Exam 3: Basic Principles of Heredity

In animals, the inability to make the pigment melanin results in albinism, a recessive condition. Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa). What is the probability that the second and third children will also have albinism?

In peas, tall (T) is dominant to short (t). A homozygous tall plant is crossed with a short plant. The F₁ plants are self-fertilized to produce the F₂. Both tall and short plants appear in the F₂. If the tall F₂ plants are self-fertilized, what types of offspring and proportions will be produced?

A space capsule crashes to earth with an alien life form aboard. Two creatures emerge from the capsule, one with green skin and one with yellow skin. The yellow creature soon gives birth to offspring fathered by the green creature, producing 12 green and 8 yellow offspring. Green skin in these diploid creatures is dominant to yellow skin. You are curious to find out if the number of offspring is significantly different from expected Mendelian ratios, so you perform a chi-square test. What is the chi-square value for this cross?

In Mendel's peas, yellow seeds are dominant to green. A pure-breeding yellow plant is crossed with a pure-breeding green plant. All of the offspring are yellow. If one of these yellow offspring is crossed with a green plant, what will be the expected proportion of plants with green seeds in the next generation?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. -What is the probability of producing an AaBb zygote from a cross of AaBb × AABB?