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. 1973 Dec;116(3):1130–1135. doi: 10.1128/jb.116.3.1130-1135.1973

Integration Efficiencies of Spontaneous Mutant Alleles of amiA Locus in Pneumococcal Transformation

Gérard Tiraby 1, Michel A Sicard 1
PMCID: PMC246466  PMID: 4148095

Abstract

The distribution of integration efficiencies of independent mutations spontaneously occurring in the amiA locus was determined in two strains of pneumococcus. Strain Cl3 integrates genetic markers with different efficiencies during transformation, whereas strain 401, isogenic with strain Cl3, does not discriminate between markers and integrates all markers with the same high efficiency. The discriminating strain Cl3 gives rise to spontaneous mutations in the locus amiA, which fall into four classes with respect to their individual integration efficiencies. Mutations with a low efficiency of integration are equal in number to mutations with a high efficiency. Mutations from the two other classes corresponding to intermediate and very high efficiencies are about five times less frequent. The same four classes were also found among amiA mutants spontaneously occurring in strain 401. However, the two distributions of integration efficiencies of amiA mutants arisen either in strain Cl3 or strain 401 are significantly different. The number of spontaneous amiA mutants, estimated by two methods, was found to be higher in strain 401 than in strain Cl3. The increase of the mutation rate in strain 401 could be accounted for by the excess of mutations falling in the two less-efficient classes observed in this strain. The discriminating process which acts during transformation presumably also intervenes in the appearance of spontaneous mutations.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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