Name ______

Probability WS

  • For questions 1-7, show all work on a separate sheet
  • Please highlight your answers on the sheet showing your work
  • Record the answers to each problem on this worksheet.
  • Staple the “work sheets” to this worksheet 
  • No work = No points!
  1. Consider the cross Aa Bb Cc ddEe x AA BB cc DD Ee
  2. What is the probability that any of the offspring will have the genotype AA BB cc Ddee?
  1. What is the probability of offspring that show every dominant trait?
  1. If the parent listed first is test-crossed, what is the probability of offspring homozygous recessive for every trait?’
  1. For the parent listed first, what is the probability of a gamete with all recessive alleles?
  1. The seeds from Mendel’s tall plants were round and yellow, with all three characters due to a dominant gene at each of the three independently assorting loci. The recessive genotypes, tt, rr, and yy produce dwarf plants with wrinkled and green seeds respectively.
  2. If true-breeding tall plants with round, yellow seeds are crossed with true-breeding, short plants with wrinkled, green seeds, what is the probability of plants that are tall with round, and yellow seeds in F2?
  1. What percentage of F2 is expected to be of the genotype Tt RRyy?
  1. Determine the phenotype ratio in the cross Tt rrYy X Tt Rr YY.
  1. Long-eared goats mated to short eared goat produce an ear of intermediate length in F1 and ¼ long, ½ intermediate, and ¼ short-eared goats in F2. Non-bearded male goats mated to bearded female goats produce bearded male progeny and non-bearded female progeny in F1. In F2, halfthe males and females are bearded, and half the males and females are non-bearded. A bearded male with ears of intermediate length whose father and mother were non-bearded, is mated with a non-bearded, intermediate-eared half-sib (half-sibling) with the same father, but out of adifferent, bearded mother.
  2. What is the probability of intermediate-eared, bearded male offspring?
  3. What is the probability of short-eared, non-bearded female offspring?
  1. A man of blood group B positive is being sued by a woman of blood group A negative for paternity. The woman’s child is blood group O negative.
  2. If this man actually is the father of this child, specify the genotypes of both parents.
  1. Assuming the couple had children, what are the expected phenotype ratios?
  1. Feather color in chickens is governed by a pair of co-dominant alleles such that BB = black, WW = white, and BW = black & white, described as blue. An independently segregating locus governs the length of leg; LL genotypes possess normal leg length, Ll genotypes produce squatty, shortlegged types called “creepers”, but homozygous ll genotypes are lethal. Please note: Only viable offspring are included in calculations. If blue creepers are crossed with blue creepers,
  2. Determine the probability of creepers of any color.
  1. Calculate the expected percentage of blue, normal-legged chickens.
  1. A sex-linked dominant trait found in humans is hypophosphatemia (low phosphate blood levels resulting in deformed bones, bowleggedness). If a bowlegged man marries a normal-legged woman, . . .
  2. What is the probability of a normal-legged daughter?
  1. What is the probability of a normal-legged son?
  1. In Labrador retriever dogs, the dominant gene Bdetermines black coat color and bbproduces brown. A separate gene, E, however, shows dominant epistasis over the Band balleles. If the dominant Eis present, B and b are expressed. The homozygous recessive form of this gene (ee) produces golden Labrador retrievers.
  2. Determine the probability that two black dogs, both heterozygous for both genes, would produce black puppies.
  1. Determine the expected phenotype ratios in the following cross: EeBb X eeBb
  1. What are the parental genotypes if two brown dogs produce a litter that includes golden puppies? What are the expected phenotype ratios for the litter?
  1. Examine the pedigree below. What is the path of inheritance for the trait shown? Identify the genotypes of eachindividual in the pedigree.
  1. Examine the pedigree showingan x-linked trait. Determine the genotype(s) for each of the following individuals:

  1. Examine the pedigrees below. First, identify all possible paths of inheritance from the list below. Then, circle the most probable path of inheritance: that is, the best fit, if applicable.

autosomal dominantX-linked recessiveY-linked

autosomal recessiveX-linked dominant