Lecture 3 exam 2

UIC BioS 101 Nyberg

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More ABO genetics

• A student has type A blood. Both her parents have type A blood. What observation would tell you that BOTH of her parents were heterozygous, IAi ?

• ANSWER If any of the student’s siblings had type O blood.

Speaker Notes:

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If either parent were homozygous, ALL the offspring would have the A phenotype.

If three children exist an all have type A blood, it is still quite possible that both parents are heterozygous.