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Independently Inherited Genes

In the cross AaBbCcDd x aaBbccDd, each of the 4 genes is inherited independently from the other 3 genes (the genes are all unlinked), and each of the four genes exhibits complete dominance.

a.What is the probability that an individual offspring will be phenotypically identical to the first parent?
b.What is the probability that two offspring from this cross will be heterozygous at all 4 genes?
c.What is the probability that an individual offspring's phenotype will be ABCD? What is the probability that an individuals offspring's phenotype will be abcd? What is the probability that an individual offspring's phenotype will be either ABCD or abcd?

Solution Preview

First let's look at the gametes produced by each parent.

AaBbCcDd produces gametes:
ABCD
ABCd
ABcD
ABcd
AbCD
AbCd
AbcD
Abcd
aBCD
aBCd
aBcD
aBcd
abCD
abCd
abcD
abcd

There is a 1/16 chance of getting any of these gametes.

aaBbccDd produces gametes:
4x aBcD
4x aBcd
4x abcD
4x abcd

There is a 4/16= 1/4 change of getting any of these gametes.

Now to the questions...
(a) The first parent has the genotype AaBbCcDd that is equal to a phenotype of ABCD (these are dominant alleles so ...

Solution Summary

Explanations and calculation of inheritance pattern of 4 genes.

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