Question 28 A person who has PKU, a recessive genetic disorder,
А
inherited the allele for the trait from one parent.
B
inherited the allele for the trait from both parents.
С
is heterozygous for the trait.
ОО
D
will not pass the allele for the trait to his or her offspring.

B

Explanation:

In order for one to have a recessive trait, both parents must carry the trait.

XX Xy= XX XX Xy Xy

Xy Xy= XX Xy Xy YY

XX XX= XX XX XX XX

yy yy= yy yy yy yy

Only the options in which both parents have the allele can pass it on. Only if there is no dominant allele will the trait be expressed, which can only be a yy recessive (since heterozygous would be dominant). Therefore, he will pass the allele on to his/her offspring.

small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.

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