Chromosomal basis of the merozygosity in a partially deploid mutant of Pneumococcus.
A sulfonamide-resistant mutant of pneumococcus, sulr-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 strr-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.
D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003433:Crosses, Genetic; D004261:DNA Replication; D004171:Diploidy; D004352:Drug Resistance, Microbial; D008040:Genetic Linkage; D006238:Haploidy; D009154:Mutation; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D013449:Sulfonamides / Q000494:pharmacology; D014170:Transformation, Genetic
D013449:Sulfonamides