Phenotype space

Figure 12. The error threshold of replication and mutation in phenotype space. The genotypic error threshold approaches zero in the case of selective neutrality. Despite changing genotypes a phenotype may be conserved in evolution whenever it has higher fitness than the other phenotypes in the population. The concept of error threshold can easily be extended to competition between phenotypes. The distribution of phenotypes is stationary provided the error rate does not exceed the maximum value pmax which is a function of the mean fraction of nearest neighbors, X, and the superiority of the master phenotype, a. The illustration shows the position of the phenotypic error threshold in the X, p plane. Selective neutrality allows more errors to be tolerated and pmax increases accordingly with increasing X. If X approaches the inverse superiority, X — a-1, the tolerated error may grow to pmax = 1, and this means the phenotype will never be lost, no matter how many errors are made in replication.

Fig. 2.3. Sequence space and genotype - phenotype mappings. Mapping genotypes onto phenotypes and into fitness values. The sketch shows a map from sequence (or genotype) space onto phenotype space, as described in the text, and further into the real numbers resulting in fitness values assigned in two steps to the indi-...

Boghigian BA, Lee K, Pfeifer BA (2009) Computational analysis of phenotypic space in heterologous polyketide biosynthesis - applications to Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae. J Theor Biol 262 197-207 Borisova SA, Zhao L, Melancon 1C, Kao CL, Liu HW (2004) Characterization of the glycosyl-transferase activity of desVll analysis of and implications for the biosynthesis of macroUde antibiotics. J Am Chem Soc 126 6534-6535... 

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