please answer this with explaination Figure 420 A Drosophila

please answer this with explaination

Figure 4.20 A Drosophila e color gene is located on the chromosome. x-linkage explains the inheritance of alleles of the white gene in this series of crosses performed by Thomas Hunt Morgan.The progeny of crosses A, B, and Coutlined with green dotted boxes are those used as the parents in the next cross of the series. Cross A Cross B IXWY X X X X All progeny red-eyed 3 red 1 white Cross D Cross C X X Crisscross inheritance

Solution

In the given case the data will not match with the data in the figure 4.20. If Y chromosome had additional copy of eye color gene then a femal in the absence of eye color and rececive at both the loci should be crossed with the male with eye color, then the possibility that the Y chromosome carries a copy of the eye color gene could be rulled out.