plants tested (six), except Bt2 which showed a single-copy
insertion. Multiple-copy genotypes could result from insertions
at di!erent loci along the chromosomes or at the
same locus. The origin of multiplicity at a single locus
remains unknown, although copy organization is either
in tandem or as inverted repeats at a given locus (Delroles
and Gardner, 1988). The hybridization pattern in
the plants Bt5 and Bt6 was similar indicating that these
two plants probably arose from a single transformation
event. As expected, the non-transgenic tomato plant
DNA (Fig. 2, lane C) did not show any hybridization
signal.