Chromosome transfer and recombinant formation with deoxyribonucleic acid temperature-sensitive strains of Escherichia coli.

Haploid recombinant yield is reduced in matings conducted at 42.5 C between deoxyribonucleic acid (DNA) temperature-sensitive [dna(-)(TS)] recipients unable to synthesize DNA at 42.5 C and any of the three major donor types (Hfr, F(+), F') of Escherichia coli. No such reduction is observed in matings conducted at 42.5 C when the dna(-)(TS) mutation is in the donor parent. Evidence is presented which indicates that chromosome transfer from donors to recipients unable to replicate DNA at 42.5 C during vegetative growth occurs at normal frequencies when the mating is conducted at 42.5 C. It is concluded that some stage in haploid recombinant formation is adversely affected in dna(-)(TS) recipients mated at the temperature restrictive for DNA synthesis.