Why is evolution so controversial?

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I still have no idea what argument he thinks he's making about linkage disequilibrium, but whatever it is, it's wrong. There's nothing about human LD that is at all suggestive of a recent origin for humans.

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I disagree, the process of crossing over will degenerate linkage between genes from generation to generation. Hundreds of thousands of years will dissolve links between genes involved in recombination. A young genome will exhibit high orders of linkage disequilibrium an older genome would not.

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Speculate about what? Your summary of the claims of unidentified people? Make an argument and then we can discuss it. Right now you seem to be arguing both that there's been lots of selection in recent human history and no selection in recent human history.

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The findings are correct by Hawks and there is an apparent acceleration in recent evolution of humans, about 100 times faster than in the past.Your claim that the paper was mistaken in its conclusion based on method. Here is a citation about recent selective sweeps not being relavent in recent human history (~250,000 years). If this is true, the argument that you make about the methodology might be false. Your opinion although informed seems wrong.

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Admixture increases LD, after which it declines again.

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Also I might add that admixture may not affect LD significantly when very similar genetic populations remix.

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Sorry, but this makes no sense. Hawks's claim is that positive selection, detected via selective sweeps, has become very frequent in recent human history.

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You claim there is a problem in methodology in detecting selective sweeps earlier than 20,000 years, but here is the data set in graphic form: Sorry for the bad detail look at it here: http://www.johnhawks.net/...celeration/accel_story_2007.htmlThis is from Hawks web site it looks to me like there is no discordance in data, look at ten thousand years (first point is 20,000 years), the trend is already started to decline. The downward trend does look like it continuos uniformly threw and past 20,000 years.You continually move the goal posts, maybe you can claim that 10,000 years has got problems for detection now. If there was a problem of method you would expect an anomaly around 20,000 years (there is none). You are entitled to any opinion concerning methodology you like, but it is just an opinion.

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Hernadez et al claim that there have been very few classic selective sweeps in recent human history. While the second paper doesn't flat-out contradict the first, it certainly argues in the nearly opposite direction. By introducing the 2nd paper, you're supporting my opinion, not undermining it.

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No I am not you are wrong.Edited by zaius137, : No reason given.Edited by Admin, : Provide a white background for the image.

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First, that plot is of when the "selection" is supposed to have started, not when it contributed to the genetic signature -- selection goes on for a fairly long time. Second, that plot (which I'd forgotten) in fact looks like an almost perfect illustration of the loss of power for older and older events.

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Please explain to me is supposed to have stared . In my simple reasoning, I assume you are looking for a signature in the genome dictating the start of a selection. You see, you can not know any direct information about the selection or duration, only its result. I see all requirements met by Hawks methodology.I would also like your patient explanation about selection goes on for a fairly long time in view of my previous statement (you can not know any direct information about the selection or duration).

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What on earth are you talking about? I never suggested that long-haplotype tests fail abruptly after 20,000 years. They steadily lose power for older and older sweeps, and beyond roughly 20,000 years the power is low enough that you're not going to detect much. Why should there be an anomaly 20,000 years ago?

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I never said that the long-haplotype tests fail abruptly after 20,000 years. I asked you to look at the trend after 10,000 years, a year even by your own definition does not come into question.

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That's some pretty impressive logic you've deployed there.

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We are just getting to the logic part

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Second, that plot (which I'd forgotten) in fact looks like an almost perfect illustration of the loss of power for older and older events.

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Either that or it is telling you what Hawks is suggesting.

I am sure sfs has gone threw Hawks’s null hypothesis. I think it will put a exclamation on my point. I do not usually do this but I will let the author explain:

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We took several different approaches, testing predictions on different kinds of data. For one thing, if the null hypothesis were true, then there should be a whole lot more selected mutations that have already reached or approached fixation, than the relatively small number that we see still varying in human populations. So to test the null hypothesis, we should look for evidence of these fixed selected substitutions.
That's exactly what we did -- we looked at other means of assessing the number of recently fixed and near-fixed variants. http://www.johnhawks.net/...celeration/accel_story_2007.html

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On the bottom of this graph, we have the European age distribution of variants in our window. This should represent a small fraction of the total number that have happened across this time period. But you can see from this graph, that if the rate was constant, the total number should be very, very large -- since we are looking at 10-generation bins, here we have around 150 predicted substitutions every 10 generations, or around 1/2 per year. Most of these should be way above our window, in fact, as we go back toward 40,000 years ago, almost all should be close to or at fixation.http://www.johnhawks.net/...celeration/accel_story_2007.html

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In other words, from what sfs does accept by Hawks’s method, the high rate of selection observed now (current levels) shows an impossible number of selections, if extrapolated to the past.Hawks is right sfs is clearly wrong.Edited by zaius137, : No reason given.

Thanks RAZD..You the man, woman, thing...

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I see you folks going on and on about various aspects of population dynamics, with you trying to set the groundwork for a 6,000 year old modern human. And failing.

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I admit there is no way to get to 6000 years from here. Sorry to disappoint you. Let us move on in the discussion, if needed radio dating. My apologies to all.

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If you multiply the curve for "Predicted fixed and near-fixed variants (constant rate model)" by an exponential decay curve for (correctly modeling) the loss of long sections over time you will get a curve that fits the data better than the "Predicted fixed and near-fixed variants (demographic model)" and that this would show that sfs is correct.

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Possibly (I think most participants have had enough), as I understand it, sfs is arguing discrepancies in the methodology. When something shakes up the little world that some PhDs occupy, the first thing that goes is methodology (no matter how well accepted). You see, by my own admission, I have no skin in the game here. When was the last time you witnessed a Creationist supporting a evolutionist findings? Hawks is very set in his worldview of evolution. What gets me is the backdoor critics that rear their heads when something in science is about to change.I can not prove that sfs is wrong the same way sfs can not prove Hawks is wrong. If so, write the paper so we will read it.

Genomicus...It has been a while, please let us take up one point at a time so we can all participate.Your first point is?

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When I get results that contradict expectation, the first thing I think is: "I must have done something wrong."
Why should I think otherwise?

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Am I wrong to think that is procedure and not methodology.Methodology: Methodology is the systematic, theoretical analysis of the methods applied to a field of study. wikiProcedure: Instructions or recipes, a set of commands that show how to prepare or make something. wiki

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Why should any PhD be shaken by claims that are founded on false assumptions? There is absolutely no reason why any population should grow at the same rate throughout history.

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What discussion are you referring to? Post # would help.

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And to keep this post directly tied into the theme of the thread: Evolution is so controversial because a small number of folks won't accept it, for religious, not scientific, reasons, and run around making a big stink. They have no evidence supporting their positions, as you are demonstrating, but make up for that lack by religious zeal and stubborn denial of the evidence that contradicts their beliefs.

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Really? I have spent a lot of time running down the evidence for evolution. Science is based on evidence measurable by the scientific method. I am a firm believer in empirical evidence. I would like to examine the following:Darwin’s Galapagos finches : This seems to be a trait influenced by epigenetic changes. Epigenetic changes involve switching on or off gene segments by chemical tags acting on the genome and not actually changing the genetic code. Well, where did the coding segment for the trait originate?
How would Darwinian evolution explain epigenetic changes? The DNA segment not used for long stretches of time is not culled from the genome. Should it not be identifiable as a non selection in a allele cluster? Swept from the genome by a classic selective sweep.