In the following schematic drawing of a Holliday junction, one chromatid is shown in red, and the homologous chromatid is shown in blue. The red chromatid carries a dominant allele labeled A and a recessive allele labeled b, whereas the blue chromatid carries a recessive allele labeled a and a dominant allele labeled B.

Where would the DNA strands have to be cut to produce recombinant chromosomes? Would they be cut at sites 1 and 3, or at sites 2 and 4?
What would be the genotypes of the two recombinant chromosomes?

B 2 3 a