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发表于 2011-7-7 01:34 AM
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Claim CB100:
Evolution requires mutations, but mutations are rare.
Source:
Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master Books, pg. 55.
Response:
1.Very large mutations are rare, but mutations are ubiquitous. There is roughly 0.1 to 1 mutation per genome replication in viruses and 0.003 mutations per genome per replication in microbes. Mutation rates for higher organisms vary quite a bit between organisms, but excluding the parts of the genome in which most mutations are neutral (the junk DNA), the mutation rates are also roughly 0.003 per effective genome per cell replication. Since sexual reproduction involves many cell replications, humans have about 1.6 mutations per generation. This is likely an underestimate, because mutations with very small effect are easy to miss in the studies. Including neutral mutations, each human zygote has about 64 new mutations (Drake et al. 1998). Another estimate concludes 175 mutations per generation, including at least 3 deleterious mutations (Nachman and Crowell 2000).
Links:
Harter, Richard. 1999. Are mutations harmful? http://www.talkorigins.org/faqs/mutations.html
References:
1.Drake, J. W. et al. 1998. See below.
2.Nachman, M. W. and S. L. Crowell. 2000. Estimate of the mutation rate per nucleotide in humans. Genetics 156(1): 297-304.
Further Reading:
Drake, J. W., B. Charlesworth, D. Charlesworth, and J. F. Crow. 1998. Rates of spontaneous mutation. Genetics 148: 1667-1686. (technical) |
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