Exam 4: Sex Determination and Sex-Linked Characteristics

Explain the differences between incomplete dominance and continuous variation.

A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W, shown below. Assume A and B are dominant alleles.If this individual were crossed to an individual of genotype Aa Bb, what is the probability of a female offspring with the two dominant traits given by alleles A and B?

In domestic chickens, some males display a plumage pattern called cock feathering.Other males and all females display a pattern called hen feathering.Cock feathering is an autosomal recessive trait that is exhibited in males only.Two heterozygous birds are mated.What fraction of the total offspring is expected to exhibit cock feathering?

A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W, shown below. What is the probability of a gamete from this individual that has the following genotype: alleles A and b, chromosome Z?

You are studying body color in an African spider and have found that it is controlled by a single gene with four alleles: B (brown), b^r (red), b^g (green), and b^y (yellow).B is dominant to all the other alleles, and b^y is recessive to all the other alleles.The b^g allele is dominant to b^y but recessive to b^r.You cross a pure-breeding brown spider with a pure-breeding green spider.Predict the phenotype of the progeny.

In the yawncat (a rare hypothetical animal), the dominant allele R causes solid tail color, and the recessive allele r results in white spots on a colored background.The black coat color allele B is dominant to the brown allele b, but these genes can only be expressed if the animal has an mm genotype at a third gene locus.Animals that are M_ are yellow regardless of which allele from the B locus is present.A mating between a solid yellow-tailed male yawncat and a solid brown-tailed female yawncat produces 16 offspring with the following tail phenotypes: six solid yellow, two spotted yellow, three solid black, one spotted black, three solid brown, and one spotted brown.What is the MOST likely genotype of the male parent?

In domestic chickens, some males display a plumage pattern called cock feathering.Other males and all females display a pattern called hen feathering.Cock feathering is an autosomal recessive trait that is exhibited in males only.Two birds heterozygous for cock feathering are mated.What are the phenotypes of the parents?

Crossing two yellow mice results in 2/3 yellow offspring and 1/3 nonyellow offspring.What percentage of offspring would you expect to be nonyellow if you crossed two nonyellow mice?

Suppose that extra fingers and toes are caused by a recessive trait, but it appears in only 60% of homozygous recessive individuals.Two heterozygotes conceive a child.What is the probability that this child will have extra fingers and toes?

In a certain species of plant, flowers occur in three colors: blue, pink, and white.A pure-breeding pink plant is mated with a pure-breeding white plant.All of the F₁ are blue.When the blue F₁ plants are selfed, the F₂ occur in the ratio 9 blue:3 pink:4 white.The genotype that produces white is ww.The presence of one W allele allows pink or blue color to occur.The alleles at the hypostatic locus are B (blue)and b (pink).What is the genotype of the F₁ plants?

Cloning is a procedure by which exact genetic duplicates are made.Using cloning techniques, you produced 10 cloned cows.However, the fur color of each of the calves looks very different from one another.Explain why this might have occurred.

Which of the following is a characteristic exhibited by cytoplasmically inherited traits?

A mother with blood type AB has a child with blood type B.Give all possible blood types for the father of this child.

In a certain species of plant, flowers occur in three colors: blue, pink, and white.A pure-breeding pink plant is mated with a pure-breeding white plant.All of the F₁ are blue.When the blue F₁ plants are selfed, the F₂ occur in the ratio 9 blue:3 pink:4 white.What is the name for this type of interaction?

The bicoid mutation (bcd^-)in fruit flies is inherited as a maternal effect recessive allele.What is the expected ratio of phenotypes in the offspring of a cross between a bcd⁺/bcd^- female and a bcd⁺/bcd^- male?

What is the sex chromosome constitution of a male duck-billed platypus?

A mother with blood type B has a child with blood type O.Give all possible blood types for the father of this child.

In some plant species, a single pair of alleles is involved in both flower color and stem color.For example, a plant with red flowers may also have red stems, whereas white-flowered varieties of the same species have green stems.How would you explain this observation?

Hair color is determined in Labrador retrievers by alleles at the B and E loci.A dominant allele B encodes black pigment, whereas a recessive allele b encodes brown pigment.Alleles at a second locus affect the deposition of the pigment in the shaft of the hair; dominant allele E allows dark pigment (black or brown)to be deposited, whereas recessive allele e prevents the deposition of dark pigment, causing the hair to be yellow.A black female Labrador retriever was mated with a yellow male.Half of the puppies were black and half were yellow.If the genotype of the black female parent was Bb Ee, then what was the genotype of the other parent?

A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W, shown below. From what type of individual is this cell?