You want to map the positions of three genes (x, y, and z) all found on one chromosome in drosophila. each gene has one dominant allele and one recessive allele. you perform the three different two-factor crosses (cross 1: xy and xy, cross 2: yz and yz, and cross 3: xz and xz). assume all crosses are between diploid flies homozygous for the alleles of these genes. you observe 7% recombinants in the first cross, 20% recombi- nants in the second cross, and 13% recombinants in the third cross. draw a map placing the genes in the proper order and give the distance between each gene in map units (m.