Mutation & New Information
The theory needs a source of genuinely new genetic information: new genes, new protein folds, new systems. Textbooks name random mutation, sifted by natural selection. How well does the evidence hold up?
Genetics · Biochemistry · Information theory
Mutation and selection clearly tune and break existing genes. That is observed and repeatable. Whether they can build new protein folds and multi-part systems has not been shown. It is an extrapolation from small changes.
The reasoning behind each grade is in Explore, one claim card at a time.
Mutations modify existing genesObserved in the lab, measured and replicated.
Mutations originate new folds & systemsInferred from small changes, not yet observed.
The pillar's central word, information, is used for both a change in an existing gene and the origin of a new one. Most of the disagreement on these cards turns on keeping the two apart.
From what mutation and selection have been seen to do, over decades, to what they are said to have done over the history of life.
- 4 clear · 3 possible
- 3 clear · 2 possible
- 1 possible
Both readings are checked. How it works →
Every other pillar depends on this one. Natural selection can only choose among variations that already exist, so the theory needs a source of new ones, and of genuinely new information: new genes, new protein folds, new molecular machines. The Modern Synthesis names random mutation as that source.
The three claim cards below take the argument in order. The first asks what mutation and selection have actually been seen to do. The second examines the best-known route to novelty, gene duplication followed by divergence. The third asks how rare working protein sequences are, the number on which the whole question turns.
Claim cards
- № 4.01“Random mutation plus natural selection produces new genetic information.”What have mutation and selection actually been seen to do? Tune and break existing genes, clearly. Build new ones, not yet.4BD
- № 4.02“Gene duplication followed by divergence creates genes with new functions.”A spare copy of a gene is said to be free to mutate into something new. There are striking cases. The question is what they show.3BD
- № 4.03“Functional protein folds are common enough for random mutation to find them.”How many of all possible protein sequences actually work? Published estimates differ by more than sixty orders of magnitude, and the theory depends on the answer.4BD
Primary literature
- Blount ZD, Barrick JE, Davidson CJ, Lenski RE. “Genomic analysis of a key innovation in an experimental Escherichia coli population.” Nature 489:513–518 (2012).Cited in № 4.01B
- Blount ZD, Borland CZ, Lenski RE. “Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli.” PNAS 105:7899–7906 (2008).Cited in № 4.01B
- Carvunis A-R, et al. “Proto-genes and de novo gene birth.” Nature 487:370–374 (2012).Cited in № 4.03C
- Chen L, DeVries AL, Cheng C-HC. “Evolution of antifreeze glycoprotein gene from a trypsinogen gene in Antarctic notothenioid fish.” PNAS 94:3811–3816 (1997).Cited in № 4.02B
- Keefe AD, Szostak JW. “Functional proteins from a random-sequence library.” Nature 410:715–718 (2001).Cited in № 4.01, № 4.03C
- Lynch M, Conery JS. “The evolutionary fate and consequences of duplicate genes.” Science 290:1151–1155 (2000).Cited in № 4.02B
- Lynch M. “Simple evolutionary pathways to complex proteins.” Protein Science 14:2217–2225 (2005).Cited in № 4.02C
- Näsvall J, Sun L, Roth JR, Andersson DI. “Real-time evolution of new genes by innovation, amplification, and divergence.” Science 338:384–387 (2012).Cited in № 4.02B
- Negoro S, et al. “X-ray crystallographic analysis of 6-aminohexanoate-dimer hydrolase.” J. Biol. Chem. 280:39644–39652 (2005).Cited in № 4.01B
- Ohno S. Evolution by Gene Duplication. Springer (1970).Cited in № 4.01, № 4.02C
- Reidhaar-Olson JF, Sauer RT. “Functionally acceptable substitutions in two α-helical regions of λ repressor.” Proteins 7:306–316 (1990).Cited in № 4.03B
- Tokuriki N, Tawfik DS. “Protein dynamism and evolvability.” Science 324:203–207 (2009).Cited in № 4.03C
- Zhang J. “Evolution by gene duplication: an update.” Trends in Ecology & Evolution 18:292–298 (2003).Cited in № 4.02C
- Axe DD. “Estimating the prevalence of protein sequences adopting functional enzyme folds.” J. Mol. Biol. 341:1295–1315 (2004).Cited in № 4.01, № 4.03C
- Behe MJ, Snoke DW. “Simulating evolution by gene duplication of protein features that require multiple amino acid residues.” Protein Science 13:2651–2664 (2004).Cited in № 4.02C
- Behe MJ. “Experimental evolution, loss-of-function mutations, and ‘the first rule of adaptive evolution’.” Quarterly Review of Biology 85:419–445 (2010).Cited in № 4.01B
- Behe MJ. Darwin Devolves. HarperOne (2019).Cited in № 4.01C
- Durston KK, Chiu DKY, Abel DL, Trevors JT. “Measuring the functional sequence complexity of proteins.” Theoretical Biology and Medical Modelling 4:47 (2007).Cited in № 4.03C
- Gauger AK, Axe DD. “The evolutionary accessibility of new enzyme functions: a case study from the biotin pathway.” BIO-Complexity 2011(1):1–17 (2011).Cited in № 4.02C
- Meyer SC. Signature in the Cell. HarperOne (2009).Cited in № 4.03C
- Sanford JC. Genetic Entropy. FMS Publications, 4th ed. (2014).Cited in № 4.01C
Source grades are provisional. The Evidence Evaluator (next phase) will publish a full, challengeable evaluation for each.
Mutate a working “gene”
A sentence stands in for a gene, with words as its functional parts. Each mutation changes one random letter. Turn on selection to keep only mutations that leave every word readable. See whether selection preserves meaning or builds new meaning.
| Mutations attempted | 0 |
| Words broken | 0 |
| Removed by selection | 0 |
| New real words formed | 0 |
This is an analogy, and analogies have limits. Real genes have some redundancy, and real selection acts on whole organisms. Even so, the lab shows a real distinction: keeping function is different from creating it. For real codons and amino acids, try the DNA explorer in the Probability Lab.