Figure 1.

PCR colony screening of kan^R recombinant clones. (a) The upper band, 1.7 Kb in length (lanes 3, 6, 8, etc.), corresponds to the larger PCR product after insertion of recombination cassette into β-globin gene. 11 clones reveal lower wild-type band, 440 bp in length (lanes 5, 9, 10, etc.) as a result of recombination into other duplicated regions of the globin locus (γ^g and φβ). No PCR product (11 clones) is due to the δ-β deletion of the F primer binding site. Lanes 32,38 with double bands represent the colonies with heterogeneous BAC population within single colony. (b) Diagram of globin locus illustrating insertion of kan^R cassette at four different globin genes.