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. 1975 Aug;80(4):667–678. doi: 10.1093/genetics/80.4.667

Chromosomal Basis of the Merozygosity in a Partially Diploid Mutant of Pneumococcus

Mary Lee S Ledbetter 1, Rollin D Hotchkiss 1
PMCID: PMC1213367  PMID: 270

Abstract

A sulfonamide-resistant mutant of pneumococcus, sul r-c, displays a genetic instability, regularly segregating to wild type. DNA extracts of derivatives of the strain possess transforming activities for both the mutant and wild-type alleles, establishing that the strain is a partial diploid. The linkage of sulr-c to str r-61, a stable chromosomal marker, was established, thus defining a chromosomal locus for sulr-c. DNA isolated from sulr-c cells transforms two mutant recipient strains at the same low efficiency as it does a wild-type recipient, although the mutant property of these strains makes them capable of integrating classical "low-efficiency" donor markers equally as efficiently as "high efficiency" markers. Hence sulr-c must have a different basis for its low efficiency than do classical low efficiency point mutations. We suggest that the DNA in the region of the sulr-c mutation has a structural abnormality which leads both to its frequent segregation during growth and its difficulty in efficiently mediating genetic transformation.

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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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