Metaphase II: The two chromosomes in each daughter cell line up on the metaphase plate, in preparation for the final segregation event. Note that the mother cell prior to meioisis was heterozygous (genotype: A/a;B/b).

The two copies of the metacentric chromosome where gene A is located are not identical, because a crossing over event occurred during Prophase I. This chromosome is shown in one of the two cells. From the four choices shown at the left, choose the other chromosome that you expect to be found in the same cell and drag that to P1. If you choose correctly (there may be more than one correct choice), a congratulatory message will appear and the yellow box will become green. If you choose incorrectly, you will be asked to try to make another choice. Next, choose the chromosomes that you expect to be found in positions P2 and P3 (again there may be more than one correct choice). You may restart at any time by reloading the webpage.

Please try to explain why only some arrangements of chromosomes are possible due to the processes of crossing over and independent assortment that happen during meiosis.