Natural selection is not the only process that drives evolution

Jan 27, 2009

Why have some of our genes evolved rapidly? It is widely believed that Darwinian natural selection is responsible, but research led by a group at Uppsala University, suggests that a separate neutral (nonadaptive) process has made a significant contribution to human evolution. Their results have been published today in the journal PLoS Biology.

The researchers identified fast evolving human genes by comparing our genome with those of other primates. However, surprisingly, the patterns of molecular evolution in many of the genes they found did not contain signals of natural selection. Instead, their evidence suggests that a separate process known as BGC (biased gene conversion) has speeded up the rate of evolution in certain genes. This process increases the rate at which certain mutations spread through a population, regardless of whether they are beneficial or harmful.

"The research not only increases our understanding of human evolution, but also suggests that many techniques used by evolutionary biologists to detect selection may be flawed" says Matthew Webster.

BGC is thought to be strongest in regions of high recombination, and can cause harmful mutations can spread through populations. The results lead to the provocative hypothesis that, rather than being the result of Darwinian selection for new adaptations, many of the genetic changes leading to human-specific characters may be the result of the fixation of harmful mutations. This contrasts the traditional Darwinistic view that they are the result of natural selection in favour of adaptive mutations.

Reference: biology.plosjournals.org/perls… journal.pbio.1000026

Source: Uppsala University

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gmurphy
3 / 5 (6) Jan 27, 2009
incorrect, this is a form of mutation, not selection.
smiffy
3.8 / 5 (4) Jan 27, 2009
They're not claiming that it's a form of selection.
They are saying that it's a new driver of genetic change, which in turn drives evolution in some cases.
Szkeptik
2.6 / 5 (5) Jan 27, 2009
If this is true it's a pretty shocking discovery in the field of evolutionary biology.

A disadvantageous mutation spreading in the population? As long as the animal needs to mate to pass it's genes on, bad characteristics will always be filtered out. I've never heard of this BGC but it has to be more than this article shows it to be.

As we know extraordinary claims require extraordinary evidence, and I don't see any of it here.
JayVenter
2.8 / 5 (4) Jan 27, 2009
I don't know much about evolution, so try not to flame me, but if disadvantageous properties get filtered out by natural selection, wouldn't that mean that all species on earth would inevitably be perfect or flawless ?
Szkeptik
4 / 5 (5) Jan 27, 2009
JayVenter: No. Natural selection only takes place when there is an environmental factor that acts negatively on a species. If a species reaches an optimal and uniform survival and reproduction rate within the given environment that species evolution can slow down to almost a halt. Then as the environment changes and the species is no longer an optimal survivor - and that always happens sooner or later - selection pressure rises again as those least suited for the new conditions die of with a higher probability than those that are physically better off. This "rapid" adaptation than slows down again as the species nears the optimum again.

Of course there's a physical barrier too, that's why we don't see gazelles and lions racing on supersonic speeds.
TrustTheONE
1.4 / 5 (10) Jan 27, 2009
You need faith to believe in evolution, besides its agains the second law of physics.
BUT, Mutation really occurs and its tottaly different!

Believe you came from monkeys just because you dont understand why you have an appendix is really smart...
kgbdrop
2 / 5 (2) Jan 27, 2009
Szkeptik: There are also arms races between predator and prey which mean the environment never stays the same.
GIR
4 / 5 (7) Jan 27, 2009
You need faith to believe in evolution

No you don't. Evolution is observed. Faith is belief without evidence and will not change with new evidence. Belief based on evidence is malleable and will change if new evidence proves an old belief to be wrong.

besides its agains the second law of physics.

No it isn't. That is an outdated argument that most informed ID proponents have abandoned. It's not even worth debating anymore. If you are going to argue against evolution on a science site you might want to keep your arguments up to date.

BUT, Mutation really occurs and its tottaly different!

Random beneficial mutations contribute to the evolutionary process.

Believe you came from monkeys just because you dont understand why you have an appendix is really smart...

I don't remember anyone saying that having an appendix is proof we came from monkeys. We didn't "come" from monkeys. We share a common ancestor. That ancestor was a primate. Not all primates are monkeys.

It is obvious that you don't even understand the basic principles involved in the pro-evolution side of the argument. I don't mind debating well informed ID proponents but you are weakening your own position and making IDers look bad with you faulty logic, outdated arguments, and that last insult you just had to throw.

I'll give you the benefit of the doubt and assume you are frustrated or having a bad day. Hit reset and try again the next time an article on evolution comes out. :P
TrustTheONE
1.5 / 5 (8) Jan 27, 2009
ok show me the intermediate specie!

ohh even darwin told it was a problem for the Theory :(
GIR
4.3 / 5 (6) Jan 27, 2009
Archaeopteryx is one of the most well known intermediate species that shows the transition from dinosaurs to birds.

If you are referring to humans this is from wikipedia.

"This list is in chronological order by genus.

Sahelanthropus
Sahelanthropus tchadensis
Orrorin
Orrorin tugenensis
Ardipithecus
Ardipithecus kadabba
Ardipithecus ramidus
Australopithecus
Australopithecus anamensis
Australopithecus afarensis
Australopithecus bahrelghazali
Australopithecus africanus
Australopithecus garhi
Paranthropus
Paranthropus aethiopicus
Paranthropus boisei
Paranthropus robustus
Kenyanthropus
Kenyanthropus platyops
Homo
Homo habilis
Homo rudolfensis
Homo ergaster
Homo georgicus
Homo erectus
Homo cepranensis
Homo antecessor
Homo heidelbergensis
Homo rhodesiensis
Homo neanderthalensis
Homo sapiens idaltu
Homo sapiens (Cro-magnon)
Homo sapiens sapiens
Homo floresiensis"

Just because the fossle record is incomplete doesn't invalidate the record. 1, 2, 3, 4, , 6 does not invalidate the existance of 5; it predicts it.

http://en.wikiped...ergensis
(You may have to paste the links. I'm having trouble with them. Sorry.)


There's the first one to bury their dead. They used stone tools. Their hearing was close to modern humans and very different than chimps. They butchered their prey as evidenced by cut marks on the bones.

Check out the pic
http://en.wikiped...446).jpg

If you actually look at the time frames involved the progression is clear.


Roj
1 / 5 (1) Jan 28, 2009
Like the other creationist dullards, ..you would say there are now two gaps.


Those familiar with church know it's more like two nipples wanting their children, if only they believed in God. Most men are easily persuaded.
Velanarris
5 / 5 (2) Jan 28, 2009
You need faith to believe in evolution, besides its agains the second law of physics.
Wrong, evolution makes organisms a better user of energy which is directly in line with entropy.

BUT, Mutation really occurs and its tottaly different!
And what do you think causes that? If it was made by "God" then DNA wouldn't mutate, after all, he made us "perfect" in his image. What are the religous rationalizations for DNA itself? DNA is part of free will? If that's the case then the religous arguments against DNA manipulation are based on falsehoods.

Believe you came from monkeys just because you dont understand why you have an appendix is really smart...
Then explain why your perfect Gods gave us one. Did he make a mistake? Or did free will develop one for us?


Sorry, I typically follow the middle of the road on these discussions becvause most people of religion I've talked to are rather rational about the subject and don't invent ridiculous arguments.
johanfprins
2 / 5 (4) Jan 28, 2009
Evolution is real: I have experienced evolution during my own lifetime. When I was young I was a homo erectus. Now in my sixties I have become a homo sapiens: I can now only think about it! I thus have experimental confirmation!
TrustTheONE
1 / 5 (2) Jan 28, 2009
Right now the discovered black matter running away from a black hole, what means that plus E can be achieved, so now all evolutionist need to run to their desk to build up new explantions and mold theie "science" to the new finding. But to ID it still perfect.
TrustTheONE
1 / 5 (3) Jan 28, 2009
For you is easier to believe in gas cloud explosion, (where that gas came from ?????) than to believe in an intelligent
design.
If the second is real, than there is a GOD that will judge you, there must be a law and as you dont want do follow any laws and want to live the life your own way, so is a relief to yourself to believe in the gas cloud explosion.

At least you should recognize that.

Wrong, evolution makes organisms a better user of energy which is directly in line with entropy.
And what do you think causes that? If it was made by "God" then DNA wouldn't mutate, after all, he made us "perfect" in his image. What are the religous rationalizations for DNA itself? DNA is part of free will? If that's the case then the religous arguments against DNA manipulation are based on falsehoods.

Then explain why your perfect Gods gave us one. Did he make a mistake? Or did free will develop one for us?

Sorry, I typically follow the middle of the road on these discussions becvause most people of religion I've talked to are rather rational about the subject and don't invent ridiculous arguments.

Velanarris
5 / 5 (3) Jan 28, 2009
For you is easier to believe in gas cloud explosion, (where that gas came from ?????) than to believe in an intelligent
design.
Ok, so it's completely unrelated topic time, I can play this game too.

Is God willing to prevent evil but not able? Then is he impotent?

Is God able but not willing? Then is He malevolent?

Is God both able and willing? Whence then is evil?

Is God neither able nor willing? Then why worship him?
- Epicurus

If the second is real, than there is a GOD that will judge you, there must be a law and as you dont want do follow any laws and want to live the life your own way, so is a relief to yourself to believe in the gas cloud explosion.

Belief in a being that sits in paradise and casts judgement upon my loved ones, my countrymen, my enemy, and myself whilst making us to suffer for the impulses and ideaology that he instilled upon us, who will if offended then cast us from Earth into a pit of fire and wrath and hatred to suffer unspeakable tortures for the remainer of eternity must give you great solace. He must really, really love you unconditionally.

At least you should recognize that.
I think I've come to the realization that the only being that is deserving of my unfettered faith is myself. It's unfortunate that you require fantasy to get through your day. Perhaps, you should recognize that your faith is your crutch and your weakness is made plain by your commentary and misgivings.

To those among the faithful that enjoy religion in a non-zealous non-fanatical way, please ignore my commentary as you are undeserving of the slight.
E_L_Earnhardt
1 / 5 (1) Jan 28, 2009
The greatest faith I have encountered made the statement: "It Just Happened"
GIR
3 / 5 (2) Jan 28, 2009
Right now the discovered black matter running away from a black hole, what means that plus E can be achieved, so now all evolutionist need to run to their desk to build up new explantions and mold theie "science" to the new finding. But to ID it still perfect.


Why did you change the subject? That has nothing at all to do with evolution. Dark matter and black holes have nothing to do with how life developed into what it is now here on earth.

For you is easier to believe in gas cloud explosion, (where that gas came from ?????) than to believe in an intelligent
design.


Now you are moving into the origin of the universe. Once again why are you changing the subject? We were debating evolution remember?

All you have done is throw out unsupported arguments. You make no attempt to back them up with any evidence and when you are challenged you don't defend them.Instead you make new unsupported arguments or change the subject completely.

(where that gas came from ?????)

Where did God come from?

You can't support a single thing you have said on this thread can you? You just try (and fail) to poke holes in our arguments but you can't defend your own. You don't even try. That is the weakest possible form of discussion/debate. Sad.

Velanarris
not rated yet Jan 28, 2009
I'm guessing he's from Westboro.
superhuman
not rated yet Jan 31, 2009
You need faith to believe in evolution, besides its agains the second law of physics.
Wrong, evolution makes organisms a better user of energy which is directly in line with entropy.


I guess second law of physics is to mean second law of thermodynamics, which states that in an isolated system entropy can never decrease (bar some microscopic fluctuations).

Evolution is certainly not against this law since the entropy of the complete system always increases. If there is a local decrease in entropy in one place, for example DNA strand is being synthesized, it is always balanced by an even greater increase in entropy somewhere else, in the case of DNA it's hydrolysis of pyrophosphate.

However the fact that evolution makes organisms more energy efficient does not matter from the POV of second law and it is not always the case.

For example a cell might evolve to produce twice as many of a certain protein which makes it overall less energy efficient, however if this change protects it from some threat like a viral infection which wipes out other cells, this change will be selected for and will be kept, at least as long as the threat persists.

As for the article it is well known that "Natural selection is not the only process that drives evolution" natural selection has to select from something, if there were no mutations natural selection would not lead to any evolution whatsoever.

The article only states that certain genes in humans mutate faster then in related species, there may be very good reasons for this accelerated mutation rates which we simply don't know.

The results lead to the provocative hypothesis that, rather than being the result of Darwinian selection for new adaptations, many of the genetic changes leading to human-specific characters may be the result of the fixation of harmful mutations.


Not really it only shows that more mutations are being produced but it does not show that harmful mutations are being *fixed* in the population.

Standard explanation makes much more sense - additional mutations provide the pool of alleles from which natural selection picks those most beneficial and fixes them in the population (of course the process is probabilistic so some negative changes can also get fixed sometimes).
Velanarris
not rated yet Jan 31, 2009
However the fact that evolution makes organisms more energy efficient does not matter from the POV of second law and it is not always the case.
You're correct, I misstated.

My intent was that evolution makes the organism a better mechanism for energy dispursement, thus adding to the chaos of the system.

Afterall, sometimes order will arise giving way to greater levels of chaos
smiffy
not rated yet Feb 01, 2009
I don't agree with the assertion that life increases entropy, as two researchers from the University of Helsinki have recently proposed -
http://www.physor...302.html
While it's true that life doesn't breach the second Law of Thermodynamics (nothing does) it does in some small way resist it, in the sense of slowing down the rate of increase in energy dispersion.
Consider photosynthesis. Here energy from the sun is 'trapped' in sugars in living plants and later on in stores of carbon that are held for hundreds of millions of years (coal, oil etc). What would have happened to that energy if life had not existed on Earth? If there were no biosphere the sun's radiation would have heated the planet up by day, only for the Earth to later re-radiate the energy out to the the four corners of the cosmos.
I don't know of any phenomenon other than life that has this braking effect.
(With the possible exception of Gravity - and here I'm on much shakier ground since it's not two geologists from Finland I'm disagreeing with, but with Roger Penrose and Stephen Hawking)
Velanarris
not rated yet Feb 01, 2009
Smiffy -

Gravity is necessary for nuclear fusion. Making it in line with entropy at least in that regard.

As for life putting the brakes on entropy you have to assume that there are no other chemical changes that occur to store the sunlight. Nutrients are pulled from the ground, the energy bonds are broken in the sugar at night releasing co2 and other trace gasses. If you extend the timescales you are examining life has very little "negative entropy" and on larger scales directly assist entropy.

smiffy
not rated yet Feb 01, 2009
Well I suppose I'm going to concede the gravity section. Although gravity apparently increases the amount of orderliness and therefore a reduction in the amount of randomness, that doesn't mean a reverse in entropy. Forget I mentioned gravity.

As for life resisting the increase in entropy at larger timescales you are of course right. It's a bit like building a wall of sand against an incoming tide. You can keep one small area of beach drier than than neighbouring areas only for so long.
In the end life will have made no difference. But I maintain that it does resist while it can, and does have a braking or slowing effect. I'm not claiming 'negative entropy', by which I take you to mean a decrease in entropy. Entropy always increases. But the rate at which it increases can vary, and it still seems to me that life reduces this rate compared to inanimate matter.