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."

Comments

Is this news?

[mwvdlee]

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?

[krgallagher]

"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 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?

[TheEmptySet]

"It's just that it's a theory based on the NON-existence of a creator."

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.

Re:Is this news?

[beckerist]

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, arthritis, diabetes) if they were being chased by some wild animal, effectively progressing towards weeding it out of the gene pool.

Though, in the same light, it's geographical distinction that most commonly affects genetic distribution and overall genetic manipulation (over time.) Given the ease of relocation and more liberal ethical philosophies in deciding our mates (compare to 50+ years or just 2 generations ago) I understand the dramatic decrease...

Re:Is this news?

[Cairnarvon]

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".

Re:Is this news?

[Xonstantine]

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.

Re:Is this news?

[Chris Burke]

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.

Re:Is this news?

[hoggoth]

> 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.

Re:Is this news?

[poopdeville]

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."

Re:Is this news?

[Chris Burke]

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.

Re:Is this news?

[Zenaku]

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.

Increase

[ardor]

And how could the diversity *in*crease? Multiple mutations in a short timeframe?

Hmm

[JMZero]

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..

Parent's borderline racist argument is also silly

[TheEmptySet]

The parent makes several glaring mistakes in his reasoning.

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...

Re:Some points

[Dr. Spork]

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 long enough for some pretty impressive consequences to emerge.

Disparate time elements

[A nonymous Coward]

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.

Re:Unlikely

[fm6]

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:Two World Wars will do that for you.

[SpecTheIntro]

This is one of the fundamental hopes of evangelical religion

Fixed that for you.

I can't think of a single religion that doesn't want to see its beliefs embraced by the entire world. That's the point of religion--you believe you've found the truth and as a result you structure your life around that truth. If you call yourself a follower of a religion, and then follow it up with "but I think other religions are equally true," then why believe in your particular truth? What motivation do you have? There must be something special about what you believe in order for you to believe it, else you're just being irrational. (Which, contrary to the typical slashdot sentiment, is not the root of all religion.)

However, I recognize that what you were really trying to do was call Muslims crazy. I am a Muslim, and I will mention that I have absolutely no desire to see the particular brand of Islam al-Qaeda and co. are supporting spread through the world. It's amusing that the very reason I chose to be Muslim is the antithesis of what radical Islam uses as its rallying cry. But getting people to think rationally about what they believe is more difficult than engendering blind faith.

On a side note, does anyone know how to code strikethrough on slashdot? I tried s, strike, and del, and none of them worked.

Re:Two World Wars will do that for you.

[Anonymous Coward]

Ok, I'm the AC that wrote the GP. I have to say... I agree with you in part. Depending on the theological views of various Christian groups, they might also have the same hope resulting in the same conclusions on how to bring the result about. I assume you were suggesting Christianity, since it's really the only evangelical religion. Evangelical meaning to "preach the gospel(good news)." Which is a means that emphasizes the personal volition as necessary for true salvation and compulsory conversion by military or social means insufficient for salvation and therefor an undesirable means.

I would point out that there were a couple of distinctions I made concerning the author. One was the issue of them being a Fundamentalist Islamic. Perhaps I should have said supporter/believer in militant Islam. My mistake, I should have been more careful since I know the sensitivity of the subject. Second, I said, "This is one of the fundamental hopes of Islam, that it would cover the Earth

• by any means possible eliminating all who oppose."

I know there have been quite a few Christians in the past that have used compulsory means to convert individuals and populations, but it's a difficult position to argue for if one believes the Christians scriptures are from God and infallible. For example:

"Bless those who persecute you; bless and do not curse. Rejoice with those who rejoice; mourn with those who mourn. Live in harmony with one another. Do not be proud, but be willing to associate with people of low position. Do not be conceited.

Do not repay anyone evil for evil. Be careful to do what is right in the eyes of everybody. If it is possible, as far as it depends on you, live at peace with everyone. Do not take revenge, my friends, but leave room for God's wrath, for it is written: "It is mine to avenge; I will repay," says the Lord. On the contrary:
"If your enemy is hungry, feed him; if he is thirsty, give him something to drink. In doing this, you will heap burning coals on his head." Do not be overcome by evil, but overcome evil with good."

I wasn't exactly calling Muslims crazy, but rather, I believe many Muslims are mean people who highly regard revenge as a responsibility and a virtue. I'll be kind to any Muslim I meet, but at the same time I realize there are a great deal of Muslims(especially Arab Muslims) who want all Christians dead or converted. So there is some in-equity. Americans, Europeans and Christians generally do not wish for Arabs or Africans or Muslims to be dead, but Muslims wish for their death. Why is this? That is the sad reality I wanted to help uncover. I simply will not pretend there is peace where there is no peace.