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Biotech Science

Humanity's Genetic Diversity on the Decline 285

Posted by CmdrTaco
from the meanwhile-my-beer-gut-it-on-the-incline dept.
jd writes "In a study covering five different periods of history, from 300 AD to the present day, and geographically spread across much of Europe, scientists have extracted the mitochondrial DNA from a sizable number of individuals in an effort to examine changes in diversity. The results, published in the Royal Society journal is intriguing to say the least. 1700 years ago, three out of every four individuals belonged to a different haplotype. In modern Europe, the number is only one in three. The researchers blame a combination of plague, selection of dominant lineages and culturally-inflicted distortions. The researchers say more work needs to be done, but are unclear if this involves archaeology or experiments involving skewing the data in the local female population."
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Humanity's Genetic Diversity on the Decline

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  • Is this news? (Score:2, Insightful)

    by mwvdlee (775178)
    Isn't this basically what that whole "survival of the fittest" thing does? End less suitable genetic traits and combine the surviving ones in an ever repeating cycle, ever closer to the "fittest" genetic blend?
    • Re:Is this news? (Score:5, Insightful)

      by krgallagher (743575) on Wednesday August 08, 2007 @10:21AM (#20156271) Homepage
      "Isn't this basically what that whole "survival of the fittest" thing does?"

      Their conclusions are not valid for all of humanity anyway. How does Western Europe equal humanity? It is already known [sciencedaily.com] that there is less genetic diversity in two Europeans from different countries than there is in two Africans from the same village. What a Eurocentric point of view.

    • Re:Is this news? (Score:5, Informative)

      by kahei (466208) on Wednesday August 08, 2007 @10:23AM (#20156299) Homepage

      No, it isn't. For one thing, diversity is itself a survival trait in a population -- a population that had actually all zeroed in on the one single 'most fit' genotype would be terribly vulnerable.

      It's misconceptions like these that make it easier for cranky American Protestants to think of 'Evolutionism' as just another faith.

      • Re:Is this news? (Score:5, Interesting)

        by mwvdlee (775178) on Wednesday August 08, 2007 @10:41AM (#20156549) Homepage
        Nobody said "fittest" is an absolute, nor even measurable. It just means "whatever has the best chance of survival in this environment". If any variable changes (such as the environment), it's likely some other trait becomes more "fit". As such; in an environment that changes rapidly, a more diverse genetic will have bigger chances, in a more stable environment, genetic markup would have the time to zero in on a particular direction. This vulnerability you describe only exists when one of the variables changes. Diversity may be (and probably is) a better trait in the long term, but in the short term it serves little purpose. There's probably millions of times in the past where diversity in human genes has grown, we happen to live in a time and environment that is stable enough for other traits to become more important than diversity and so these other traits tend to be the ones with the biggest chance of survival.
        • Re: (Score:2, Interesting)

          by edittard (805475)

          Diversity may be (and probably is) a better trait in the long term
          I'm not even sure it is a trait. Perhaps it's fair to say it's a trait of populations rather than individuals, but I don't see how in that case it can be selected for (or against) in the standard Darwinian method like skin colour or weight might be.
          • Re: (Score:2, Insightful)

            by beckerist (985855)
            I'm actually surprised by all of this. With the social programs we as a species have adopted, those individuals with crippling genetic diseases are now able to stay alive much longer and lead productive lives. With this, and as horrible as it is to say, unfortunately there is a better chance now for those individuals with disorders to reproduce. This isn't limited to disorders, but there are plenty of genetically influenced traits that thousands of years ago would have killed the carrier (ie: obesity, arthr
      • by linguizic (806996)
        Don't be so hard on the guy, after all group selectionist models like what you are espousing are currently on the fringes of sociobiological theory. Though you refrained from making a 'for the good of the species' argument, you still engaged in a form of it. Richard Dawkins has much to say about these types of arguments as does John Alcock who wrote a fantastic book called the triumph of sociobiology. I highly recommend it:

        http://www.oup.com/us/catalog/general/subject/Lif e Sciences/Ecology/AnimalBehav [oup.com]
    • by linguizic (806996)
      Actually, what this points out is that there are fewer women contributing to the gene pool since the mtDNA is copied over completely from the mother. One possible explanation for this could be the rise of modern warfare where women are military targets. Another explanation could be that this reflects the rising status of women in these societies. It's well known that there is an inverse correlation between a woman's social status and the number of children she has.
    • Re: (Score:2, Interesting)

      by OhHellWithIt (756826)

      The catch, of course, is that "fittest" depends on the environment that the organism lives in. And "less suitable genetic traits" are just the ones that happen to result in the individual's untimely death (i.e., before it reproduces). My myopia is obviously a less suitable genetic trait that could get me killed if I get into a situation where I need to see a danger at a distance. But none of my nearly-blind ancestors managed to get themselves killed before I came along, and I have managed to reproduce, an

    • by gstoddart (321705)

      Isn't this basically what that whole "survival of the fittest" thing does? End less suitable genetic traits and combine the surviving ones in an ever repeating cycle, ever closer to the "fittest" genetic blend?

      Survival of the fittest is how nature does selection.

      Societies introduce artificial changes to what defines "fittest", so this isn't necessarily a purely 'normal' evolutionary change.

      For instance, in North America, those doing the most procreation in many cases might be the least fit. They're not the

      • Re: (Score:3, Insightful)

        by hoggoth (414195)
        > Isn't this basically what that whole "survival of the fittest" thing does?

        Actually a lot of the confusion is cleared up by thinking of it as "survival of the fit enough" instead of "the fittest".

        You can roughly divide the gene pool into three categories. Those that are not fit enough to survive are quickly weeded out. Those that are very fit to survive prosper and multiply. Those that are fit enough in easy times, but not fit enough during rough times such as famine or plagues or increased competition
      • Those doing the most procreation are by definition the most fit.

        An individual that does not reproduce and does not increase the reproduction of those who shares their genes are the least fit.

        They can be brilliant, have the body of a greek god, and never get sick but if the less copies of their genes they pass on, the less fit they are (in this sense of the word).

        Currently, being religious and poorly educated appears to provide a big advantage in reproductive fitness.
  • by morari (1080535) on Wednesday August 08, 2007 @10:13AM (#20156171) Journal
    Come on down to Southern Ohio and you'll see just what I mean. The Shadow Over Portsmouth!
    • Heh. +1 for the Lovecraft reference if I had mod points.

      I think it just boils down to the increased mobility of populations allowing groups to interbreed more freely...200 years ago, you could have lots of little enclaves of genetic diversity within a few dozen miles of each other that would seldom if ever gain any genes from each other.

      These days there is no guarantee that genes won't be shared regularly across a thousand miles or more. My wife and I were born 400 miles apart. My parents were born in the s
  • by PhrostyMcByte (589271) <phrosty@gmail.com> on Wednesday August 08, 2007 @10:13AM (#20156173) Homepage

    The researchers say more work needs to be done, but are unclear if this involves archaeology or experiments involving skewing the data in the local female population.

    In the name of science, I volunteer for any experiments involving "skewing" "data" into the local female population.

    • I knew someone would.

      You people are so predictable. :)
    • Unfortunately, your contribution will do nothing to the diversity of mitochondrial DNA since it is only passed by the mother. BTW, can't that simply explain why that diversity is reducing (whomen either transmit their mitochondrial DNA, ...or not)?
  • I've never heard it called that before. Either something is missing in translation, or we should be told a bit more about what the Royal Society is like nowadays. After all, it was founded by Charles II, and he was pretty good at something that sounded a bit like skewing the local female population.
    • Yeah, I think you mean "skewering" the local female population heh...

      Seriously, genetic diversity cannot be helped by a society that favors monogamous, life-long relationships between couples. The most genetic diversity is achieved when women have children by as many different men as possible throughout their lifetimes.
      • The most genetic diversity is achieved when women have children by as many different men as possible throughout their lifetimes.


        In other words, you're suggesting that women become more like the women one sees walking about in the inner cities or appear on Maury Povich doing the paternity tests.

    • Mitochondria is carried by women (via the fact that they have the cell, where is the sperm just introduces DNA). So, by looking at just mitochondria, it is possible that the diversity was lost there, but not in the human DNA (the mitochondria is nothing more than a degraded bacteria; it even has bacterial DNA). IOW, they are saying that they may be measuring the wrong item.
      • Mitochondria are a hell of a lot more than "degraded bacteria;" try taking the mitochondria out of your cells and see how long you last. ;)

        Also, human mitichondrial DNA is just as much "human DNA" as is nuclear DNA. Sure, it was bacterial originally, but the point at which it became a vital part of our cells was very early in the evolution of eukaryotes, a looong time before there was any such thing as human being ... or a mammal ... or, for that matter, anything more complex than a jellyfish. Our mitocho
        • While the mitochondria is in a pure symbiotic relationship with the cell, it is still just a degraded bacteria (just millions of years ago). In particular, the Mitoconhondria CAN exist outside of the cell (with a little bit of help), while as you point out the cell WILL die without our little powerhouse. But the telling issue is that Mito's have the same DNA as that from bacteria (anucleas as well as the same structure as ALL prokayotes; in a centerfuge, they spin to the EXACT location of all prokayotes), w
  • Easyjet is restoring the diversity.

     
    • Re: (Score:3, Interesting)

      by DarenN (411219)
      On a serious note I've heard it argued that the ease of travel is slowing the rate of human evolution (or if you don't believe in it, human natural selection) as the chances of a even an improving mutation/trait being successful over time is much lessened in a greater pool of individuals.

      Not entirely relevant to the article, though.
      • Re:Don't worry (Score:4, Interesting)

        by hedwards (940851) on Wednesday August 08, 2007 @10:56AM (#20156739)
        That's hard to say. The ease of travel has been leading to a decrease in diversity within a species which is significantly less diverse than most other species already.

        But as was pointed out in an article I read last year, what diversity looks like may very well be in transition. I don't personally quite buy the authors suggestion, but the trend is away from distinctive racial groups and more towards groupings based upon intellect and looks.

        Which to some extent makes sense. The premium that most groups place on mating within the same group has been decreasing, at least around here, and people will always choose somebody that they find enjoyable to be around to those that are not. Frequently looks, intellect, sense of humor and health are considered selection criteria. So the idea that the groupings would be based upon that wouldn't be too outlandish.
      • On a serious note I've heard it argued that the ease of travel is slowing the rate of human evolution (or if you don't believe in it, human natural selection) as the chances of a even an improving mutation/trait being successful over time is much lessened in a greater pool of individuals.

        What about the increased chances of complementary mutations pairing up?

        Anyone who says that fusing long-segregated DNA isn't a good idea needs to take a good long look at the results [buddytv.com].

  • Some points (Score:5, Informative)

    by wandm (969392) on Wednesday August 08, 2007 @10:18AM (#20156241)
    Firstly, the article has nothing about "human genetic diversity". It's about ancient UK population having larger haplotype diversity than the many modern European populations.

    There could be a few reasons to this. Anglo-Saxons came to England around 550AD. Also Romans had settled the island. Later also Vikings came. These plus the local population already implies quite a lot of diversity.

    Since then some lineages have been more successful, that's it. Actually, this could be considered supporting evidence for D. Gregory Clark's hypothesis that upper classes have been replacing the lower ones during middle ages in England, as reported by Slashdot yesterday, see http://science.slashdot.org/article.pl?sid=07/08/0 7/2221256 [slashdot.org]
    • Remember this is only a study of mitochondrial DNA, not the DNA for the nucleus. I think it's more likely that geographic barriers have lowered, causing a reduction in diversity over time. It may also be that certain mitochondrial variations were better adapted for a thousand years ago, while they don't hold up so well in the modern world. It could be that the Black Death, for example, ended up destroying populations with certain variations or simply that the rare variations vanished.
      • Re: (Score:3, Insightful)

        by fm6 (162816)

        It may also be that certain mitochondrial variations were better adapted for a thousand years ago, while they don't hold up so well in the modern world.
        Aren't mitochondria just energy converters? How much can their conditions change, deep within the cell? Not much, I hope, since mitochondria reproduce asexually, and thus have limited ability to evolve to survive new conditions.
    • Re: (Score:3, Insightful)

      by Dr. Spork (142693)
      I thought of the same article. We need an explanation for why genetic diversity decreased so much in Europe and not in Africa (for example). And the mechanism of the wealthy families replacing the poor is a very plausible suggestion, since it has been independently shown to occur in Europe and not elsewhere. Of course the plague had something to do with it too, but that's not enough to explain the whole effect. It's important that the same population pressure applied for more than 30 generations, and that's
    • It still seems very odd to me. Humans in general are having a lot more contact across large areas, as well as more interracial relationships. Wouldn't that imply that we are, in fact, building genetic combinations within a bigger pool than, say, hundreds or thousands of years ago?
    • by KH (28388)
      This study, being on the mtDNA, I wonder how much the causes you cite may apply. Did the Romans or the Anglo-Saxons or the Vikings come to England as family? Nonetheless, even though I am not a geneticist, the article mention "selection" as a possible cause of the loss of diversity in the female population. This is sort of amusing if I think about what it might mean. Doesn't that mean that there should be a lot less... er... undesirable females in England? This is counter-intuitive from what I hear fro
  • by bomanbot (980297) on Wednesday August 08, 2007 @10:21AM (#20156263)
    They used a historic sample of only 48 ancient Britons and those were even spread out to a timeframe from about 700 years (contrary to the summary, the ancient samples lived between AD 300 and 1000 which is a relatively big timeframe).

    I would think that their analysis could still be statistically relevant, but still they say themselves that more work is needed, so I think more historic sample data would be quite useful.
  • by Reeses (5069) on Wednesday August 08, 2007 @10:22AM (#20156279)
    It's sad that scientists don't read each other's stuff. Then again, both of these articles came out at the same time, so it would have been virtually impossible.

    But the parent article refers to a phenomenon mentioned in a slashdot article about the Industrial Revolution less than a day ago. http://science.slashdot.org/article.pl?sid=07/08/0 7/2221256 [slashdot.org]

    Now the key is to see if the two groups catch on.
  • Outliers (Score:4, Funny)

    by NetDanzr (619387) on Wednesday August 08, 2007 @10:22AM (#20156281)
    If they eliminated the outliers, such as West Virginia, the average human diversity would go back to what it was in 300AD.
  • by NJVil (154697) on Wednesday August 08, 2007 @10:23AM (#20156293)
    So, as I understand it, this was written by an unattractive British science geek as a pickup line to use in bars full of attractive women.

    "Hi. We analysed the historical genetic diversity of human populations in Europe at the mtDNA control region for 48 ancient Britons who lived between ca AD 300 and 1000, and compared these with 6320 modern mtDNA genotypes from England and across Europe and the Middle East. We found that the historical sample shows greater genetic diversity than for modern England and other modern populations, indicating the loss of diversity over the last millennium. The pattern of haplotypic diversity was clearly European in the ancient sample, representing each of the modern haplogroups. There was also increased representation of one of the ancient haplotypes in modern populations. We consider these results in the context of possible selection or stochastic processes. So, you understand... you... must have... sex.... with me."

    "Are you trying to tell me that the genetic diversity of Britain is at stake if I don't hop into the sack with you?"

    "Umm... yes."

    "Yes, then. For Britannia and the queen!"
  • ...I blame West Virginia.
  • Increase (Score:3, Insightful)

    by ardor (673957) on Wednesday August 08, 2007 @10:36AM (#20156493)
    And how could the diversity *in*crease? Multiple mutations in a short timeframe?
  • Understatement (Score:3, Interesting)

    by kahei (466208) on Wednesday August 08, 2007 @10:39AM (#20156519) Homepage

    I don't really know anything about European mitochondrial DNA and I'm not entirely sure England (which was swept by various waves of invaders, not all of whom actually stayed, and then remained unchanged for a very long time) is a good example anyway. But I can say that over the last 100 years human genetic diversity (like linguistic diversity and cultural diversity) has plummeted, with truly distinct populations like the Andamanese (google them) and less-distinct but highly diverse populations like those of southern Siberia, Taiwan, and the Caucasus disappearing almost without comment.

    Unfortunately, not only is it unfeasibly difficult to prevent such loss, it is also politically well-nigh impossible even to document it, as doing so involves admitting that a given population *is* distinct which is generally unacceptable to Russia and China in one way, and to politically-correct Western academics in another way. From peppercorn hair to multi-base counting systems, the vast majority of human biology, language and tradition has been lost, and a few selected strains and languages grow uncontrollably like some kind of bizarre algal bloom. Made of people.

    This is not at all a recent phenomenon but in the last century it has massively speeded up. The catastrophic loss of ecological diversity may be just around the corner but the human equivalent has already happened and with a tiny fraction of the fanfare.

    • Re:Understatement (Score:4, Interesting)

      by Dystopian Rebel (714995) on Wednesday August 08, 2007 @10:55AM (#20156729) Journal

      The catastrophic loss of ecological diversity may be just around the corner but the human equivalent has already happened and with a tiny fraction of the fanfare.


      There have been many catastrophic losses of biodiversity on the planet and there will certainly be more before the Earth becomes barren.

      I don't agree that the loss of societal habits, misconceptions and bugbears ("human culture") can be equated. These things may be dear to people but they are mostly rubbish.
    • ...From peppercorn hair to multi-base counting systems, the vast majority of human biology, language and tradition has been lost, and a few selected strains and languages grow uncontrollably like some kind of bizarre algal bloom. Made of people....

      Well, if you have ever tried to do basic arithmetic in multi-base counting systems, you would understand why consistent bases, along with place value notation (even in non-romanic character languages like Japanese), have taken over the world. They are VASTLY ea

  • Hmm (Score:3, Insightful)

    by JMZero (449047) on Wednesday August 08, 2007 @10:40AM (#20156531) Homepage

    three out of every four individuals belonged to a different haplotype


    I remember this game from Sesame Street. They showed 4 things - 3 were different and one was the same. Same as... uh..
    • Re: (Score:3, Funny)

      I remember this game from Sesame Street. They showed 4 things - 3 were different and one was the same. Same as... uh..

      I have young kids, so I watch that show like 3 times a day. I am a Jedi freaking *master* at 'One of these things is not like the other'. You cannot defeat me.

      • by JMZero (449047)
        A while back my wife was playing a game like this online with our niece. On the screen were a flower, some corn plants, a tree, and a rabbit.

        My wife clicked the corn, because the other 3 things were pretty.
  • It is just the result of time and evolution.

    Give us another couple of years of having russians spread plutonium throughout the world and we will start having a lot MORE genetic diversity.

    I for one will welcome our two headed overlords.

  • ... we are all slowly but definitely becoming inbreeds. And it shows.
  • Anno Domini (Score:3, Informative)

    by TheNicestGuy (1035854) on Wednesday August 08, 2007 @11:07AM (#20156883)

    All right, if Slashdotters are going to continually jump all over misuse of "begs the question", then there's a pet peeve I'd like to add to that fervor. "300 AD", as it appears in the summary, is also incorrect usage. "AD" stands for anno domini, which is Latin for "in the year of the Lord". The phrase in Latin usage and traditional English usage comes properly before the number, not after. (Say it in full: "300 in the year of the Lord" sounds like an explanation of when something's tricentennial occurred. "In the year of the Lord 300" makes more sense as an absolute time reference.)

    The convention of putting "AD" after the number is nothing but sloppy analogizing to "BC", which (being the English phrase "before Christ") does make more sense that way.

    Note that the Royal Society writers did get it right. It's the Slashdot summary that's wrong.

    • YEAH! I'm not the only one.

      The really weird thing about this is that at the turn of the century people were getting it right! WTF happened? Is 9/11 to blame for that too? Did people get stoopid after 9/11?

      • by Kjella (173770)
        Civilization happened... I know it means anno domini and a rough translation, but I always assumed you could use it like 300 AD = "300th year of our Lord". I just verified from some screenshots that Civ4 still uses the post-notation, and I know I learned it from the original Civilization game.
    • by FiloEleven (602040) on Wednesday August 08, 2007 @11:55AM (#20157605)
      IN A.D. 2101, WAR WAS BEGINNING

      (lameness filter encountered. I suppose the mods will decide if it's accurate or not. Personally, I think this parenthetical bit ruins the joke. Lame.)
    • If you're going to be pedantic, do it right. "Anno Domini" can be translated varying ways. "Anno" is the dative case, which can several strange usages depending on the context in the sentence--just read Virgil to get a sense of just how versatile it could be. The common translation "In the year of our Lord" is hardly precise. Romans who would have used similar phrase (this exact phrase did not come into wide use until the ninth century) would not have understood it to mean the same as the prepositional phra
  • TFA brings up an important issue, but an obvious one. Over time, similar ethnic groups mixed in a nation (the UK) become closer to one. If a species appears on one continent, the farther it goes from that continent, the more it loses genetic diversity as it gets specialized for the new, foreign environment. All the other whinging is FUD by those who fear science just as much as the Christian fundamentalists do.

    Go get yourself DNA tested already, so you know what diseases you're going to inherit and whether
  • Royals.... (Score:2, Interesting)

    Has anyone ever done a study on what is probably the most inbred population on the planet - the European royals?
  • by 140Mandak262Jamuna (970587) on Wednesday August 08, 2007 @11:50AM (#20157535) Journal
    You know, if preserving genetic diversity and variation is really important, there is nothing like endogamous marriages. Marriages between parallel cousins. Marriage between the offspring of two brothers (or two sisters) would be called parallel cousin endogamous marriages. The cross cousin marriages (between offspring of a brother and his sister) is sometimes called endo but some dispute it and say it is exo. But is the genetic diversity brought about by such marriages worth it?

  • Huh (Score:3, Funny)

    by Quiet_Desperation (858215) on Wednesday August 08, 2007 @12:02PM (#20157711)

    skewing the data in the local female population

    So that's what they call it now.

  • ... according to popular belief, we all came from Adam and Eve....

    This also makes me think of the tower of babel for some reason...

    Maybe what was needed is the diversity of trial and error to then figure out we had it right to begin with.

    or some such line of thinking.

    But if there really is a lack of diversity problem, we certainly know enough about genetics even now to inject all sorts of genetic deviations.
  • by A nonymous Coward (7548) * on Wednesday August 08, 2007 @01:09PM (#20158803)
    I don't understand how the comparison can even be close to valid. The ancient group spans 700 years, the modern group is one snapshot. I dare say that any 700 year group would show more diversity than any single snapshot.

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