Exam 14: Patterns of Inheritance

The agouti gene,when expressed in mice,makes them obese,ravenous,yellow,and prone to diabetes.The agouti phenotype is dominant.During ovulation an agouti mouse is given a drug that methylates (or shuts off the agouti gene).She is then bred to another mouse and gives birth to a litter of baby mice,none of whom have the agouti phenotype.Which of the following is accurate?

A man has a mutation in a mitochondrial gene encoding a subunit of the ATP synthase complex.The mutation leads to a defective ATP synthase that is not able to synthesize ATP effectively,and this in turn leads to extreme muscle weakness in the affected individual.If this man has children,what is the likelihood that they will inherit this disease from him?

In wolves,gray coat color (G)is dominant to black (g)and brown eyes (B)are dominant to blue (b).The genes that control these traits are located on different chromosomes.The alpha male of the pack has the dominant phenotype for both traits and is heterozygous for both traits.The alpha female has brown eyes and a black coat;she is heterozygous for eye color.The alpha male and the alpha female mate.What proportion of their offspring will have the same phenotype as the mother?

Pea plants cannot self-fertilize because an individual plant is either female or male,having either ovaries or stamens but not both.

In cats,a fur color gene is on the X chromosome.At this locus,cats can have a black allele or an orange allele.Cats who are homozygous for the black allele have black fur,cats who are homozygous for the orange allele have orange fur,and cats who are heterozygous at this locus are tortoiseshell.What offspring would you expect from a cross between an orange female and a black male?

The inheritance pattern in which the mother provides gene products to the developing egg cells is called

Which of the following is evidence supporting the Lyon hypothesis of X inactivation?

Barr bodies

A mitochondrion has its own genome,so it can live independently from a eukaryotic cell.

Paternal inheritance occurs in plants but not animals because plants have chloroplasts instead of mitochondria.

The color of petunia flower can be changed from red to blue by altering the pH of the soil.This is an example of

Anury is the absence or abbreviation of the tail in sheep (and also other animals).It is inherited in an autosomal dominant fashion.A ram with anury is mated to a ewe with a normal tail.The ram's father had anury,his mother did not.What is the probability that the ram and ewe will produce a lamb with anury? (ram = male;ewe = female)

Incomplete dominance is when

Nearsightedness is dominant to normal vision and hazel eyes are dominant to blue eyes.A nearsighted woman with hazel eyes who is heterozygous for both traits marries a man with normal vision and hazel eyes.His genotype for eye color is the same as his wife's.Their three children all have blue eyes and normal vision.What is the probability that their next child will have blue eyes and be nearsighted?

Hemophilia A is an X-linked recessive genetic condition.In humans it is due to a mutation in the F8 gene,which encodes a protein called coagulation factor VII.Coagulation factors are proteins important in blood clotting.Individuals with hemophilia,when injured,bleed longer than a normal,healthy individual;the inability to normally clot blood can be life threatening.Which of the following statements is NOT a reason why hemophilia is much more common in males than in females?

Type 1 fucosidosis is a rare human disease.Patients cannot hydrolyze the disaccharide fucose,and as a result have severe neurological decline and die by age 6.The disease is due to a defect in the gene that encodes the lysosomal enzyme that breaks down fucose ( $\alpha$ -1-fucosidase),and is inherited in an autosomal recessive manner.Which of the following statements is ACCURATE about Type1 fucosidosis?

The law of independent assortment states that the two alleles of the same gene will segregate from each other during gamete formation.

A homologous pair of chromosomes at the beginning of mitosis will possess _______ alleles for each locus.

What features of meiosis allow for independent assortment of chromosomes?

Polydactyly is a dominant trait that results in extra fingers and toes in humans.A man with polydactyly marries a woman with 10 fingers and toes.They have a child that has a normal number of digits.The phenotype of the man's father is unknown,but his mother has a normal phenotype.What are the genotypes of the married couple? (D = polydactyl allele;d = wild type allele)