Sex with Neanderthals boosted human immunity

[kmr]

On a second note, if we were capable of interbreeding with neanderthal, why are we classified as different species, instead of sub-species? Is this just a special case?

[BGoodForGoodSake]

When it comes to general adaptation and natural selection, our new societies have kinda eliminated such possibilities... having lighter or darker skin no longer increases your chance for survival in any given place. In the days before modern transportation, food surpluses and medical care, having darker skin in an environment with lots of sun meant that over time (lots of time) your descendants got cancer less, had fewer birth defects and generally were able to function with greater ease in a hot environment. In turn, the descendants of theirs who had darker skin also received such results, and so on. It is not necessarily a matter of mutation, although it often is. The thing is that if you just take a white population and dump it in Africa for twenty thousand years, they won't necessarily become black anymore because we have developed ways to compensate for the extra sun (I.E, sun block, shelter, and shaded, fast transportation).

At least, that is the theory.

Quite a simplistic view of evolution you have there.
We may not have the same selective pressures, but I have a sneaking suspicion that selective pressures still exist.
And on the other side of the equation the variation of traits and appearance of new traits is probably accellerating at a pace never before seen for the human race.

[Byblos]

When it comes to general adaptation and natural selection, our new societies have kinda eliminated such possibilities... having lighter or darker skin no longer increases your chance for survival in any given place. In the days before modern transportation, food surpluses and medical care, having darker skin in an environment with lots of sun meant that over time (lots of time) your descendants got cancer less, had fewer birth defects and generally were able to function with greater ease in a hot environment. In turn, the descendants of theirs who had darker skin also received such results, and so on. It is not necessarily a matter of mutation, although it often is. The thing is that if you just take a white population and dump it in Africa for twenty thousand years, they won't necessarily become black anymore because we have developed ways to compensate for the extra sun (I.E, sun block, shelter, and shaded, fast transportation).

At least, that is the theory.

Quite a simplistic view of evolution you have there.
We may not have the same selective pressures, but I have a sneaking suspicion that selective pressures still exist.
And on the other side of the equation the variation of traits and appearance of new traits is probably accellerating at a pace never before seen for the human race.

Such as?

And do you see those new traits mutating beneficially (and how)?

[BGoodForGoodSake]

Quite a simplistic view of evolution you have there.
We may not have the same selective pressures, but I have a sneaking suspicion that selective pressures still exist.
And on the other side of the equation the variation of traits and appearance of new traits is probably accellerating at a pace never before seen for the human race.

Such as?

And do you see those new traits mutating beneficially (and how)?

I am sure I said probably, I do not have any examples. The thinking goes as follows. Since we are all born with mutations, and mutations can lead to new traits, and the population is very large, the appearance of new traits is probably accellerating.

The important factors here being loss of ancient selective pressures, and increase in human population.

Traits don't mutate, mutations lead to new traits.
Beneficial can only be defined in terms of selective pressures.

Scientifically we cannot determine a trait as beneficial, until we have first determined a specific selective pressure and secondly made observations and measurements showing a trait to be positively selected for.

[Byblos]

Quite a simplistic view of evolution you have there.
We may not have the same selective pressures, but I have a sneaking suspicion that selective pressures still exist.
And on the other side of the equation the variation of traits and appearance of new traits is probably accellerating at a pace never before seen for the human race.

Such as?

And do you see those new traits mutating beneficially (and how)?

I am sure I said probably, I do not have any examples. The thinking goes as follows. Since we are all born with mutations, and mutations can lead to new traits, and the population is very large, the appearance of new traits is probably accellerating.The important factors here being loss of ancient selective pressures, and increase in human population.

If this were the case (and by no means am I denying it's not), surely we ought to have already seen evidence of that.

Traits don't mutate, mutations lead to new traits.
Beneficial can only be defined in terms of selective pressures.

Here again, can we not account for those selective pressures and trace back whether or not those new traits were as a result of specific mutations giving rise to such traits? Is there any evidence of that?

Scientifically we cannot determine a trait as beneficial, until we have first determined a specific selective pressure and secondly made observations and measurements showing a trait to be positively selected for.

Never mind 'beneficial' then.

[BGoodForGoodSake]

Traits don't mutate, mutations lead to new traits.
Beneficial can only be defined in terms of selective pressures.

Here again, can we not account for those selective pressures and trace back whether or not those new traits were as a result of specific mutations giving rise to such traits? Is there any evidence of that?

Scientifically we cannot determine a trait as beneficial, until we have first determined a specific selective pressure and secondly made observations and measurements showing a trait to be positively selected for.

Never mind 'beneficial' then.

Sure we can, but it is dificult to identify the selective pressures, because these presures need to be there acting on a population/sub-population over several generations.
But looking back one can find traits being selected for.
FoxP2
FoxP2 technical
Genghis Kahn
Lactose Tolerance
Blue eyes
As for traits appearing now, we cannot see because they have just appeared and therefore are undetectable for the time being( Unless we have a database of everyones DNA and a super computer to analyze each persons genetic code, and a fuller understanding of the genome and genes and DNA etc., Unfortunately we have none of these conditions)

I could venture some guesses for selective pressures.
In the United States a high calorie diet is readily available. Previously advantageous traits in this new environment may be the cause of diabeties and obesity among other conditions.

Well that's all I can think of for now .

[Byblos]

Sure we can, but it is dificult to identify the selective pressures, because these presures need to be there acting on a population/sub-population over several generations.

In the absence of clear evidence wouldn't you say then that might be the case of putting the cart before the horse?

But looking back one can find traits being selected for.
FoxP2
FoxP2 technical

I'm not sure how FOXP2 represents a selective pressure. It is a mutation of a trait already selected for (that of speech).

Genghis Kahn

Again, how is that selecting anything? It's just a simple genetic trace up the familial ladder.

Lactose Tolerance

Ah, there's one, thank you. A clear case of adaptation.

Blue eyes

Could be, I don't know. It has no bearing though one way or the other (negative or positive).

As for traits appearing now, we cannot see because they have just appeared and therefore are undetectable for the time being( Unless we have a database of everyones DNA and a super computer to analyze each persons genetic code, and a fuller understanding of the genome and genes and DNA etc., Unfortunately we have none of these conditions)

I could venture some guesses for selective pressures.
In the United States a high calorie diet is readily available. Previously advantageous traits in this new environment may be the cause of diabeties and obesity among other conditions.

Well that's all I can think of for now .

Yes, that's the problem (and why I started asking the questions to begin with ).

[BGoodForGoodSake]

My answer to this is that you asked if there were any cases of new new traits being selected for. And of course the response is that we cannot determine if selection is occuring until after the fact.
So it is not a case of pulling the cart before the horse. It is a case of trying to determine where the horse is going before the tracks are made. We have to wait for the tracks to be made before determining if any selection is occuring.

In the case of FoxP2 there is a variation found in europeans which seems to be selected for as it's occurrance is higher statistically than one would expect if it were a neutral trait. There is a similarily seleted gene in found in asians. Altho the name of it escapes me at the moment. I am sure you would not be surprised to find out that many of the genes found in humans have multiple varieties.

In the case of Genghis Kahn again the occurrance of his Y chromosome in the population is higher statistically than one would expect. If one does some research one would find that being descended from Kahn might have been an advantage in certain parts of the world historically, and conferred economic and social advantages. Also obviously the success of his campaigns seems to have also led to the spread of his verion of the Y chromosome. So through conquest, social and economic advantages his lineage has had a selective advantage in recent history.

In the case of Blue Eyes again the occurrance of this trait is higher statistically than one would expect. It would seem that selection be it sexual or something else altogether has occurred to bestow those born with this trait an advantage in terms of passing down this trait to future generations. I disagree with your assertion that it has no bearing one way or the other (negative or positive). You can only state this if your definition of what is negative or positive is based on a preconceived set of parameters for what is positive or negative. The absolute and scientific and mathmatical definition is not a list of criteria but simply, any trait which is being selected, for any reason, allowing it to be expressed in a greater proportion of the population than what would otherwise be expected given generally accepted statistical models.

Identifying selective pressures in the modern world means navigating through political and social landmines making it difficult for one to just pull a few examples from a hat. But if one were to give it some thought it is possible to come up with a few research topics. Although to make a claim requires that the research be done in advance.

[Murray]

if we did not evolve from all the list of homo's (not a joke), then why were they even there? Why would god pop them into existence? Maybe god created Neanderthals to help boost our immunity, but that does not explain like the 20 other homo's that look near identical to us?

Do you believe that adam and eve were homo rudolfnesis then adapted to homo ergaster, then to homo habulus ect, ect.. .

Or do you believe that god popped like 20 things that almost look identical to us and the killed them off in a couple thousand year span? (for no reason)


Where did they come from? why are they here? why do the earlier ones look so close to monkeys? why did I drink that 40 oz coffee? why why why why why

[kmr]

Yes, selective pressures still exist.... I am by no means an evolutionist, but I do accept the concept of natural selection, it is just that the "selective pressures" have shifted.

[Byblos]

My answer to this is that you asked if there were any cases of new new traits being selected for. And of course the response is that we cannot determine if selection is occuring until after the fact.
So it is not a case of pulling the cart before the horse. It is a case of trying to determine where the horse is going before the tracks are made. We have to wait for the tracks to be made before determining if any selection is occuring.

In the case of FoxP2 there is a variation found in europeans which seems to be selected for as it's occurrance is higher statistically than one would expect if it were a neutral trait. There is a similarily seleted gene in found in asians. Altho the name of it escapes me at the moment. I am sure you would not be surprised to find out that many of the genes found in humans have multiple varieties.

In the case of Genghis Kahn again the occurrance of his Y chromosome in the population is higher statistically than one would expect. If one does some research one would find that being descended from Kahn might have been an advantage in certain parts of the world historically, and conferred economic and social advantages. Also obviously the success of his campaigns seems to have also led to the spread of his verion of the Y chromosome. So through conquest, social and economic advantages his lineage has had a selective advantage in recent history.

In the case of Blue Eyes again the occurrance of this trait is higher statistically than one would expect. It would seem that selection be it sexual or something else altogether has occurred to bestow those born with this trait an advantage in terms of passing down this trait to future generations. I disagree with your assertion that it has no bearing one way or the other (negative or positive). You can only state this if your definition of what is negative or positive is based on a preconceived set of parameters for what is positive or negative. The absolute and scientific and mathmatical definition is not a list of criteria but simply, any trait which is being selected, for any reason, allowing it to be expressed in a greater proportion of the population than what would otherwise be expected given generally accepted statistical models.

Identifying selective pressures in the modern world means navigating through political and social landmines making it difficult for one to just pull a few examples from a hat. But if one were to give it some thought it is possible to come up with a few research topics. Although to make a claim requires that the research be done in advance.

Understood. My extremely limited knowledge of the subject matter aside, it just seems to me like a lot of presuppositions go into identifying the inter-links between selective pressures, mutations, and new traits. We look at data after the fact and make inferences but we're not exactly sure what the exact mechanism is nor its exact pathways. But I rely on you to clear all that up .

[BGoodForGoodSake]

Understood. My extremely limited knowledge of the subject matter aside, it just seems to me like a lot of presuppositions go into identifying the inter-links between selective pressures, mutations, and new traits. We look at data after the fact and make inferences but we're not exactly sure what the exact mechanism is nor its exact pathways. But I rely on you to clear all that up .

For studies trying to correlate a selective pressure with gene distribution the following most likely applies.

Well let's put it this way, the mutation which occurred to create the new trait or version of a trait is faith based on previous observations. Similar to expecting to find a muddy shoe to go along with tracks in the mud. (this is how the following fits into the greater theory)
The conclusion that selection has occurred is in most cases almost uncontroversial. (this is where the science lives)
The selective pressure associated with the selection event is mostly hypothetical. (this is the hypothesis)
The existance of a different trait or mutation is fact. The distribution of the trait is also a fact (this is an observation)

So to apply to a real example.
The gene for blue eyes is relatively young. Must have occurred once and spread throughout the population. (this is how the above fits into the greater theory)
The gene for blue eyes has spread further and wider than one would expect. Distribution vs expectation.(data Analysis)
Perhaps there is sexual selection occurring here. (this is the hypothesis)
All those with blue eyes share the same varience. (observation and fact)