Entire Linkage Research Articles

Linkage of fusidic acid resistance to the penicillinase plasmid in Staphylococcus aureus.

SUMMARY: In four out of five strains of Staphylococcus aureus examined, genes determining fusidic acid resistance were associated with a penicillinase plasmid. In one strain (FAR5), although the linkage was unstable, resistance to fusidic acid was co-transduced with resistance to cadmium ions and penicillinase production. Further evidence for a single plasmid in this strain was obtained by studying the physical nature of the plasmid DNA. The molecular weight of the entire linkage group was about 16 million daltons; the molecular weight of the residual plasmid after loss of fusidic acid resistance was about 15 million.

Parasexual cycle in cultivated human somatic cells.

Somatic segregation for three different autosomes was demonstrated in two strains of human diploid fibroblasts derived from subjects known to be heterozygous for chromosomal variants. Recombinant diploid cells appeared within cultures of tetraploid clones isolted from mass cultures. Tetraploid cells regularly occur in mass cultures and within clones of diploid cells. Such a parasexual cycle (2n-->4n-->2n), with recombination of entire linkage groups, could from the basis of a beginning formal genetic analysis in man.