Exam 2: Mendels Principles of Heredity

In a dihybrid cross AA bb × aa BB, what proportion of the F₂ offspring is expected to be homozygous for at least one gene?

Assume that in guinea pigs, dark brown fur (B)is dominant to black fur (b).If you mate a black guinea pig with a homozygous brown guinea pig, what proportion of the progeny will be homozygous?

Below is a pedigree of a human genetic disease in which solid color indicates affected individuals.Assume that the disease is caused by a gene that can have the alleles A or a. -What is/are the possible genotype(s)of person 1?

An Ss × Ss mating is performed.If the phenotypic ratio of the progeny is 3 S- (- indicates that the other allele is unknown)to 1 ss, then

Suppose that in plants, smooth seeds (S)is dominant to wrinkled seeds (s), and tall plants (T)is dominant to short plants (t).An F₁ plant from a mating between homozygous plants that were tall/smooth and short/wrinkled was crossed to the short/wrinkled parent.What proportion of the progeny is homozygous for short and wrinkled alleles?

An allele of the pea color gene specifies the enzyme Sgr, which normally functions in a pathway to break down chlorophyll during pea maturation, resulting in yellow mature peas.A second allele of the Sgr gene produces no enzyme and is the ________ allele.

For each of the following pedigree symbols, select the correct meaning. -

According to Mendel's law of equal segregation, an Aa monohybrid makes two types of gametes with equal frequency.These two gamete types are:

In a monohybrid cross AA × aa, what proportion of homozygotes is expected among the F₂ offspring?

In the testcross Aa Bb × aa bb, what proportion of individuals are expected to be homozygous for both genes in the F₁ generation?

A phenotype reflecting a new combination of genes occurring during gamete formation is called

Below is a pedigree of a human genetic disease in which solid color indicates affected individuals.Assume that the disease is caused by a gene that can have the alleles A or a. -What is/are the possible genotype(s)of person 3?

In corn, having ligules (L) is dominant to liguleless (l), and green leaves (G) is dominant to white leaves (g). -If a pure-breeding plant that is liguleless and has green leaves is crossed to a pure-breeding plant with white leaves and ligules, predict the genotypes and phenotypes of the F₁.

What is the outcome of crossing two pure-breeding plants with antagonistic traits?

The reason that the HD allele acts as a dominant allele is that

What is the difference between cross- and self-fertilization?

Suppose that in plants, smooth seeds (S)is dominant to wrinkled seeds (s)and tall plants (T)is dominant to short plants (t).An F₁ tall plant with smooth seeds was crossed to a parent plant that was short and wrinkled.What proportion of the progeny is expected to be heterozygous for tall and smooth?

Mendel's law of independent assortment dictates than an Aa Bb dihybrid would make equal numbers of four gamete types.What are these four gamete types?

The alleles present in an individual make up the individual's

In some genetically engineered corn plants, a Bt gene was added to a chromosome.The Bt gene specifies a protein called Bt that is lethal to certain flying insect pests that eat the corn plants.If the corn plant is is heterozygous for the Bt gene (one homolog has the introduced Bt gene and the other does not), what proportion of the sperm would carry the Bt gene? Is the presence of the Bt gene (a mutation)dominant or recessive to its absence (the wild type)?