# Genetics Question

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#### 90210

##### Full Member
10+ Year Member
Can anyone help me figure this question out?

Parent 1 is: AaBbCcDD
Parent 2 is: AABbCCDD

What is the probability of producing a child with the genotype: AAbbCCDD

I made this question up. But because I see it a lot in practice, I was curious if someone could help me figure out how to approach these types of problems. Thank you.

Can anyone help me figure this question out?

Parent 1 is: AaBbCcDD
Parent 2 is: AABbCCDD

What is the probability of producing a child with the genotype: AAbbCCDD

I made this question up. But because I see it a lot in practice, I was curious if someone could help me figure out how to approach these types of problems. Thank you.

Am sure there are many ways of doing this type and am actually interested in so other peoples opinions on this.

The way I would do it is to treat each allele separately. First the D's. What is the probability based on the parents that you get a DD homozygous? Its 100% since that is the only allele. Next the C's, the probability of getting CC with the cross Cc and CC is 1/2 or 50% and that is just based on a regular punnett square. Keep doing this for the other ones and youll see that getting bb from the cross of Bb and Bb is 1/2 and getting AA from the cross of Aa and AA is also 1/2. The probability of all these events happening at the same time is the product of the probability of each one. So 1/2 *1/2 *1/2 = 1/8

Am sure there are many ways of doing this type and am actually interested in so other peoples opinions on this.

The way I would do it is to treat each allele separately. First the D's. What is the probability based on the parents that you get a DD homozygous? Its 100% since that is the only allele. Next the C's, the probability of getting CC with the cross Cc and CC is 1/2 or 50% and that is just based on a regular punnett square. Keep doing this for the other ones and youll see that getting bb from the cross of Bb and Bb is 1/2 and getting AA from the cross of Aa and AA is also 1/2. The probability of all these events happening at the same time is the product of the probability of each one. So 1/2 *1/2 *1/2 = 1/8

Alright, thank you very much for that explanation. Makes perfect sense. I recall a shortcut though from Kaplan (during a practice quiz I took online). I wish I could remember it. If anyone knows, please post it Thanks.

youll see that getting bb from the cross of Bb and Bb is 1/2

You may want to check your math on that one!

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You may want to check your math on that one!

Sigh.... thats exactly the type of stupid mistakes I keep consistently making.