Genetics Quiz

In a certain species of insect, eye color is controlled by a single gene. The dominant allele (E) codes for black eyes, while the recessive allele (e) codes for red eyes. How could two parents with black eyes have a red-eyed female offspring?

• The parents are heterozygous for eye color, so their offspring must inherit the recessive allele from both parents.

• The parents are homozygous recessive for eye color, so all of their offspring will inherit red eyes.

• Since the offspring is female, it did not inherit any Y chromosomes with the gene for black eyes, and thus has red eyes.

• Since the offspring is heterozygous for eye color, environmental factors are causing it to produce more red pigment than black, and thus has red eyes.

In human genetics, the allele for having freckles is inherited apart from the allele for having attached earlobes. Which one of Mendel's principles does this illustrate?

• principle of alleles

• principle of dominance

• principle of independent assortment

• principle of segregation

The phenotype of an animal depends MOST directly on

• The metabolic rate of the animal

• How the genes of an animal are expressed

• The source of the animal's food

• The number of cells in the animal's body

The white-tailed deer, Odocoileus virginianus, is common in the Eastern United States. Most deer have reddish brown fur, but occasionally a deer may be born with a genetic condition known as albinism which results in white fur. Albinism is caused by the inheritance of two recessive alleles for the production of coloration pigments. If an albino deer is born to two parents who each have normal fur coloration, what conclusion may be drawn about the genotypes of the parent deer?

• No conclusion may be drawn about the parental genotypes based on the information given.

• Both parents must be homozygous for the coloration gene.

• Both parents must be heterozygous for the coloration gene.

• The female parent must have two recessive alleles for the coloration gene.

In a given hybridization between two flowers, red "R" is dominant, and white "r" is recessive. In a cross between two white-flowered plants, all of the offspring had white flowers. If a plant grower wanted to produce red flowers, what should they consider during breeding?

• The breeder must introduce a plant that is homozygous dominant for white flowers.

• The breeder cannot manipulate the flower color. It would be best to begin with a different set of parent plants.

• Flower color variation would depend on mutations in this case. There is no other way to change flower color of this population of plants.

• The breeder must introduce at least one parent that is heterozygous for red flowers.

In the dihybrid cross, which of the following best represents the box labeled O.

• TtYy

• ttYY

• TTYy

• ttYy

The Punnett square shown presents a cross between two piranha. Both parents have large teeth. According to the chart, which combination describes the offspring expected from the cross?

• 50% large-toothed and 50% small-toothed

• 75% small-toothed and 25% large-toothed

• 75% large-toothed and 25% small-toothed

• 100% large-toothed

In the dihybrid cross above, which of the following best represents the box labeled O.

• TtYy

• ttYY

• TTYy

• ttYy

The phenotype of an animal depends MOST directly on

• The metabolic rate of the animal

• How the genes of an animal are expressed

• The source of the animal's food

• How many cells are in the animal's body

Which of the following is expressed only when homozygous?

• Dominant traits

• Recessive traits

• Both dominant and recessive traits