Mitchell is interested in the snapdragons that reproduce sexually. He knows that purple (P) is dominant to white (w). Mitchell crosses a homozygous purple plant with a homozygous white plant. If he breeds two of the first generation offspring together, what percentage of the second generation offspring can Mitchell predict will most likely be white?

1 answer

If Mitchell crosses a homozygous purple plant (PP) with a homozygous white plant (ww), the first generation offspring will all be heterozygous purple (Pw). This is because purple (P) is dominant to white (w), so even if only one of the alleles is purple, the plant will appear purple.

When the first generation offspring (Pw) are bred together, they will have the following combinations of alleles: PP, Pw, Pw, and ww. There are four possible combinations, and only one of them (ww) will result in a white plant.

Therefore, Mitchell can predict that 25% (1 out of 4) of the second generation offspring will most likely be white.