Claim CB101:
Most mutations are harmful, so the overall effect of mutations is
harmful.
Source:
Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master
Books, pp.
55-57.
Watchtower Bible and Tract Society. 1985. Life--How Did It Get
Here? Brooklyn, NY, pg. 100.
Response:
- Most mutations are neutral. Nachman and Crowell estimate around 3
deleterious mutations out of 175 per generation in humans (2000). Of
those that have significant effect, most are harmful, but the
fraction which are beneficial is higher than usually though. An
experiment with E. coli found that about 1 in 150 newly arising
mutations and 1 in 10 functional mutations are beneficial (Perfeito
et al. 2007).
The harmful mutations do not survive long, and
the beneficial mutations survive much longer, so when you consider only
surviving mutations, most are beneficial.
- Beneficial mutations are commonly observed. They are common enough to
be problems in the cases of antibiotic resistance in disease-causing
organisms and pesticide resistance in agricultural pests (e.g., Newcomb
et al. 1997; these are not merely selection of
pre-existing
variation.) They can be repeatedly observed in laboratory populations
(Wichman et al. 1999). Other examples include the following:
- Mutations have given bacteria the ability to degrade nylon
(Prijambada et al. 1995).
- Plant breeders have used mutation breeding to induce mutations
and select the beneficial ones (FAO/IAEA 1977).
- Certain mutations in humans confer resistance to AIDS (Dean et al.
1996; Sullivan et al. 2001) or to heart disease (Long 1994;
Weisgraber et al. 1983).
- A mutation in humans makes bones strong (Boyden et al. 2002).
- Transposons are common, especially in plants, and help to provide
beneficial diversity (Moffat 2000).
- In vitro mutation and selection can be used to evolve substantially
improved function of RNA molecules, such as a ribozyme (Wright and
Joyce 1997).
- Whether a mutation is beneficial or not depends on environment. A
mutation that helps the organism in one circumstance could harm it in
another. When the environment changes, variations that once were
counteradaptive suddenly become favored. Since environments are
constantly changing, variation helps populations survive, even if some
of those variations do not do as well as others. When beneficial
mutations occur in a changed environment, they generally sweep through
the population rapidly (Elena et al. 1996).
- High mutation rates are advantageous in some environments.
Hypermutable strains of Pseudomonas aeruginosa are found more
commonly in the lungs of cystic fibrosis patients, where antibiotics
and other stresses increase selection pressure and variability, than in
patients without cystic fibrosis (Oliver et al. 2000).
- Note that the existence of any beneficial mutations is a
falsification of the young-earth creationism model (Morris 1985, 13).
Links:
Williams, Robert. n.d. Examples of beneficial mutations and natural
selection. http://www.gate.net/~rwms/EvoMutations.html
Williams, Robert. n.d. Examples of beneficial mutations in humans.
http://www.gate.net/~rwms/EvoHumBenMutations.html
References:
- Boyden, Ann M., Junhao Mao, Joseph Belsky, Lyle Mitzner, Anita Farhi,
Mary A. Mitnick, Dianqing Wu, Karl Insogna, and Richard P. Lifton. 2002.
High bone density due to a mutation in LDL-receptor-related protein 5.
New England Journal of Medicine 346: 1513-1521, May 16, 2002.
http://content.nejm.org/cgi/content/short/346/20/1513
- Dean, M. et al. 1996. Genetic restriction of HIV-1
infection and progression to AIDS by a deletion allele of the CKR5
structural gene. Science 273: 1856-1862.
- Elena, S. F., V. S. Cooper and R. E. Lenski. 1996. Punctuated evolution
caused by selection of rare beneficial mutations. Science 272:
1802-1804.
- FAO/IAEA. 1977. Manual on Mutation Breeding, 2nd ed. Vienna:
International Atomic Energy Agency.
- Long, Patricia. 1994. A town with a golden gene. Health 8(1)
(Jan/Feb.): 60-66.
- Moffat, Anne S. 2000. Transposons help sculpt a dynamic genome.
Science 289: 1455-1457.
- Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master
Books.
- Nachman, M. W. and S. L. Crowell. 2000. Estimate of the mutation rate
per nucleotide in humans. Genetics 156(1): 297-304.
- Newcomb, R. D. et al. 1997. A single amino acid substitution converts
a carboxylesterase to an organophosporus hydrolase and confers
insecticide resistance on a blowfly. Proceedings of the National Academy
of Science USA 94: 7464-7468.
- Oliver, Antonio et al. 2000. High frequency of hypermutable
Pseudomonas aeruginosa in cystic fibrosis lung infection.
Science
288: 1251-1253. See also: Rainey, P. B. and R. Moxon, 2000. When
being hyper keeps you fit. Science 288: 1186-1187. See also:
LeClerc, J. E. and T. A. Cebula, 2000. Pseudomonas survival
strategies in cystic fibrosis (letter), 2000. Science 289: 391-392.
- Perfeito, Lilia, Lisete Fernandes, Catarina Mota and Isabel
Gordo. 2007. Adaptive mutations in bacteria: High rate and small
effects. Science 317: 813-815.
- Prijambada, I. D., S. Negoro, T. Yomo and I. Urabe. 1995. Emergence of
nylon oligomer degradation enzymes in Pseudomonas aeruginosa PAO
through experimental evolution. Applied and Environmental
Microbiology 61(5): 2020-2022.
- Sullivan, Amy D., Janis Wigginton and Denise Kirschner. 2001. The
coreceptor mutation CCR5-delta-32 influences the dynamics of HIV
epidemics and is selected for by HIV. Proceedings of the National
Academy of Science USA 98: 10214-10219.
- Weisgraber K. H., S. C. Rall Jr., T. P. Bersot, R. W. Mahley, G.
Franceschini, and C. R. Sirtori. 1983. Apolipoprotein A-I
Milano. Detection of normal A-I in affected subjects and evidence for
a cysteine for arginine substitution in the variant A-I. Journal of
Biological Chemistry 258: 2508-2513.
- Wichman, H. A. et al. 1999. Different trajectories of parallel
evolution during viral adaptation. Science 285: 422-424.
- Wright, M. C. and G. F. Joyce. 1997. Continuous in vitro evolution of
catalytic function. Science 276: 614-617. See also:
Ellington, A. D., M. P. Robertson and J. Bull, 1997. Ribozymes
in wonderland. Science 276: 546-547.
Further Reading:
Harter, Richard. 1999. Are mutations harmful?
http://www.talkorigins.org/faqs/mutations.html
Peck, J. R. and A. Eyre-Walker. 1997. The muddle about mutations.
Nature 387: 135-136.
created 2001-2-17, modified 2008-6-20