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SCOTT L. PAGE
The following papers:J. C. Fay, G. J. Wyckoff and C.-I. Wu: Positive and Negative Selection on the Human Genome, Genetics 158, 1227-1234. 2001.andSexual Recombination and the
Power of Natural Selection
William R. Rice* and Adam K. Chippindale
2001 Science 294:555-559
severely impact the various claims of creationists who insist that because of 'Haldane's dilemma', among other things, human evolution from an ape-like ancestor is impossible.This 'conclusion' is premised primarily on personal opinions, for there is, at present, no information at all regarding the numbers of fixed beneficial mutations required to explain various adaptations and traits in extant organisms.Nonetheless, the argument regarding the human question goes something like this:According to an extrapolation of Haldane's 1957 paper, no more than 1667 fixed, beneficial mutations could accrue in the lineage leading to humans from an ape-like ancestor.1667 is too few to account for this (unsupported assertion), therefore, humans must not have evolved at all.According to the first paper mentioned, the number is off - way off. We cannot blame Haldane - he was working more than a decade before and sequence data was available to him.
This paper demonstrates that there have been approximately one beneficial allele substitution every 200 years since the split between Old and New world primates some 30 million years ago.This amounts to 150,000 in 30 million years. The estimated split between the lineage leading to humans from that leading to chimps is around 5-6 million years ago.We'll go with 5. That allows for some 25,000. That is 14 times what was allowed under Haldane's model.Considering the fact that HGP analysis and others put the total gene number in the human genome at between 30 and 60,000, and if we consider that each of these genes may be influenced by at least one regulatory region, 25,000 substitutions - by anyone's standards - should be seen as more than enough to acocunt for the differences.Of course, since it is a fact that it has not been shown that 1667 fbms is too few, I am still not convinced that it cannot be explained by the lower number.I suppose it all rests on one's point of view, a! nd whether or not one is willing to accommodate new discoveries into their lexicon.From the second paper, emphases mine:"Our results experimentally verify a counteracting advantage of recombining compared to clonal lineages: reduced accumulation of harmful mutations and increased accumulation of beneficial mutations. The magnitude of this benefit will accrue over geological timeand promote the superior persistence of recombining lineages at both the
level of species within communities (clonal versus sexual species) and genes within chromosomes (nonrecombining Y-linked versus recombining X-linked genes)."I don't think that needs any more explanation.Comments appreciated.
[Administrator: this was edited to remove invalid code and replace with bold to show where the author wished emphasis.]
[ January 24, 2002: Message edited by: Administrator ]
The following papers:J. C. Fay, G. J. Wyckoff and C.-I. Wu: Positive and Negative Selection on the Human Genome, Genetics 158, 1227-1234. 2001.andSexual Recombination and the
Power of Natural Selection
William R. Rice* and Adam K. Chippindale
2001 Science 294:555-559
severely impact the various claims of creationists who insist that because of 'Haldane's dilemma', among other things, human evolution from an ape-like ancestor is impossible.This 'conclusion' is premised primarily on personal opinions, for there is, at present, no information at all regarding the numbers of fixed beneficial mutations required to explain various adaptations and traits in extant organisms.Nonetheless, the argument regarding the human question goes something like this:According to an extrapolation of Haldane's 1957 paper, no more than 1667 fixed, beneficial mutations could accrue in the lineage leading to humans from an ape-like ancestor.1667 is too few to account for this (unsupported assertion), therefore, humans must not have evolved at all.According to the first paper mentioned, the number is off - way off. We cannot blame Haldane - he was working more than a decade before and sequence data was available to him.
This paper demonstrates that there have been approximately one beneficial allele substitution every 200 years since the split between Old and New world primates some 30 million years ago.This amounts to 150,000 in 30 million years. The estimated split between the lineage leading to humans from that leading to chimps is around 5-6 million years ago.We'll go with 5. That allows for some 25,000. That is 14 times what was allowed under Haldane's model.Considering the fact that HGP analysis and others put the total gene number in the human genome at between 30 and 60,000, and if we consider that each of these genes may be influenced by at least one regulatory region, 25,000 substitutions - by anyone's standards - should be seen as more than enough to acocunt for the differences.Of course, since it is a fact that it has not been shown that 1667 fbms is too few, I am still not convinced that it cannot be explained by the lower number.I suppose it all rests on one's point of view, a! nd whether or not one is willing to accommodate new discoveries into their lexicon.From the second paper, emphases mine:"Our results experimentally verify a counteracting advantage of recombining compared to clonal lineages: reduced accumulation of harmful mutations and increased accumulation of beneficial mutations. The magnitude of this benefit will accrue over geological timeand promote the superior persistence of recombining lineages at both the
level of species within communities (clonal versus sexual species) and genes within chromosomes (nonrecombining Y-linked versus recombining X-linked genes)."I don't think that needs any more explanation.Comments appreciated.
[Administrator: this was edited to remove invalid code and replace with bold to show where the author wished emphasis.]
[ January 24, 2002: Message edited by: Administrator ]