Biology Honors: Genetics

In dogs, wire hair (S) is dominant to smooth (s). In a cross of a homozygous wire-haired dog with a smooth-haired dog, what will be the phenotype of the F1 generation?

In northeast Kansas there is a creature know as a wildcat. It comes in three colors, blue, red, and purple. This trait is controlled by a single locus gene with incomplete dominance. A homozygous (BB) individual is blue, a homozygous (bb) individual is red, and a heterozygous (Bb) individual is purple. What would be the genotype and phenotype of the offspring if a blue wildcat were crossed with a red one?

In humans the allele for albinism is recessive to the allele for normal skin pigmentation. If two heterozygous parents have children, what is the chance that a child will have normal skin pigment?

Knowing what you know about blood types... A man with AB blood marries a woman with type B blood. Please note, the woman’s mother had type O blood. What percentage of their children will have Type A blood?

In certain fish, red and blue fish when mated create offspring with a patchwork of blue AND red scales . What would be the genotypic and phenotypic probabilities for a cross between a blue fish and a fish with patchwork red/blue scales? What percentage of the fish will be red?

Knowing what you know about blood types... A mother had type A blood. Her husband has type B blood. They have a child with Type O blood. Is this possible?

In summer squash, white fruit color (W) is dominant over yellow fruit (w) and disk - shaped fruit (D) is dominant over sphere - shaped fruit (d). If a squash plant is true - breeding for white, disk - shaped fruit is crossed with a plant true - breeding for yellow, sphere - shaped fruit, what percentage of the offspring would be white and disk-shaped?

In fruit flies, the gene for white eyes is sex - linked recessive on the X chromosome. Red eyes are dominant. Cross a white - eyed female with a normal red - eyed male. What percent of offspring will be males with red eyes?

When a raccoon with wide tail stripes reproduces with a raccoon with narrow tail stripes, their offspring all have medium tail stripes. A medium tail striped raccoon mates with another ra ccoon with medium tail stripes. What percentage of the offspring will have narrow tail stripes?

In pea plants, spherical seeds (S) are dominant to dented seeds (s). In a genetic cross of two plants that are heterozygous for the seed shape trait, what fraction of the offspring should have spherical seeds?

After graduating from college, you decide to put your biology skills to work at a local company that does genetic counseling. Your first case is working with a couple that is trying to decide if it would be wise to conceive a child given the family’s genetic history with Huntington’s disease. This is a very damaging neurological disorder that usually strikes individuals later in life. The Huntington’s disease allele is a dominant allele (represented as “H”). Individuals who will not develop Huntington’s disease carry two copies of the recessive allele (represented as “h”). After testing both the wife and the husband, you determine that the wife’s genotype is hh and the husband’s genotype is Hh. Which of them will eventually develop Huntington’s disease?

Your second case at your new job is to counsel another couple who have a son with cystic fibrosis. Cystic fibrosis is a recessive disease that affects has a high incidence in the Caucasian population (1 in every 2500 births). Individuals with cystic fibrosis produce a thick mucus in the lungs and pancreas that can severely compromise breathing. The couple is unaffected (neither of them have cystic fibrosis themselves). “C” is used to represent the normal allele and “c” is used to represent the cystic fibrosis allele. (adapted from Genetics by P. Hedrick & R. Weaver) What are the genotypes for the couple?

Feeling the need for a change, you move to the company’s paternity testing department. In your first case, Mr. Chan’s former girlfriend claims that he is the father of her child. The child has O type blood. The child’s mother has B type blood. After testing a sample of Mr. Chan’s blood, you find that he has AB type blood. Could Mr. Chan possibly be the father of the child?

Pseudohypertropic muscular dystrophy is a disorder that causes gradual deterioration of the muscles. It is seen only in boys born to apparently normal parents and usually results in death in the early teens. Is its inheritance sex-linked or autosomal?

Red-green color blindness is caused by a sex-linked recessive allele. A color-blind man marries a woman with normal vision whose father was color-blind. What is the probability that they will have a color-blind daughter?

In rabbits, mono-colored fur (F) is dominant over spotted fur (f). Your son is entering the 4-H county fair for rabbits. He has a male white rabbit without spots and crosses it with a female white rabbit without spots. Some of the baby rabbitIn turkeys, bronze body color (B) is dominant over red (b). Normal feathers (N) are dominant over hairy feathers (n). A bronze male turkey is mated to a bronze female, and some of the poults (baby turkeys) produced by this cross are red. What are the genotypes of the male and female parentss have spots. What is the genotype of the male rabbit?

In turkeys, bronze body color (B) is dominant over red (b). Normal feathers (N) are dominant over hairy feathers (n). A bronze male turkey is mated to a bronze female, and some of the poults (baby turkeys) produced by this cross are red. What is the genotype of the female parent?

If you were to cross a Bbnn turkey with a bbNn turkey, what proportion of the offspring will have red, normal feathers?

A breeder of hamsters crosses a golden hamster with a black hamster. All the baby hamsters are golden. Which trait is dominant and which is recessive?

A court case has been filed by a mother with type O blood who has a son with type O blood. There are two fathers being accused; one has AB blood and the other A blood. Which one of the men could be the father of the child?