Genomic Southern blot showing new copies of tagged Zorro3 elements in URA3+ derivatives. The blot was probed with the C. albicans URA3 gene. Each lane contains DNA cut with Hin dIII. Lane M contains the transforming vector. CAI4 is the ura3- host strain. The 'A' lanes contain DNA from two independent ura3- transformants. Lanes B-E contain DNA from four independent URA3+ derivatives. The additional bands in these lanes represent newly retrotransposed copies of the tagged Zorro3 element. Bands at 6.5 kb (the same size as that present in the marker lane) likely represent tandem integrations of the vector in the genome. The bands at 12.3 kb are of the size expected for the sequence at the border between the tandem copies of the vector and the genomic insertion site.