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Humanity's Genetic Diversity on the Decline
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."
Come on down to Southern Ohio and you'll see just what I mean. The Shadow Over Portsmouth!
"He who can destroy a thing, controls a thing." --Paul Atreides, Dune
In the name of science, I volunteer for any experiments involving "skewing" "data" into the local female population.
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.
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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/
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.
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.
Their conclusions are not valid for all of humanity anyway. How does Western Europe equal humanity? It is already known 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.
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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.
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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/
Now the key is to see if the two groups catch on.
Reeses
If they eliminated the outliers, such as West Virginia, the average human diversity would go back to what it was in 300AD.
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!"
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.
Whence? Hence. Whither? Thither.
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.
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...I blame West Virginia.
"Ask not what your country can do for you." --John F. Kennedy
I know! What a bunch of malarky. Everyone knows that North America equals humanity, not Western Europe. Duh!
And how could the diversity *in*crease? Multiple mutations in a short timeframe?
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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.
Whence? Hence. Whither? Thither.
I remember this game from Sesame Street. They showed 4 things - 3 were different and one was the same. Same as... uh..
Let's not stir that bag of worms...
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.
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While you are indeed a prime example of what you describe, I don't think the issue is as widespread as you suggest.
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Most importantly, it is the correct combination of genes that makes a successful organism as well as individual genes. 'Mixing' of groups of people is hugely advantageous for this reason.
Secondly, genes do not become lost when they combine with genes from another person to make a child. There is just a new combination of genes which can contribute to the whole genetic diversity of mankind. For example, we could take the idea that races should not interbreed a little further and say that people should not breed outside of their immediate family. The problem with this would be that genetic diversity could hardly ever increase, and by attrition mankind would be doomed. By separating races one creates several smaller separate gene-pools each of which is smaller than the original whole and hence more vulnerable.
Thirdly, by separating the societies it would become genetically/evolutionarily advantageous for one race to think of or treat the others as subhumans. By this argument I claim that you have implicitly invoked Godwin's law.
Also, I wish you luck procreating with your sister...
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.
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, and so this bad trait has been propagated to another generation. There seem to be certain diseases that are like that as well. Some inherited traits just happen to help a genetic line survive, and some of them just happen to not to have caused it to be extinguished.
I remember an article a few years ago that essentially said that the current generation of people is composed of a very small sample of the people who lived in the Middle Ages (to pick an epoch). Most of the family lines of that earlier epoch have been extinguished, for whatever reason. So in essence, we are whittling down to some few genetic lines that will have been lucky enough to make it that far. Whatever it is, it won't be perfect.
I think this is news because it is confirmation of an old idea that is still hotly debated.
"Who controls the past controls the future. Who controls the present controls the past." -- George Orwell
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.
Not at all. Me thinks you do not understand the concept of scientific reasoning as well as one might hope. It is a theory 'not based on the existence of a creator', which is a far cry from 'a theory based on the NON-existence of a creator'. Not assuming the existence of a 'creator' (whatever one may choose to mean with that) one does ones best to understand and explain observed phenomenon in a rational manner. While one cannot yet prove that the flying spaghetti monster does or does not exist through repeatable experimentation (and people should feel free to contribute their research in this area to the scientific community as a whole), one can make a very good description of the functioning of the world around us without having to tackle the issue of the influence of his omnipotent noodly appendages.
You tell 'em, Uncle Daddy!
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Why should anyone care about populations outside of his/her own? It's not natural to do so.
You can't handle the truth.
Has anyone ever done a study on what is probably the most inbred population on the planet - the European royals?
I assume you are referring to the US public schooling system. In which case you are quite right and it worries me to see that in the US children are increasingly taught that scientific reasoning must depend on such assumptions. This turns the whole debate away from what it should be. This is why, when I have visited the US I have never dared wear my "Just Say No To Evolution" T-shirt for fear that people might think it anything other than a cynical joke about this debate. Over here in Britain we are only just beginning to feel the effects of the Christian Nonsense Lobby in our state schools and it has yet to provoke the sort of outrage that leads people to publicly make idiotic arguments against it for lack of understanding of the perfectly good ones.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I went to a US public school where our principal told the senior class that we were damn well going to go to a prayer session before graduation or we wouldn't get our diplomas, despite a Supreme Court ruling the same year that held that even holding such a ceremony was definitely illegal. Yeah, our entire school system is run by a bunch of atheist communists who hate religion. Right.
This oppression is also why it's absolutely impossible to get elected President unless you're an avowed Atheist.
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When you have a theory that explains the natural world as perfectly as evolution does, invoking a creator just because not having one makes you uncomfortable is a terrible unparsimonious thing to do. If there's a bias here, it's that science tends to favor the simplest explanation that can explain the observed facts.
(And that's without even going into the massive amount of questions invoking a creator invokes in the first place.)
Keep in mind, though, that evolution is not a theory about the origin of the universe, just about life. If you really want a gap for your god to hide in, have him hide "before the Big Bang".
skewing the data in the local female population
So that's what they call it now.
When you send huge portions of your peak reproductive populaiton through the meat grinder in the span of about two generations, you can probably expect a decrease in genetic diversity. The good news about the next World War is that it will be nuclear and with all the radiation will come mutations which should help out with the genetic diversity issue.
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While seriously defective individuals, at least from a genetic perspective, are able to lead long lives in many cases because of technology and wealth, their reproductive success probably still isn't up to par. And that's really what fitness measures, not survivability, but survivability passed to subsequent generations. You could be the baddest lizard on the face of the planet, but if you eat all of your prospective mates, your fitness is effectively 0. And a lot of those "defective" genes exist for a reason. The gene for sickle cell anemia is the textbook example. Homozygous expressed, and you're dead from blood clots. Homozygous unexpressed, and you're dead from malaria. Heterozygous, and you have a competitive advantage compared to everyone else. Genetic fitness for an individual is more or less a dice roll.
You might say, "ID is stupid when there's this perfectly good scientific explanation". Well, if you regard invoking a creator as "stupid", then you've shown that you're biased against that idea, just as I am biased against the idea that the universe "just happened" without a purposeful, creative agent behind it.
ID is stupid, not because it invokes a Creator, but because it pretends to be a scientific theory while invoking a Creator whose existence cannot be proven or disproven. ID is non-falsifiable, ergo not science, and is merely Christian theology dressed up with scientific terminology in order to get around the Separation Clause of the 1st Amendment. So it's not just stupid, it's also despicable.
And yes, I realize there are a lot of people who believe both -- the "God created the mechanism of evolution" view. That's fine, but for me I think that view assumes a solider scientific foundation for evolution than actually exists.
As someone who does believe both, you're wrong. The only thing I'm am completely sure of and believe absolutely, as a matter of faith, is that God created the Universe. What I'm not so sure about is how He did this, and how exactly this universe He created works.
However there is a very solid scientific foundation for evolution -- I think your view assumes that it isn't, but there are few theories as well tested as evolution, in fact you probably hear about one of the greatest predictive successes of evolution on a daily basis, which is DNA. Is it possible that evolutionary theory is wrong, and not just inaccurate and in need of tweaking but completely, utterly wrong? Sure. I welcome any proof anyone may have that this is the case, though just like proving Relativity is completely wrong that doesn't seem very likely. In any case, the theory is well tested and until such time as it fails testing I'm going to go with it.
Note that this is completely different than "assuming" or even more so different than having faith in evolution.
ID does nothing but confuse the issue of faith and scientific reasoning by adding "and God did it" to a scientific theory. Only worse they try to pretend that it isn't necessarily "God" but some "intelligence" because actually saying God would defeat the purpose of getting Creationism into schools. ID is stupid.
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> 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 will probably pass their genes through to future generations, but not in as large numbers as the very fit.
In modern times the middle group is extremely large. Most diseases and deformaties have moved from the 'not fit' group to the 'mostly fit' group. As long as our technology keeps natural disasters and challenges at bay, there is NO reproductive advantage to being 'the most fit'. Therefore we will never evolve into "supermen" or any kind of "advanced" version of the Human race.
This doesn't have to be thought of as 'weakening' the race. Allowing 'mostly fit' individuals to propogate allows other perhaps more important traits to propogate. For example, people like Stephen Hawkin who are physically near the edge of "fit enough" but have high intelligence that may save our race from some types of disasters. For another example 'mostly fit' individuals that may have resistence to some future deadly disease.
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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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How is it any less complex than a "part" of the universe suddenly appearing and spontaneously creating the rest? Neither has a cause. Linguistic complexity doesn't really determine causal complexity. Case in point: note that the "God theory" can be summarized as "a part of the universe, called God, appeared and spontaneously created the rest." The Big Bang can be summarized as "a part of the universe, called a singularity, appeared and spontaneously created the rest."
After all, I am strangely colored.
The Canadians took them...... damn canadians
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I would like to see any examples of predictions based on evolution. I've actually grown more skeptical of it the more I study about it. To be clear: I'm not saying I don't believe in DNA or inherited traits (that would seem crazy - even to me).
Well then like I said you're already aware of one of the greatest triumphs of the theory. Long before microbiology was anywhere near advanced enough to find it, evolutionary theory predicted that there would be found a biological mechanism for passing traits between parents and offspring through reproductive cells. Many years later we discovered DNA, the very mechanism of heredity that evolution predicted. It even works largely how the theory predicted, with a mixing of portions of the parent's traits, and with random changes possible as well.
I even believe in natural selection changing traits of a population over time. What I am increasingly skeptical of is those minor changes ever adding up to an entirely new species, or leading to things as diverse as a dog and a lobster, or the first functioning eyeball. I just doubt that a species has that great a "range" of potential change.
Ah, micro- vs macro- evolution. Okay, so just to be clear, you believe that natural selection can change the traits of a population over time, that the random mixing of parent's genes and random mutations can create new traits? Do you believe it is impossible for any series of changes, no matter how many millions of years it took for them to occur, could possibly change Species A enough that you would no longer recognize it as being Species A? And do you believe it is impossible for any such series of changes to cause two sub-groups of Species A separated by geography to no longer be able to interbreed?
Because those two things put together is how micro-evolution becomes macro-evolution. Once a species splits into two subgroups that cannot interbreed then each is on their own evolutionary path. Since each will experience different changes over time, they will eventually diverge enough that they are clearly different species, and eventually to the point where one might presume that they could never have been the same species.
I doubt it's additional study of evolutionary research that has caused you to doubt that species have that much "range". Since in labs they've done things as diverse as getting bacteria to eat oil or plastics, to growing extra wings on flies. It's not a matter of "range" -- the "range" is anything DNA can express and we have yet to come close to putting limits on that.
Ring species are an interesting aspect of evolutionary research as well. These are species that started on one side of a geographic obstacle like a mountain range, and then spread in both directions around it until eventually the two branches meet on the other side. Yet because over the time it took for the populations to spread, they underwent enough genetic changes that the end points of the two branches are incapable of breeding with each other.
The first functioning eyeball was probably a single photo-sensitive nerve that could detect light and dark. This would be a major survival trait, and not out of the realm of imagination. More nerves closer to the surface, a clear membrane forming over them, the membrane filling with liquid to create a lens to focus more light, new kinds of photo-sensitive neurons to detect new wavelengths of light, none of these sound like particularly unlikely leaps though I'll admit I'm just speculating. I just don't see how that adds up to "impossible".
Besides, where did Archaeopteryx even come from then if it's impossible for any species to change into something so radically different? Where did mammals come from? "God" being both a theologically accurate but scientifically inadequate answer.
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Grr. Now it looks like i dropped a not and my correction is incorrect.
Okay...
IF they don't breed and the others outbreed them and then the others kill them, their decision to not breed will have been stupid (even tho everyone ultimately dies when the out-breeders ultimately starve due to overbreeding).
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I believe that you can add 1 and 1 together and get 2. And that you can add 1 to that result to get three, and so on. What I'm skeptical of is that those minor changes could ever add up to a million, or to integers as diverse as 32 and 13429, or a prime number. I just doubt that math has that great a range of potential change.
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Well, to start with, you're mixing up the genotype and the phenotype. But I'd rather not get into any more detail since my explanations are nowhere near as accurate, clear, or concise as the "layman's guides" available...I highly recommend Ernst Mayr's or Stephen Jay Gould's work and will leave it at that.
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