Examination of mode of homologous integration in transformants of T. aureum ATCC 34304 by PCR. (A) Genomic PCR for detection of single-crossover homologous recombination in TSCNeor transfectants. Primer sets used and sizes of amplicons are as follows: primers Ta18S F1 and Svec det R (2.0 kbp) and primers Sneo F and Ta18S R (2.4 kbp). Lanes: M1, bacteriophage λ HindIII digest (marker); M2, phage ϕX174 HincII digest (marker); S, TSCNeor transfectants (each number corresponds to the transformant's number); N, negative control (pTSCNeor was used as the PCR template); W, negative control (wild type). (B) Genomic PCR for detection of a double-crossover homologous recombination in TDCNeor transfectants. Primer sets used and sizes of amplicons are as follows: primers Ta18S F2 and Sneo R (2.0 kbp) and primers Sneo F and Ta18S R (2.4 kbp). Lanes: M1, bacteriophage λ HindIII digest (marker); M2, phage ϕX174 HincII digest (marker); D, TDCNeor transfectants (each number corresponds to the transformant's number); N, negative control (pTDCNeor was used as the PCR template); W, negative control (wild type). Details are described in Materials and Methods.