DNA Testing Of Deep Ancestry 119
Randall Burns writes: "
Oxford Ancestors, founded by world-famous University of Oxford scientist
Bryan Sykes has announced the public availability of an inexpensive($US 180) service that will trace matrilineal ancestry using DNA tests. Applications include forensics, genealogy and research of history. Coverage includes a recent BBC story. The currently available test can trace matrilineal ancestry back to one of seven women who lived 150,000 years ago to which 99% of all people of European descent can trace their ancestry."
Leet Slashdotter Ancestry (Score:1)
Anyways, couldn't this information be used for discrimination by corportations and other entities? Or is the information only available to the person who requests it? I mean, what if someone was traced back to a Neanderthal who lived in the Great Rift Valley? Some people could mistake that as the person being African-American. Of course this doesn't happen easily, but it's a possibility the conspiracy theorists out there can ponder on.
--
Vote for mind21_98 this November
Interesting, kinda. (Score:2)
Hey Rob, Thanks for that tarball!
One of seven women? (Score:4)
Seriously, I don't see the point of this. When people want to trace their ancestry, they're mostly concerned with who their great great grandparents were and who their relatives were that lived during the Civil war, not 150,000 years ago. Yeah, it's cool, but nothing I'd pay $180 for.
I always wanted to know (Score:2)
On the other hand I can see how some people could be disapointed to find out that their great^n n->inf was some OOG who built the StoneWedge, or maybe even that their cousin's mother's brother's father's sister's daugter's
But the real question... (Score:3)
Similar project already started by BYU (Score:1)
Um.. Who? (Score:1)
In other news... (Score:1)
FluX
OOG YOUR ANCESTOR!!! (Score:3)
OOG WONDER HOW DARE YOU OVERLOOK YOUR HERITAGE!!! WHY YOU BE UNGRATEFUL BASTARD!!! IF NOT FOR OOG YOU NO HAVE SLASHDOT ACCOUNT WITH +1 BONUS!!! OOG DISSAPPOINTED IN YOU!!! AS OF TODAY OOG CUT YOU OUT OF INHERITANCE OF OOG FAMILY FORTUNE!!! OOG SUGGEST YOU SHOW MORE RESPECT TO CAVEMAN ANCESTOR!!! PERHAPS OOG ALSO SHOW YOU DISCIPLINE BY BREAK HEAD!!!
Re:Um.. Who? (Score:1)
Re:Um.. Who? (Score:1)
Um... I'd be surprised if they had names back then as we know them now. And I don't think the concept of biographies had been invented yet, either.
After 150,000 years ... (Score:1)
Great.... (Score:1)
Legality of these Tests in the business community (Score:2)
As far as being African-American. Unless you're planning on carrying a cross through your neighborhood in celebration of our happy little christian holiday on Sunday, you'll probably admit that life pretty much began in and about africa/fertile crescent. thusly - YES! we are all indeed African-American (or black as i like to say) in heritage. Damn - i'll bet that really pisses people in the KKK off....oh well, i guess now they'll just have to lynch themselves!
FluX
Evolution ? (Score:1)
But wait... (Score:2)
Re:Whores! (Score:2)
I can finally prove (Score:1)
http://theotherside.com/dvd/ [theotherside.com]
I Already Know My Ancestors (Score:2)
Personally, I am deeply offended that Slashdot does not recognize the validity of psychics. I mean, for only $4.99/min I discovered who my ancestors are, plus I found out that my g/f was possibly cheating on me and a long trip is in my future!
Now moderate this up before I pour hot grits down your pants, sailor!
DNA testing is getting cheaper (Score:2)
This makes me wonder just where that DNA info is going and how well it will be tracked. I know labs can screw up (remember your chem lab assistant - they are now doing this for a real living).
I once had a drug test when I was considering working for GTE in Florida and I got a call from the lab saying they had got the names on the covers mixed up and if I wouldn't mind, they would send me a new cover that I could sign my name on and they would put it with my sample. Yea Right. With DNA the results will be absolute because everyone knows everyones DNA is different.
Why does it matter? (Score:1)
This is interesting from genetic stand point, if for no other reason so it can shut up racists. Imagine testing them and saying something along the lines of "Well you're descended from a little European genetics and a lot of African." As long as they keep video tapes of their reactions I would be happy. Remeber it's not what you come from and what you've done. It's where you're going and what you're going to do.
Re:In other news... (Score:1)
Mitochonrial DNA (Score:1)
--// Hartsock
Re:Evolution ? (Score:1)
Re:Similar project already started by BYU (Score:1)
I could make some rude, sarcastic, and accurate statement about these motivations, but I have to give them the nod. While the means are questionable, the ends have benifited genetic research and has helped cure some diseases.
The research at Oxford, though, looks to be much more advanced. In the long run, it should yeild some very benificial results.
Re:Evolution ? (Score:1)
Re:I Already Know My Ancestors (Score:1)
Why single out Katz? (Score:2)
What separates you from an idiot? Not to troll, flame, or whatever, but inside you/me/he/they/us is about the same chances for genius, idiocy, murderers, parents, children, etc.
Fine, you don't like Katz, that's just a personal thing. But I really hope this was a thought out comment, and not an innate, subconscious thread of your personality...
-AS
Re:Whores! (Score:1)
--
Re:Why single out Katz? (Score:1)
Re:No way! (Score:1)
For instance it was shown using mitochondrial DNA studies that everyone can trace their ancestory to one women (believed to be from central africa I think). This didn't involve any of her actual DNA just comparisons among currently living DNA.
My guess is such a service, if it is real, is using similar techniques. Who these seven women are is probably unknown their existance is merely deduced from currently availible DNA. If it is indeed the same technique it means that it can only show maternal ancestory (they look in the mitochondrial DNA which can he inherited directly from the mother).
Re:One of seven women? (Score:1)
So its worse than than that. For $180 you get told that in fact you had an ancestor 180 years ago
Now that's a harem!!! (Score:3)
Gee, SEVEN women? Adam had quite a harem!!!
--
Re:Legality of these Tests in the business communi (Score:1)
Even though it was "illegal", as it is in America today, for companies to discriminate based on genetic information, it still happened. Genetic information was so easy to get, people litteraly leave their genetic information everywhere they go in the form of tissue that is continually being shed (hair, skin, etc...). Just as today, discrimination still occurs based on race and sex, even though its illegal, discrimination can still occur. I think that it is very likely that, as technology advances and allows tests to be performed on minimal tissue very cheaply, this kind of test will become quite common in the business world. As the main character in Gattica states, and I'm paraphrasing, "why spend all that money training an employee who will die 10 years later of a heart condition."
All I can say is that I hope I have a healthy DNA record, for my children's and children's-children's sake.
Spyky
Re:No way! (Score:1)
Katz and OOG (Score:2)
If we are his peers, we can judge him. But if we are truly his peers, we realize we are just like him at some level, and any judgements we can make are hollow, pointless, and empty. Of course, if we aren't his peers, we actually have very little basis on which to judge him, then.
I don't begrudge the OOGs or the Katzes, both are part and parcel of what
-AS
Re:Evolution ? (Score:1)
searching for Zen Koans and other assorted
goodies.
It went smething like this...the master looked at
a dog (there was some reason for this) and said
"He is happy"
the student said "but you are not a dog, you can't
know if he is happy"
The master replied "But you are not me, you can't
know that I don't know if he is happy"
-Steve
Re:Similar project already started by BYU (Score:1)
I took the service and . . . (Score:3)
[luke skywalker]
NOOOOOOOOOOOOooooooooo! ! ! ! !
;)
___
Probably....but.... (Score:1)
Re:Katz and OOG (Score:1)
It better be cheap.... (Score:1)
Sure, DNA tracing will give you mathematical probabilities about where/when a hypothetical ancestor lived--but no amount of "historical research" is going to find that person. We don't have DNA samples of "third peasant from the left, Duke of Chattinghamshire's feudal fifedom".
As an example, let's say I went in. They take my DNA.
First iteration: "You have a mother." Well DUH!
Second iteration: "Your mother had a mother." Interesting, I never would have guessed.
47th iteration: "You have a great-(repeat 44 times)-grandmother. Simple math (20 years/gen, 47 gens) tells us she lived 1000 years ago. 'Historical research' tells us this was the Middle Ages. Your neighbor Joe has a 83% chance of having the same ancestor." Can I get my $150 back?
--
Re:DNA testing is getting cheaper (Score:1)
> going and how well it will be tracked. I know
> labs can screw up
Heh labs screw up? never!
Reminds me of a story of a highly publicised case
in the 80s where a train wreck occured and the
Driver was tested for drugs after the crash. He
tested positive for marijuana and there was a huge
to do about it.
Later on it turned out that the lab that did the
tests wasn't actually doing drug tests. Turnes
out they had just been making up test results for
months (either due to lack of funding or because
they were incompetent and couldn't run the
equipment) - that story didn't make the major
press though.
> I once had a drug test when I was considering
> working for GTE in Florida
Heh I refuse to take a job that requires drug
testing. I don't want to work for someone who
can't respect that what I do on my private time
is my buisness, and my body chemistry is none of
their buisness.
(I read somewhere that drug testing falls into
the same catagory legally as a full body cavity
search...would you submit to one of those as a
condition of employment? I wouldn't)
The new factions: (Score:5)
(Scene opens with armored mercenary on horseback approaching a stone castle retrofitted out of the decaying hulk of the abandoned steel husk of an office building. Camera pans, giving audience a breathtaking view of the barren, wrecked skyline of a post-apocalyptic American metropolis.)
Guard (steel spear glinting as he shouts): "Halt! Who goes there? Know ye that this place be the realm of the descendents of Bertha the Bountiful. If thou be a son of Agnes the Prolific, begone from here, lest we slay thee!"
Mercenary: "Good soldier! Stay thine blade, for I, too am of the Tribe of Bertha!"
Guard (in stupid, low grunting Superbowl-commercial voice): "Whazzuuuuuuuuuuuuuuup!"
Mercenary pulls a flintlock pistol from his belt, cocks the hammer, and fires at Guard, killing him instantly. Audience cheers.
Guard (lacking the decency to just DIE): "Lo! I am sped! Dead am I! I am made as dust by the treacherous asp! Gone am I from this mortal coil! I am---"
Mercenary: "Why won't you DIE??!"
(Mercenary dismounts, then proceeds to kick Guard till he falls dead, and more importantly, silent. Audience cheers.)
Mercenary: Never underestimate the 1% descended from Jane Doe the Probably-Just-a-Rounding-Error-In-Our-Calculations !
Mercenary proceeds to singlehandedly storm the castle, raping and pillaging, stealing treasure, weapons, and office supplies.
I think the term "trace" is a little misleading. (Score:1)
Don't forget, as late as 1900 more than 3/4 of the American population were rural farmers or otherwise agrarian.(IIRC) Most of us can probably trace our roots to farmers and we probably don't have to go back very many generations before this is true. The farthest I can trace my last name unbroken is to Iowa, 1837. If I don't take the strict last name route I can go back to the early 1700s when the Scotch-Irish emigrated en masse from Northern Ireland to the states. Thus, I know that my ancestors were all farmers, they were likely farmers in Ireland and Scotland before that. I know they were at least literate when they came to America, but I have no knowledge of my family before that. Seeing as how for many, many generations most of the human population was agrarian, passed knowledge orally, and did not keep records, I don't see how this study is going to help people "trace" their ancestry.
I realize that that was not the only purpose of the study BTW, and that they likely made many worthwhile discoveries.
Re:The new factions: (Score:1)
Vik
Re:DNA testing is getting cheaper (Score:1)
?
Wow! Does Autralia not have any sort of constitution or a right to privacy? Are they volunteering or being ordered? And, if the government can just demand your bodily fluids, aren't you really just a slave.
God, I hope that this never happens in the US.
Re:One of seven women? (Score:3)
Not really. 150,000 years ago we could assume the lifespan for a woman was about 40-45 years on average. Let's assume one generation is 40 years. Now we know these seven women had kids. For this example, let's assume each woman had 2 kids in their lifetime - one male, one female.
So, from seven women we now have 14 children - 7 boys and 7 girls. Now, let's assume that only half of the 14 of the kids ever had kids of their own. Continue this pattern through 3750 generations (40 year lifespan into 150,000 years) and you come to a really big number. (Get this number by doing 3750^7. You come to something like 1.04284286499e+25.)
That's a lot of people.
-- Give him Head? Be a Beacon?
LOL (Score:2)
I like your sense of humor
-AS
I don't think this is the real OOG... (Score:1)
Two: OOG uses spaces in his name, not underscores. That one's actually probably more definitive evidence that this was an OOG-poser.
7 women from one clan (Score:3)
What use is it? (Score:1)
Re:I don't think this is the real OOG... (Score:1)
Re:DNA testing is getting cheaper (Score:1)
Interesting idea... (Score:3)
Furthermore, mitochondrial DNA tracing is far less specific, since barring mutations mitochondrial DNA is identical from generation to generation. In other words, you're not going to get accurate family lineage tracing this way. You can get into the general ballpark (tracing back to one of seven women 150,000 years ago, for example) but you can't be very exact.
I guess it would have important symbolic value, however, particularly among warring nations. It proves that, in a way, we're all brothers (and sisters too, of course). Now if only we could get a few certain groups in the world, who shall remain nameless, to get that through their skulls...
Re:No way! (Score:1)
Now if you bothered to read this article you'd see that it said:
Therefore this supports the theory that homosapians come out of Africa.
Re:Katz and OOG (Score:1)
Wow. (Score:2)
This strikes me much differently than what seems to be indicated by most of the posts here already.
This awes me. That we've actually scientifically confirmed that one little tribe (or the roots of 7 little tribes) managed to fight their way though what passed for life for them, and the end result has been a large chunk of modern civilization.
For some reason it takes something like this to make me feel the wonder of something that could have been logically surmised and proposed beforehand.
I mean, logically you know that if our civilization manages to survive, it implies that:
But when is the last time something made your mouth drop open and think seriously and deeply about things like the above? When is the last time something happened and made it feel real?
I hope I've adequately expressed how this story makes me feel :)
Re:Similar project already started by BYU (Score:1)
Anyway, I do understand the principle and motivations behind the geneology work they do. In fact my parents are serving a mission at a family history center in SLC where they do extensive database work, cataloging various geneology books. Their methods seem fine, their motivations are their own.
You made a number of inaccurate statements. First they don't (or can't, not sure which) do the extraction work until you have been dead at least 50 years or if your family says it's ok. Second the principle is not that you are suddenly mormon after you have received the baptism for the dead work. You are just given the opportunity to accept the religion in the after life. Thirdly, the posthumous work is not the primary task of temples. That is actually rather a minor part. Fourth, all religions are just cult's that made it big.
Growing up as I did and living the life I led I obviously have a different outlook than a non-mormon. I feel that in general the modern church is typically a good thing. They generally teach good behavior and they do an amazing amount of social work for their members. If you come upon hard times and you are mormon, you won't ever have to worry about where your next meal is coming from if you are willing to accept the help. This is a much better situation than any government run welfare program, IMO.
Shades of Babel? (Score:1)
Of course, my mother always believed that the [13|9|7] tribes at Babel were us and the aliens that populate the universe...and the sundering by language was more of a sundering from earth itself...who knows
Re:One of seven women? (Score:2)
No offence intended, but I hope math is not one of your stronger points. The figure 3750^7 corresponds to seven generations of 3750 children (all of whom reproduce). That's a lot of children.
Furthermore, if each woman had two children, half of whom lived to reproduce, then the population would in fact become EXTINCT in about 3 generations (depending on how many males and females are born.).
Fortunately for us, human women have tended to have more than 2 and less than 3750 children.
OOG (Score:2)
I'm saying we aren't really peers of Katz because we don't write anything of substance for the front page of Slashdot. Thus my previous point; if we were really his peers, we would be walking in his shoes and living in his space. Since we aren't everything we see and say is clouded by the fact that we are, essentially, outsiders looking in. If you really don't want to be his peer, that's your choice, not mine. I can call you anything I want, real, imaginary, fictional, or otherwise, and that's just my delusion and reality.
So judge him, as long as you're comfortable with the fact that other people will judge you similarly. I prefer to not judge, if possible, on the grounds that I don't want to be judged either. Because, in all the world, in all the situations and contexts, sometime, someplace, you too will be an idiot, annoying as hell, etc... and someone just like you will be saying that about you. It would bother me if someone were to believe things like that about me... so I avoid believing that of others.
Now what would happen if Katz had another identity, and it happened to be OOG? Or some other of the trolls? It could happen ^^
-AS
Hmmm. (Score:2)
So if those seven women were of the "modern" type at that remote period, then they must have lived in Africa, or barely possibly the Near East. In which cases you should be able to trace a lot more people than just Europeans to them.
--
"Damn! And just when Piranha was starting to turn the tide of negative PR!"
Re:Evolution ? (Score:1)
Here's wondering what Dr. Freud would have made of that statement.
--
"Damn! And just when Piranha was starting to turn the tide of negative PR!"
Science well established? (Score:2)
Actually, my latent Luddite tendencies make me somewhat skeptical of the science involved here.
The problem is, once you provide a tree-producing algorithm, it is going to output some tree, no matter what the input is. The validity of the tree depends as much on the input as it does on the algorithm.
To take a geek-oriented analogy, consider a simulated neural network. Given a network, it produces some output regardless of what input you give it. It can be out of bandwidth for what the network is supposed to categorize. It could even be an array of random numbers. It doesn't matter; the network is going to produce an output anyway.
So with DNA categorizing algorithms, at least according to the skeptical hemisphere of my brain. Maybe it gives you seven matriarchs; maybe thirteen; maybe only one. But it will give you something, no matter what the input was.
--
"Damn! And just when Piranha was starting to turn the tide of negative PR!"
Re:The new factions: (Score:1)
How many women disappeared because they only had male children or grand-children?
Re:I almost sold my DNA last semester! (Score:2)
Re:7 women from one clan (Score:2)
Seriously, I'd go for it. I know one line of my family back eight generations, but I don't even know my great-grandmother's maiden name. I suppose I should ask her sometime. I'd love to know my family history further back.
--Kevin
Re:One of seven women? (Score:2)
So after a bit of digging, I found some info on growth rates at the following URL:
http://www.census.gov/ipc/www/img/worldgr.gif
The numbers are above 1 percent per year for the years they actually have data on. I'll assume that because life just wasn't always so easy, a growth rate of
Starting with a population of 14 (with the silly assumption that there were seven guys to go with those seven women) and multiplying by 1.001^150,000, we get a population of 1.8102974241583444 * 10^66
Thats a lot of people. So, it certainly sounds plausible to me.
--
grappler
Re:The new factions: (Score:1)
It was, after all, mostly the males who went pillaging and raping.
Re:The new factions: (Score:1)
And, with supremest irony unperceived by 'is hignorant mind, leaving the world even more full of Berthaites than before.
--
"Damn! And just when Piranha was starting to turn the tide of negative PR!"
Geographic Distributions? (Score:2)
Does anyone know anything about this? Or geographic distributions of the three clans of Africa? Also, does anyone know how much more specific this could get? What would the time limit be? Is it always going to be 100k+, or might it eventually get down to like 25k?
Re:One of seven women? (Score:2)
You miss the point. Let's say that all of Europe descended from 26 women, not 7. What the finding of 7 (in the sample he's tested, which is not definitive) different types of mitochondria simply means that 7 were dominant and the existence of the other 19 (whose genes you may in fact share more of) cannot be confirmed by this methodology.
In other words, that "stamp" identifies the *dominant* traits you have from one person, where the dominant trait in question is just the one. You may have parts from other moms of Europe, just not ones that are uniquely identifiable by his methodology.
_Deirdre
Re:Legality of these Tests in the business communi (Score:1)
actually, no. Life began about 3.5-4 billion years ago.
ummm - so you actually know when life began in the Universe? holy shit! have you been on Charlie Rose??? let's not get into semantics here, pud! - you're Jeff K. [somethingawful.com] aren't you??
FluX
Re:Legality of these Tests in the business communi (Score:2)
Gattaca, the name was taken from the initials used for the base pairs of DNA.
The problem with the hypothesized Gattacan universe is that just because you have a gene doesn't mean it'll be expressed. For example, I have celiac disease [celiac.com], which is genetic. Of the studies done, one involved identical twins, where it was found that where one twin expressed the disease, there was a 70% chance the other did.
Another study (I've been looking for it again) was on Type I diabetes. Basically, the study demonstrated that if one a) had the gene, b) was given cow's milk prior to 9 months of age, and c) had the third bout of influenza prior to puberty, the gene would be expressed.
Thus, I believe we'll develop rulesets, given a person's genes, of how NOT to express undesirable traits.
Thus, I see the future not in eugenics (as Gattaca would have us believe) but rather in providing information on working around genetic issues. To me, that is a far more plausible (and pleasant, if somewhat regimented) future.
_Deirdre
matralinial only... (Score:1)
Re:No way! (Score:1)
I don't understand you (Score:1)
Clearly it's the same with people. If you were to say that there were only 2 people around 150,000 years ago, your figure of 1.8*10^66 would be only reduced to a seventh, so there would still be 'a lot of people'.
Of course its still wrong anyway, the formula for population growth isn't p = p0*r^t, its something more like p = p0*e^rt, or something like that (something with an 'e' I don't remember exactly)
Also, that number has nothing whatsoever to do with the number of people alive at any particular time, these women could have lived at different times, and probably had peers that were not represented in the European mtDNA pool. (It has nothing to do with the fathers ether)
Re: (Score:1)
The last single % probably comes from several diffrent women, or something. And as far as incest, you wouldn't notice any, since this only traces mitocondrial DNA, witch you only get from your mother. I don't know of any one who was developed in the wombs of two diffrent people
The Origin of the Ancestry Wars (Score:1)
Re:I Knew It ! (Score:1)
Hrm... I do really like Maruchan Ramen Noodels [google.com], witch is about the only thing I can make...
Re:Evolution ? (Score:2)
No.
Re:7 women from one clan (Score:1)
(which includes natalie portman) are probably descended from hot grits.
Just one problem with that... (Score:1)
So while you could use the Y-chromosome technique to track patrilinear descent of men, the technique is rather useless for women. And even if it could be used to track women, it has all the same problems that mitochondrial tracking does (namely, since it's basically identical from generation to generation, you still can't get specific with it).
There is one possible interesting use for this, though: it could be used to determine how many men were in this tribe with the seven women, and furthermore it could be used to track which men and which women mated. Just think of the fun the tabloids could have with that one: "Prehistoric sex scandal! OOG seen with mysterious "eighth woman!"
Re:7 women from one clan (Score:1)
No, the other 1% of europians
Re:No way! (Score:1)
Re:But the real question... (Score:1)
Re:One of seven women? (Score:2)
Re:all humans descended from the Negro (Score:2)
Re:I don't understand you (Score:2)
Obviously. Don't think I'm reading too much into my little calculation
All I was trying to do was show that there is no reason, mathematically speaking, why there couldn't have been just 7 women in Europe 150,000 years ago.
Clearly it's the same with people. If you were to say that there were only 2 people around 150,000 years ago, your figure of 1.8*10^66 would be only reduced to a seventh, so there would still be 'a lot of people'.
Again, I'm not trying to make any claims about what the population growth for humans is or was, or what the population is or was. My formula was far too simple for that.
Of course its still wrong anyway, the formula for population growth isn't p = p0*r^t, its something more like p = p0*e^rt, or something like that (something with an 'e' I don't remember exactly)
Well, of course it's wrong. But it could never be wrong for the reason you just gave above. The equations p=p0*r^t and p=p0*e^rt are both exponential curves, and exponential growth can be expressed in either form - it doesn't matter. An exponential curve always has the property that it's "doubling time" never changes, no matter where on the curve you look. This is true for both equations you gave. The only reason people use the e^rt form is that it is easier to integrate and differentiate.
--
grappler
Matrilineal Clans (Score:3)
The Oxford Ancestors Matriline service relies on mitochondrial DNA which doesn't mutate often enough to provide the fine matrilineal distinctions that would be required for different matrilines that have a common matrilineal ancestress as recently as the Pictish clans probably do. However, it is interesting that the legend of the Pictish clans sets their number at 7 -- which is the same number of matrilines Sykes says constitutes 99% of the indigenous Europeans.
Re:In other news... (Score:1)
Re:DNA testing is getting cheaper (Score:2)
Most DNS tests don't compare your DNA, they basicly weigh each of your chromosones and get a graph of their relative weights and thats considered "proof".
Re:No way! (Score:1)
Leakies indeed...
Re:Evolution ? (Score:1)
Proven false - by whom? Keep your pseudo Christian Science to yourself.
And they dont use carbon dating to determine genetic regression.
Which goes to prove... (Score:2)
-AP
Eerie. (Score:2)
Sigh.
---
Re:One of seven women? (Score:2)
Fact is, I still suck at math. Oh well.
-- Give him Head? Be a Beacon?
Major weaknesses in mitochondrial lineage tracing (Score:5)
First, some much simplified background (I have a degree in molecular biology): Mitochondria are self-reproducing organelles (= cell 'organs') that many people believe were once independent organisms that entered into a symbiotic relationship with a host cell, and eventually became utterly dependent on the cell. They now function as the primary site for the production of ATP, the main cellular fuel. There may be hundreds or thousands in a single cell
Mitochondria reproduce (to some degree) independently of the cell, and contain their own DNA. The DNA for everything else is in the nucleus (the cell's brain) but the mitochondria 'live' and reproduce in cytoplasm (cell body). When we breed, the nuclear DNA does the whole dance of meiosis/mitosis we learned in school, but the mitochondria fission like bacteria. Most (if not all) of the mitochondria is from the mother because a) the egg has thousands of times as much cytoplasm as the sperm; and b) after first contact with the egg, the sperm's mitochondria go into hyperdrive ("the acrosome reaction") and burn themselves out.
Now for the Original Contributions
1. In the billions of years of symbiosis since the development of eukaryotes, many genes that are useful or essential to the mitochondria have 'migrated' into the nucleus.
2. Though the mitchondrial 'support' genes are fairly cosistent from person to person, they aren't identical in everyone. Those genes only got to the nucleus by accident (mutation, adaptation by mitochondria to the available cell resources, etc) and therefore not all strains may be able to live in all people, or certain strains may enjoy a competititve advantage in a given person
3. Some individuals are known to have multiple strains of mitochondria, due to the various flukes and accidents of biological history. I know of no study that states that *most* humans have only one strain, and doubt its the case. It's actually a good idea to have multiple strains, since anything that kills (or impedes the reproduction of) a solo strain would kill (or prevent the reproduction of) its host. Multistrain individuals should be slightly hardier.
4. Mitochondria became part of the cell when we were single celled organisms. The mitochondrial DNA variation we measure is presumed to be 'nonessential' because mitochondria have very little DNA, and most of it was largely fixed long ago. We presume we're sorting mitochondria by 'eye color', but we may not be.
4) Mitochondria must adapt to their host as the host changes. A cow's mitochondria is much less similar to ours than you'd expect, considering that cows and men didn't diverge very long ago on a mitchondrial timescale.
5) Suppose a type mitochondria in a remote tribe requires the (nucleus) gene PII'ase. This is fine if the tribe all carries the (nuclear) gene for PII'ase. However, this mitochondrial line may die out when interbred because outside populations may not carry the gene PII'ase.
6) I can think of a dozen other mechanisms, but let's not go overboard.
Conclusion:
Mitochondria are subject to many of the evolutionary and selection pressures as independent bacteria, symbiotes, etc. the finding that there are seven major strains of mitochondria in modern man simply suggests that seven mitochondrial strains are widespread and well-adapted to the core genome of humans
It doesn't mean there were only seven 'original women'
It may mean that there were only seven (mitochondrially) *undemanding* women [ducks!] and the truth may be far more complicated. (lesser strains may coexist with the support of the major strains, etc.) and probably are.
Re:OOG YOUR ANCESTOR!!! (Score:2)