Homework Answers

If an allele is visibly expressed only in homozygous individuals (not heterozygous individuals), that allele would be considered
recessive

When an individual is ______ for a particular trait, they have two copies of the same allele for that trait.
homozygous

Individuals rarely inherit the gene for blue eyes and black hair. Instead, they are much more likely to inherit the gene for brown eyes if they inherit the gene for black hair.
Considering this, how would you describe the hair color gene?
It is a linked gene

In the pedigree above, males are more likely to be affected by this disorder while females are more likely to be a carrier. This means it is likely _____. Because females can be a carrier for this disorder, it would be considered a ______ disorder. X-linked, recessive

Identify which term is being described by each statement below.
Not all terms will be used! These traits have a wide range of possible phenotypes.
Quantitative traits
This occurs when heterozygous individuals express a phenotype between the dominant & recessive phenotypes.
Incomplete dominance

The _____ of the puppy above is homozygous dominant (for the fur color gene).
The ______ of the puppy is yellow fur.
genotype, phenotype

What is true about autosomal recessive disorders?
They affect men & women roughly equally.

Consider the gene that regulates ability to roll your tongue into a tube.

• The dominant allele (R) enables you to roll your tongue.
• The recessive allele (r) does NOT allow you from rolling your tongue.

A person with the genotype RR ______ be able to roll their tongue.
A person with the genotype Rr ______ be able to roll their tongue.
A person with the genotype rr ______ be able to roll their tongue.
would, would, would not

In the pedigree above, both males & females are affected (roughly equally). This means this disorder is likely ______
The affected individuals in this pedigree do NOT have affected parents. This means this disorder is likely _______
autosomal, recessive

Suppose a woman is a carrier for an X-linked recessive disorder.
What would be true about her children?
50% of her sons would have the disorder & 50% of her daughters would be carriers.