Q10 correct + explanation!

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To explain this one, we need to first work out some possible genotypes –

Yellow – parents are A and O, therefore this person must be AO.

Green – parents are AB and AO (you know this because the blue O from the last question). However, because orange is OO, then green must be AO.

Purple is the offspring from AO x AO. Draw a quick Punnet square and you’d see 1/4 AA, 2/4 AO, 1/4 OO. But they aren’t OO, so its 1/3 AA and 2/3 AO

We know red’s parent is BO.

To work out red, we need to do two Punnett squares for the different potential genotypes of purple and then take the proportion of each relative to the probability (1/3 or 2/3).

If the mother is AA, then 50% AB, 50% AO

If the mother is AO, then 25% AB, 25% BO, 25% AO and 25% OO

To calculate absolute percentages.

  • AO = (1/3 x 1/2) for AA mother + (2/3 x 1/4) for AO mother = 33%
  • AB = (1/3 x 1/2) for AA mother + (2/3 x 1/4) for AO mother = 33%
  • BO = (2/3 x 1/4) for AO mother = 16.7%
  • OO = (2/3 x 1/4) for AO mother = 16.7%