Female Drosophila with cinnabar eye (cn) and vestigial wings (vg) were mated to males
with roof wings (rf). The F1 were all wild-type. When the F1 females were test crossed with
males homozygous for all three traits the following result were obtained.
382 cinnabar, vestigial P
401 roof P
3 cinnabar DCO
4 roof, vestigial DCO
59 cinnabar, roof, vestigial SCO1
67 wild SCO1
44 cinnabar, roof SCO2
40 vestigial SCO2
i) To determine the gene order (rf is not given on the gene map) compare the parental and DCO
phenotypes.
The correct order of the loci is
ii) The genotype of F1 would have been


iii) The phenotypes “cinnabar-roof-vestigial” and “wild” were formed as a result of a single
crossover between
and
Calculated map distance.
iv) The phenotypes (“cinnabar-roof” and “vestigial” were formed as a result of a single crossover
between
and .
Calculated map distance
v) From the gene map (Appendix B) the locus of cn is and vg is
Map distance cn - vg is
vi) From these calculations what would be the locus for roof wings? Draw a gene map segment.