Genetics Quiz 2

The ASIP gene (or “agouti” gene) controls the distribution of melanin in a mammal’s hair or fur.  In leopards, there are two alleles for the gene and the gene shows dominant-recessive inheritance.  The DOMINANT allele (A) causes leopards to have spots.  The recessive allele (a) causes a leopard’s fur to be completely black.  Leopards with the recessive phenotype are called black panthers.

Why is a heterozygous leopard (Aa) able to have a black panther cub, but a homozygous dominant leopard (AA) cannot?

• The heterozygous leopard can pass a DOMINANT allele to the offspring.

• Heterozygous leopards (Aa) cannot have black panther cubs.

• Homozygous dominant leopards (AA) do not mate with black panthers.

• The heterozygous leopard can pass a recessive allele to the offspring.

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The ASIP gene (or “agouti” gene) controls the distribution of melanin in a mammal’s hair or fur.  In leopards, there are two alleles for the gene and the gene shows dominant-recessive inheritance.  The DOMINANT allele (A) causes leopards to have spots.  The recessive allele (a) causes a leopard’s fur to be completely black.  Leopards with the recessive phenotype are called black panthers.

What is the probability that a heterozygous leopard (Aa) and a black panther (aa) will have a black panther cub?

• 25%
• 50%
• 100%
• 75%

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How does this Punnett square show the Principle of Segregation?

• Each parent is only passing down one allele for the gene.

• The offspring have two alleles for the gene.

• Some offspring have the same phenotype as one of the parents.

• Some alleles are dominant, while others are recessive.

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The MC1R gene controls the color of melanin that the body produces. The gene shows dominant-recessive inheritance and typically has two alleles. The DOMINANT allele (E) produces animals with DARK FUR. The recessive allele (e) produces animals with red fur. A heterozygous dog (Ee) has eight black puppies. This means that the other parent was most likely... (a)  

• homozygous DOMINANT (EE)
• heterozygous (Ee)
• homozygous recessive (ee)

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The MC1R gene controls the color of melanin produced by the body. The DOMINANT allele (E) produces dark hair. The recessive allele (e) produces red hair. Another gene, the TCHH gene, controls hair texture. The DOMINANT allele (H) produces curly or wavy hair. The recessive allele (h) produces straight hair.

A mother has wavy, red hair (ee, Hh). If her child inherits the recessive hair color allele (e), does that guarantee that they will also inherit the recessive hair texture (h)?

• No, alleles are inherited independently from each other.

• Yes, you either inherit all of a parent's DOMINANT alleles or all of their recessive alleles.

• No, if you inherit one recessive allele you will always inherit a DOMINANT allele to balance it out.

• Yes, a person either only has DOMINANT alleles or recessive alleles.

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The MC1R gene controls the color of melanin produced by the body. The DOMINANT allele (E) produces dark fur. The recessive allele (e) produces red fur. Another gene, the PKD1 gene, can cause kidney disease. The DOMINANT allele (K) causes polycystic kidney disease. The recessive allele (k) produces normal kidneys.

Two heterozygous mice with DARK FUR and KIDNEY DISEASE (Ee, Kk) have a baby with DARK FUR and no kidney disease (Ee, kk). How does this show the Principle of Independent Assortment?

• The parents passed down one allele per gene.

• Inheriting dark fur did not affect inheriting kidney disease.

• The baby inherited DOMINANT alleles and recessive alleles.

• The baby's MC1R gene made RNA, which made the MC1R protein.

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