viewing on the internet, can you assist here?
A good documentary that was shown in London England, only a few months ago on the BBC was ‘The Incredible Human Journey’
Details of the show etc can be seen here
http://en.wikipedia.org/wiki/The_Incredible_Human_Journey
And you can watch some of the parts on youtube. However because youtube breaks down the programme into many parts it can make it difficult to follow the sequence of all the shows
I think this link is the beginning of the very first programme
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“Regular” and mitochondrial DNA
Mitochondrial DNA is different than person’s “regular” DNA. You get your “regular” DNA from both of your parents; actually, your DNA is an unique combination of their DNA. This combination is your DNA and it defines your genes, including the ones which define how you look.
Mitochondrial DNA has nothing to do with it. You don’t get any from your father: you mother’s is simply copied to yours.
Mitochondria
Mitochondron is a cell organelle that, simply put, generate energy for the cell. Mitochondria have their own genome, their own DNA- which is not the same as person’s DNA. Like I already said, you get mitochondrial DNA from your mother, and it’s not combined with your father’s. Which means it stays the same. In theory.
Mutations
In reality, mutations happen. Regular DNA has a mechanism to check for mutations and ensure nothing unpredictable and harmful happens. Of course, it doesn’t work perfectly all the time- mutations happen with regular DNA, and most of them are harmful. Some are neutral. Some, however, are positive, in a way that help individual survive better. These positive mutations are rare, but they are one of the forces that make evolution possible.
Now, mitochondrial DNA doesn’t have a mechanism for preventing mutations. Which means it changes faster. So, while all the people get their mtDNA from their mother, and mother only, mtDNA is not the same with all the people on Earth.
Mitochondrial Eve
However, all human mtDNA point to a single female person who lived about 200 000 years ago, probably in East Africa. She might not be the first Homo Sapiens Sapiens, but every single human has mtdDNA which directly descended from hers. In other words, this person was everybody’s ancestor.
Once again, this has nothing to do with race. As Thaddeus pointed out, mtDNA has nothing to do with our main DNA, and doesn’t affect how we look. In fact, it doesn’t affect any of our genes.
Why different DNA?
There’s a theory about origin of mitochondria, still unproved, but interesting. According to it, mitochondria were completely separate organisms that were taken inside cells of other (equally primitive at the time) organisms, and stayed there. They carry their own DNA that is different than cell’s main DNA, which is also organism’s (or in this case, person’s) DNA.
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J, I usually don’t like to market for others and not receive my cut but, Netflix!
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Lucia:
Right, you only get it from your mother. So like with Oprah they used her mtDNA to trace her mother’s line all the way back to Liberia, to the Kpelle people, in fact, who have the very same mtDNA she does. That means her mother’s mother’s mothers…. etc had to come from there. It is the only way her mtDNA could be like that.
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Mira:
Right; it seems like mitochondria were once free living bacteria that became parasitic and has been passed down to us.
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Mira says…
She might not be the first Homo Sapiens Sapiens…
Change that to “almost certainly isn’t”.
The current thinking is that humanity passed through a near-extinction event some 200,000 years ago and “Eve” was one of the relatively few humans to survive. It’s the luck of the genetic drift that we’re all descended from her.
And I should also point out that this isn’t some sort of scientific confirmation that the biblical Eve in fact existed and thus an argument for creationism, as I’ve heard a few scientifically illiterate Christians say. There were indeed other humans back then. Eve’s descendents were just the most successful.
Otherwise and excellent, excellent brakdown, Mira!
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Thaddeus:
Good point: mtDNA does not affect your looks and has none of the genes that go to make up what we think of as race. It is just a bit of celullar plumbing.
Yet because it can be used as a tracking device to create maps like the one at top, it does enter into the whole question of race.
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Well, sure. Obviously. Race as a historically constructed thing, no doubt. It shows how certain population groups got lumped together at the time of Western European expansion.
What it doesn’t show is why they were lumped together.
Also, I have my doubts as to whether or not the mapping listed above doesn’t have some very euro-centered presumptions built into its data. Note that Europe has the largest selection of mitochondrial groupings. There is no good biological reason for that to occur, but I can think of SEVERAL scientifically-prejudiced reasons.
Remember that it’s ultimately a human being who decides if THIS set of mDNA is different enough from THAT set to warrant classification as a new lineage.
Also remember that in all probability, we have far more DNA data for Europe than for, say, subsaharan Africa.
Now, remember that most genetic scientists are not African and a disproportionate number of them are white.
Finally, remember that whites tend to think that all blacks are basically the same.
Does any of this suggest a possible hypothesis as to why Europe has 10 haplogroups and Africa only 2 and 2 further subsets…?
I’ll leave the statement of that hypotheses as an excercize for students… 😉
(Also, note that on that map, mDNA is only presented to about 8,000 years ago.)
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There was recently a white Jewish scientist who did a study on a group of Africans who claimed they had descended from Aaron, Moses brother. (Levites)
Of course Jewish people were quick to deny association saying that Jewish people never ventured into Subharan Africa.
Thanks to DNA testing, this Jewish scientist discovered that his DNA matched up with these African jews.
During the report, he said without hesitation, ” These people are my family”
It was amazing
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J said:
In creating the blog there is one piece which caught my eye. I am just being pernickity again ha ha
“The DARK-SKINNED people in… New Guinea and Melanesia, for example, belong to haplogroup M. Most BLACK people belong to haplogroup L, the same as Eve herself”.
Good point. I changed it to “black African”.
“And on a differnt tact, the use of languages and concepts like (‘Mitochondrial) Eve. Is not Eve a mythological figure pertainingto Hebraic/’Semetic’ tribes?”
Well, that one I am not going to change. Not only do scientists (or at least science writers) use it, but I would bet that over 99% of my readers know who Eve is. She is in both the Bible and the Koran. By calling Mitochondrial Eve “Eve” almost everyone knows just what I mean – and that is the purpose of language.
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Grena:
That is a beautiful story. I wish more people were like that.
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Thaddeus:
I agree: just looking at the map, Africa seems to be understudied. Especially since two-thirds of the history on that map took place in Africa.
On the other hand, the Bantu expansion of the last 3500 years may have wiped out much of that history. Except for the odd bog man or ice girl we have no way of knowing what haplogroups there were in the past that may have died out. So far all the people from the past that scientists have tested turn out to belong to one of the known haplogroups.
The map at top only shows the branches that are still alive and known.
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@Thaddeus:
You also made a good point about how it is white scientists for the most part who are making sense of the mtDNA data. There might be other possible readings that are not Eurocentric.
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Thanks Abagond…
You see were pernickty can get you…ha ha
I am not sure, if you understood the point I am alluding to, and if you did then please excuse my error
I only raised the points because:
1. The ‘dark skinned’ Melanesians are no different from ‘Black Africans’ in the context of race.
2. As for the use of language, it is usually political. The reason I am able to write this text in English is because of the rise of the British Empire spreading its language, as did other Empires in the past like the Greeks (and hence all Greek names for Egyptian Gods etc, and not the indigeneous terms).
At this present timeI cannot quite rememeber which scholar(s) talked about ‘language and liberation’ but that may well yet be another topic of discussion at another place and time
Thanks
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Thaddeus said:
“Also, I have my doubts as to whether or not the mapping listed above doesn’t have some very euro-centered presumptions built into its data. Note that Europe has the largest selection of mitochondrial groupings. There is no good biological reason for that to occur, but I can think of SEVERAL scientifically-prejudiced reasons.Also remember that in all probability, we have far more DNA data for Europe than for, say, subsaharan Africa.
Now, remember that most genetic scientists are not African and a disproportionate number of them are white.
Finally, remember that whites tend to think that all blacks are basically the same.
Does any of this suggest a possible hypothesis as to why Europe has 10 haplogroups and Africa only 2 and 2 further subsets…?
**************************
Now that I think about it…Why the h*ll does Africa and other parts have such a small number of halogroups but Europe has the most out of all areas of the world?
I can’t tell an English from a German from a Greek(w/o nitpicking) but I can tell a Dinka from a Wodaabe from a Ethiopan from a Maasai?
Since everyone started out in Africa, Africa logically would have the most genetic diversity.
http://www.bionews.org.uk/page_13795.asp
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I am not sure about the exact study, but sub Saharan African DNA has been taken enough to determine that the greatest diversity of DNA is between individuals are those in Africa. Africans are more closely related to individuals in other countries.
Which means that if the rest of the world died off except African, in time the adaptations of humans to their environment would occur again. All phenotypes are related to adaptation.
One can not say what Eve look like. I hardly doubt she would look much like any African today.
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That is my understanding too – that Africa has nearly all of the genes that you can find other parts of the world in addition to some others found only there; that there was not much mutation as mankind spread – just certain genes becoming more common in certain regions due to genetic drift.
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On the other hand, the Bantu expansion of the last 3500 years may have wiped out much of that history.
Interesting point, but unless the bantus set up concentration camps, not likely. Hell, native american haplogroups are all over the place and Europeans were probably more… thorough… in their conquest of the Americas than the Bantus were in conquering Africa.
And Hathor has a GREAT point: Africa should have the greatest number of haplogroups, given how we understand biology to work.
It’s hard to say what’s going on, but past history and current biases can definitely give us some hypotheses.
I bet Africa’s under-reported and that there’s a lot of “Hell, they all look the same to me” prjudice goin on.
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We know a lot more about the genes of Europeans than Africans simply because there are a lot of scientists in Europe who do research on these topics, whereas there aren’t in Africa. What little we know about the genetics of African populations was also discovered by European and North American scientists, and they are the ones who are going to do further research on Africans, because African science is not actually at the cutting edge of population genetics research.
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Yep. About what I figured.
But all this goes to highlight just how contingent all this research is on old structures of empire, neh?
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J and Thaddeus Blanchette,
Scientist have a hard time studying in certain places in African. Many have had to suspend study because of wars.
Although the results of study may be biased, using Africa as a source of study isn’t, Africa is a gold mine of undiscovered resources, fossils, languages and culture.
I must say I have seen Anthropologist theories change over my life time and feel that there is less Euro-centric bias. Biology and Physics have greatly effected the study of Anthropology.
I also feel that Black people are putting to much emphasis trying to link us more closely to the first humans than any one else.
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@ Mr Blanchette. Its a shame but not entirely surprising….
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I would like to say that the above J…is J-ust not me
Abagond…a site where names can be replicated could
be problematic..ha ha
Nice one
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Annaleisha,
What I mean by my comments is that a lot of what we understand to be “genetic proof” on race or such things is, in fact, also limited by the history of colonialism and today’s racism.
People should be very, very careful accepting any biodeterminist theories on race and ancestry, given that the historical track records of these has been so poor.
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Science trumps bible babble, once again!
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