Why can creationists give straight answers?

Scott,Hasn't the mutation "limit" been shown to be exceeded experimentally anyway?That is, that the maths that the 1667 beneficial mutation limit was derived from, has been shown to be wrong in studies on other organisms?Not sure if I'm confusing two different things.......Mark------------------
Occam's razor is not for shaving with.

Scott,Thanks for the reply.So basically, Haldanes "limit" of 1 beneficial allele fixed/300 generations has been shown false.In that case the model has been clearly found wanting, so (rhetorical question imminent) how can you form an argument claiming a falsification, when the model you get that falsification from, is shown to be faulty?IMO, Scott, you needn't have asked the question "do we know that 1667 beneficial mutations weren't enough to separate man from chimps?" Since the question is already moot.Whilst I'm at it, it has just occurred to me that it's 1667 ben. mut. to go from a common ancestor of humans & chimps, to humans & chimps. This assumes that chimps ARE the common ancestor of man, & have had no beneficial mutations fixed themselves. This means you should roughly double the figure, since the chimps are getting 1667 be. muts. as well, not just humans. So wouldn't there have been 3334 fixed beneficial alleles in the two species from divergence (according to Haldane in '57), or has this been taken into account?Hope that made sense Mark------------------
Occam's razor is not for shaving with.

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Originally posted by Peter:
Couldn't you get from a common ancestor to chimps & man
with 1667/2 (if 1667 is an ok number ... dunno where it
came from but hey ...)?

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If the 1667 were split in half (I know, I know it's odd),
but where in different locations in the two lines,
you'd end up with 1667 differences.

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So from a common (and different genetically) ancestor, you would
have to split the 1667 amongst the two lines.

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Or however many mutations were actually accumulated.

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The 1667 fixed beneficial mutations is a limit set by Haldanes 1957 model. 1 fbn/300 generations. Rather than an estimated difference between humans & chimps. Creationists think this too low, but are unable to say why.My point above was, if human/chimp divergence was 5 mya (or whatever), & Haldanes model allows 1667 fbm in that time, then surely the chimp clade gets 1667 fbn (or thereabouts) as well as us. This means that, according to Haldane in '57, there are 1667*2 = 3334 fbm (not /2) allowed as differences between humans & chimps. It's 1667 fbm each back to their most recent common ancestor, therefore 3334 fbm mutations relative to each other.As Scott laboriously points out whenever this comes up, Haldane himself recognised the weakness of his model, in that it was based on estimated assumptions, & not derived data. Today, his the maximum number of fbm has been shown to have have been exceeded experimentally.Hope this helps.Mark------------------
Occam's razor is not for shaving with.

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Originally posted by Fred Williams:

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The reason I have to re-ask over and over again is because you refuse to see the point I am trying to make. I’ll give it one last shot. Say a specific base-pair site on a chimp has an SNP where 50% of the population has an ‘A’, and 50% of the population has a ’G’. The corresponding site on human has the same distribution. If we assume Hardy-Weinberg equilibrium (H-W specifically deals with alleles, but it applies equally well to haplotypes such as my example above) then the shared ancestor would have had the same ratio. Thus, this would represent a site that does not represent a difference between the two species. However, if we do a direct sequence-to-sequence comparison between chimps & humans, we have a 50% chance we will log a difference where there is no difference. If the SNP ratio is 75% ‘A’ and 25% ‘G’, the odds are 3/8 (.375) that we will incorrectly log a difference. The point is, SNPs introduce error into these difference estimations. It would be very difficult to remove the SNP-induced errors with precision, but its impact can be reasonably estimated if we have a good idea of the average distribution of SNPs and the ratio of SNPs to the genome portion being compared.

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My point all along is that a precise difference calculation requires accounting for the noise introduced by SNPs. I will again stress that I realize that this SNP noise has not been directly removed, or even accounted for via estimations, when difference estimations have been made. When I argued that scientists were referring to fixed differences when they talk of differences that separate chimp/human, I was stating that I assumed they knew that SNPs inflict noise that distorts the difference estimation to some unknown extent, but must be negligible enough to ignore. I admitted this sentence was confusing, but I still stand by it. If a scientist tells us there is a 1% difference between chimps and man, we must assume these differences pertain to fixed sites, and assume the SNP impact is negligible.

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Good question, one that I will leave to Scott to answer in depth, if I may.That said...Firstly, if you have ANYTHING in Hardy Weinberg equilibrium, then it's an allele. It MAY be the result of an SNP, but not necessarily (no biggie). Therefore, assuming you can identify the different (homologous) alleles, who cares? As long as you don't mix them up, it shouldn't make much difference. Given that the coalescent point of two homologous alleles is likely to be after speciation, the derived phylogeny (inter-species) should be identical.There are exceptions that spring to mind, alpha/beta heamaglobins for example, that are extant in both humans & chimps (coalescence occurred before speciation). In this case, choose which allele from which to infer a phylogeny from, ie don't use alpha from humans & beta from chimps. If you can't tell the difference between alleles, then there's not likely to be an appreciable affect on any derived phylogeny, is there?Regarding SNPs...... Wouldn't it therefore be sensible to arrive at a consensus sequence before performing the analysis? What I mean by this, is to take (for the sake of argument) 100 sequences from humans, 100 from chimps, then orangutans etc. in order to eliminate SNPs. That is, if 99 samples say A at a particular locus, & one says G, then G can be thrown out, & A taken as the consensus for that loci.Mark------------------
Occam's razor is not for shaving with.

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Originally posted by SLPx:

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Originally posted by mark24:
Fred:
My point all along is that a precise difference calculation requires accounting for the noise introduced by SNPs...

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Good question, one that I will leave to Scott to answer in depth, if I may.

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Sorry to disappoint - but there was no need to go into any depth - red herrings and all. One thing - informed cretins know that '% differences' are not meant to be "precise"...

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Regarding SNPs...... Wouldn't it therefore be sensible to arrive at a consensus sequence before performing the analysis? What I mean by this, is to take (for the sake of argument) 100 sequences from humans, 100 from chimps, then orangutans etc. in order to eliminate SNPs. That is, if 99 samples say A at a particular locus, & one says G, then G can be thrown out, & A taken as the consensus for that loci.

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In a perfect world, sure. Sequencing is EXPENSIVE, even if you have your own sequencers (around $125,000 and up), reagents are on the order of 300-500 dollars for 100 or so reactions...

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However, phylogeny analysis does not really need consensus sequences to work. Consensus sequences would provide greater resolutiom and stronger results in most cases, but if your locus contains enough phylogenetically informative sites, it doesn't matter.

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I figured as much re. Not necessary to eliminate SNPs.For the benefit of creationists, here’s why.When performing phylogenetic analysis, you are deriving a divergence (coalescence) tree of XX number of organisms. An SNP in a gene that appeared a generation ago should still return the same tree as the fixed allele. Even if the SNP occurs at a phylogenetically informative site, providing you have enough of those sites, it won’t make an appreciable difference.Mark------------------
Occam's razor is not for shaving with.

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Originally posted by Randy:

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BTW which of Noah's children or daughters-in-law do YECs think was the leper? I don't see how else the disease could have survived the worldwide flood. Armadillos are the only animal carrier and they die pretty quickly when they get it so I don't think they could have gotten from the middle east to Texas if infected.

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Randy

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Same goes for syphilis, gonorrhoea (sp?), etc.In fact, we might ask was it Adam, Eve, or both, that had the above?Mark------------------
Occam's razor is not for shaving with.