How would you deal with the fact that chimps and humans have only a 1.5% difference in DNA?
i have previously dealt with this issue on this board, but it was several years ago...so here we go again
first, there are claims as high/low as 99/1% similarity/difference...one study claims 98.77% similarity
second, your 1.5% figure has been known to be in error for several years (at least 4yrs), but as usual, they don't withdraw the literature claiming that it stays because it was what was *known* at the time...nor do they blast the headlines like they did when they first made the claim particularly if the numbers go backward (ie, look worse than the original claims, look in any way weaker in support of evolution) so that they can preserve the paradigm
so people keep on quoting and posting bogus info
the figure now stands at 5% difference (95% similarity, though some still fudge it up to 96% similarity)
the percentage of difference may yet grow because there is still a lot that we don't understand (ie, *junk* dna, etc)
but lets just suppose for a moment that the difference was to go down/up to 90/10% or even 80/20%...the evolutionary faithful would still claim that the similarity is incredible and is clear evidence of shared ancestry...and they would still claim that chimps are our *closest relatives*
that said, now lets take it back to the oft (falsely) claimed 1.5%...1.5% of ~3billion base pairs in the human genome (and lets assume for a moment an identical number for the chimp genome, which is also false, but...) is still 45m bp difference
now do the math...you will find that the alleged 6-7my that they claim have passed since the divergence between chimps, humans, and the alleged (but UNKNOWN) *common ancestor* is not nearly enough time for the needed mutations to occur (at least not in any uniformitarian or gradualistic scenario)
10my isn't enough, 100my isn't enough
don't forget that mutations are relatively rare, most are harmful, many are *neutral,* and only a very few are thought to be *beneficial* (and not one of those claimed to be beneficial has been shown to be purely so...there is always a tradeoff, and all of them are controversial as to their actual beneficiality...ie, sickle cell anemiacs have a resistance to malaria...but they forget to tell us that 25% of sickle cell anemiacs will DIE of their affliction...hardly purely beneficial...and all of these *beneficial* mutations are a result of a LOSS of information)
so...since those don't work (uniformity and gradualism), in steps punk eek, punc eq, punctuated equilibrium to save the day...but if you've got all these unpredictable great leaps, hopeful monsters going on, then you can't calculate very well anymore because uniformity is the dustbin
anyway, the problem with the 1%, 1.33%, 1.4%, 1.5% claims is that they didn't (perhaps couldn't) look far enough...their comparisons were limited to *nt substitutions* only...now that more study has been done, they realize that *indels* account for more than twice as many differences as substitutions
then there is evidence building that heritable traits are not limited to genetic activity but that other cellular components may also figure in...we have a long way to go on this yet...we may need to revise mendel's long standing work, and we will almost certainly need to add to it in terms of what contributes to heritability
Doesn't this alone point to a link?
hardly...i mean, there is a possibility in one sense that it points toward an evolutionary scenario, but on the other hand, there are many conflicts that still need to be overcome to make the darwinian hypothesis even a remote possibility...and it certainly doesn't in any way *necessarily* point to an evolutionary link
the evidence fits just as well (actually much better) with a common designer scenario as it does with a common ancestor scenario
evolution does not have the upper hand except in arguments from authority (not the strongest argument in terms of logic) simply because they have more authorities (believers :-)...not because they have more evidence...we all have the same evidence; the issue is how we interpret the evidence and the worldview, bias, preconceptions that we bring to the table
in short, it depends on how you conduct the study, what you look at, and how you interpret your findings
study the *differences* one way (a much more limited way) and you will come up with between 1 and 1.5% difference...study it another way (much deeper and broader, but still far from *comprehensive*) and you will come up with more than 3x as many differences
it's what's missing between the human and chimp genomes that makes a bigger difference than the differences between what is there :-)
below are some references, links, and quotes for your perusal...from evolutionary guys, in highly evolutionary biased journals
Britten, R.J. 2002. ?Divergence between samples of chimpanzee and human DNA sequences is 5% counting indels.? Proceedings National Academy Science 99:13633-13635.
full text Britten, R.J., Rowen, L., Williams, J. and Cameron, R.A., Majority of divergence between closely related DNA samples is due to indels, Proc. Nat. Acad. Sci. USA 100(8):4661?4665, 2003.
full text There are 25 chimp BAC sequences that we have studied. Of these, 14 can be aligned nearly from end to end with regions of the human genome, showing typical sequence divergence of 1-2% attributable to base substitutions. The remaining 11 BAC sequences are not easily aligned for their whole length.
The fraction of CpGs that show differences between human and chimp DNA ranges from 13% to 20%.
but you evolutionary guysngals are welcome to keep the faith :-)