title: Confidence interval for the number of selectively neutral amino acid polymorphisms.
abstract: A statistical approach to the analysis of DNA sequences has been developed, which provides a confidence interval estimate for the proportion of naturally occurring amino acid polymorphisms that are selectively neutral. When applied to the gnd gene coding for 6-phosphogluconate dehydrogenase in a sample of seven natural isolates of Escherichia coli, the method indicates that the proportion of observed amino acid polymorphisms that are selectively neutral is unlikely to be greater than 49% (upper 95% confidence limit). On the other hand, the observations are also consistent with a model in which all of the observed amino acid substitutions are mildly deleterious with an average selection coefficient approximating 1.6 X 10(-7). Various models for the distribution of configurations at silent sites are also investigated.
authors.forename: S A
authors.initials: SA
authors.lastname: Sawyer
authors.forename: D E
authors.initials: DE
authors.lastname: Dykhuizen
authors.forename: D L
authors.initials: DL
authors.lastname: Hartl
mesh_terms: D000596:Amino Acids / Q000235:genetics*; D003062:Codon / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D008957:Models, Genetic; D009154:Mutation; D010734:Phosphogluconate Dehydrogenase / Q000235:genetics; D011110:Polymorphism, Genetic; D012641:Selection, Genetic
chemical_list: D000596:Amino Acids; D003062:Codon; D004269:DNA, Bacterial; D010734:Phosphogluconate Dehydrogenase