A group of students wanted to determine how the ability to taste PTC, a nontoxic chemical, is passed from one generation to the next. The students decided to test families in their community for this ability. The students gave each family member a paper strip coated with a small amount of PTC. Those who experienced the bitter taste of PTC when they touched the paper strips to their tongues were called "tasters"; those who could not taste the PTC were called "nontasters."

The results of the experiment are shown in the table below.

Based on the data the students collected, the allele for tasting PTC is most likely

In humans, the allele for dimples (D) is dominant. The allele for not having dimples (d) is recessive. A woman (DD) and a man (Dd) have four children. Which of these is the predicted ratio of the children with dimples to the children without dimples?

In humans, the allele for unattached earlobes (E) is dominant. The allele for attached earlobes (e) is recessive. A woman who is heterozygous for this trait marries a man who has attached earlobes. What is the probability that this couple's child will have unattached earlobes?

The presence or absence of freckles is determined by one gene. The allele for freckles (F) is dominant and the allele for the absence of freckles (f) is recessive.

A couple has several children. All of the children have freckles because their parents' genotypes can only produce children with freckles.

Which of these are most likely the genotypes of the two parents?

In horses, the allele for straight hair (B) is dominant to the allele for curly hair (b). Which of these sets of parents can produce offspring with curly hair?

Use the information and the table below to answer the following.

A group of students wanted to determine how the ability to taste PTC, a nontoxic chemical, is passed from one generation to the next. The students decided to test families in their community for this ability. The students gave each family member a paper strip coated with a small amount of PTC. Those who experienced the bitter taste of PTC when they touched the paper strips to their tongues were called "tasters"; those who could not taste the PTC were called "nontasters."

The results of the experiment are shown in the table below.

Which of these explains how two taster parents could produce a nontaster child?

Which of these combinations results in the expression of a recessive trait?

Galactosemia is an inherited disorder in humans. A person with the disorder cannot digest the sugars in milk. The allele for normal digestion (G) is dominant; the allele for galactosemia (g) is recessive.

A female who is heterozygous for the galactosemia trait and a male who has galactosemia have a child.

Describe how this disorder could have been passed on in the family. In your response, be sure to

• identify the genotype of the father
• complete a Punnett square to show the possible genotypes and phenotypes of the child
• describe the probability that the child will inherit galactosemia
• describe all the possible genotypes and phenotypes of the father's parents; explain your answer

Write your answer in your Answer Book.

The length of a dog's tail is an inherited trait. The allele for short tails is dominant (T) over the allele for long tails (t). A dog breeder mates two short-tailed dogs (parents). One parent is homozygous and the other is heterozygous for this trait. A litter of twelve puppies, all with short tails, is produced (first generation). The breeder mates one of the first generation dogs with a short-tailed dog from another litter. A litter of ten puppies is produced (second generation). The breeder is surprised when one of the second generation puppies has a long tail.

Describe the genetic make-up of the parents and puppies that produced this inheritance pattern. In your response, be sure to

• identify the genotype of the parents
• use a Punnett square to show the possible genotypes of the first generation puppies
• use a Punnett square to show the possible genotypes of the second generation puppies
• identify the genotypic and phenotypic ratios of the first and second generation puppies
• explain how a long-tailed dog can suddenly appear when all the other dog's were short-tailed

Write your answer in your Answer Book.

In humans, the allele for long eyelashes is dominant (L) and the allele for short eyelashes is recessive (l). A female who is heterozygous for long eyelashes and a male with short eyelashes have a child.

What is the probability that their offspring will have short eyelashes?

In a species of fly, the allele for red eyes (R) is dominant to the allele for brown eyes (r). Red eye color in the flies is not sex-linked. Students crossed male and female flies that had red eyes and recorded the eye color of their offspring. Their data are shown below.

What are the most likely genotypes of the parent flies?

The allele for attached earlobes (e) is recessive to the allele for unattached earlobes (E). A woman with the genotype (Ee) and a man with the genotype (ee) have a child.

What is the probability that the child is heterozygous for attached earlobes?

Which of these is an example of a heterozygous genotype?

Use the information and Punnett square below to answer the following question.

In guinea pigs, the allele for black fur (B) is dominant. The allele for brown fur (b) is recessive. Two guinea pigs were crossed as shown in the Punnett square below. Numbers 1, 2, 3, and 4 represent the types of offspring produced from the cross.

What is the probability that an offspring from this cross would have brown fur?

Use the information and Punnett square below to answer the following question.

In guinea pigs, the allele for black fur (B) is dominant. The allele for brown fur (b) is recessive. Two guinea pigs were crossed as shown in the Punnett square below. Numbers 1, 2, 3, and 4 represent the types of offspring produced from the cross.

Which of these describes the phenotypes of the parent guinea pigs?

A scientist wants to determine the genotype of a black female rabbit. She knows that the allele for black fur (B) is dominant to the allele for brown fur (b) and is not sex-linked. The scientist performs a cross with a brown male rabbit to try to determine the genotype of the female rabbit.

Complete the following steps to determine if the black female rabbit is homozygous or heterozygous for fur color.

• Identify the two possible genotypes of the female rabbit.
• Complete two Punnett squares using the possible genotypes of the parent rabbits to show the expected offspring.
• Explain how the fur color of the offspring would help the scientist determine the genotype of the female rabbit.

Write your answer in your Answer Book.

One parent is homozygous dominant for brown hair (BB). The other parent is heterozygous for brown hair (Bb).

What is the probability that the offspring will have brown hair?

Use the information and the pedigree below to answer Numbers 24 through 26.

Use the information and the pedigree below to answer the following item.

In humans, the allele for having feet with normal arches is dominant (A). The allele for flat feet is recessive (a). The pedigree below shows the occurrence of normal arches and flat feet in four generations of a family. In the pedigree, individuals are identified by the generation and individual numbers. For example, Individual 2 in Generation I is identified as I-2.

Which of these individuals in the pedigree is a male with the genotype aa?

Use the information and the pedigree below to answer the following item.

In humans, the allele for having feet with normal arches is dominant (A). The allele for flat feet is recessive (a). The pedigree below shows the occurrence of normal arches and flat feet in four generations of a family. In the pedigree, individuals are identified by the generation and individual numbers. For example, Individual 2 in Generation I is identified as I-2.

Individuals III-6 and III-7 have two children and are expecting a third child. Their two children have flat feet. What is the chance that the third child will have normal arches?

Use the information and the pedigree below to answer the following item.

In humans, the allele for having feet with normal arches is dominant (A). The allele for flat feet is recessive (a). The pedigree below shows the occurrence of normal arches and flat feet in four generations of a family. In the pedigree, individuals are identified by the generation and individual numbers. For example, Individual 2 in Generation I is identified as I-2.

Which of these Punnett squares shows the cross between Individual II-4 and Individual II-5?

Red-green color blindness affects about 7.0% of the human male population. It affects approximately 0.4% of the human female population. These data suggest that red-green color blindness is a

In humans the trait of having freckles (F) is dominant to not having freckles (f).

Which genotype and phenotype are correctly paired?