Claim CB121:
J. B. S. Haldane calculated that new genes become fixed only after 300
generations due to the cost of natural selection (Haldane 1957). Since
humans and apes differ in 4.8 × 107 genes, there has not been
enough time for difference to accumulate. Only 1,667 nucleotide
substitutions in genes could have occurred if their divergence was ten
million years ago.
Source:
ReMine, Walter J., 1993. The Biotic Message, St. Paul Science, Inc.
Response:
- Haldane's "cost of natural selection" stemmed from an invalid
simplifying assumption in his calculations. He divided by a fitness
constant in a way that invalidated his assumption of constant
population size, and his cost of selection is an artifact of the
changed population size. He also assumed that two mutations would take
twice as long to reach fixation as one, but because of sexual
recombination, the two can be selected simultaneously and both reach
fixation sooner. With corrected calculations, the cost
disappears (Wallace 1991; Williams n.d.).
Haldane's paper was published in 1957, and Haldane himself said, "I am
quite aware that my conclusions will probably need drastic revision"
(Haldane 1957, 523). It is irresponsible not to consider the revision
that has occurred in the forty years since his paper was published.
- ReMine (1993), who promotes the claim, makes several invalid
assumptions. His model is contradicted by the following:
- The vast majority of differences would probably be due to genetic
drift, not selection.
- Many genes would have been linked with genes that are selected and
thus would have hitchhiked with them to fixation.
- Many mutations, such as those due to unequal crossing over, affect
more than one codon.
- Human and ape genes both would be diverging from the common ancestor,
doubling the difference.
- ReMine's computer simulation supposedly showing the negative
influence of Haldane's dilemma assumed a population size of only six
(Musgrave 1999).
Links:
Williams, Robert, n.d. Haldane's dilemma.
http://www.gate.net/~rwms/haldane1.html
References:
- Haldane, J. B. S., 1957. The cost of natural selection. Journal of
Genetics 55: 511-524.
- Musgrave, Ian, 1999. Weasels, ReMine, and Haldane's dilemma.
http://www.talkorigins.org/origins/postmonth/sep99.html
- ReMine, Walter J., 1993. The Biotic Message, St. Paul Science, Inc.
- Wallace, Bruce, 1991. Fifty Years of Genetic Load - An Odyssey.
Cornell University Press. See particularly Chapters 5, 6, 8, and 9.
- Williams. (See above)
created 2001-2-17, modified 2006-6-8