Unit 8e-8g Study Guide

8e. Incomplete Dominance

• Scenario Identification: Identify scenarios describing incomplete dominance.
• Phenotype and Genotype:
  • Homozygous dominant leads to a specific trait.
  • Homozygous recessive leads to a different trait.
  • Heterozygous results in a unique trait.
• Punnett Squares: Practice determining offspring phenotypes and genotypes using Punnett squares.

Practice Problems:

1. Guinea Pigs Color: Crossing yellow (Y) with white (y) results in cream-colored offspring.
2. Snapdragons: Crossing pink snapdragons results in a 1:2:1 ratio of red, pink, and white in the F1 generation.
3. Bear Coat Color: Predict the appearance and probability of offspring coat color when crossing black and white bears.

8f. Codominance

• Scenario Identification: Identify scenarios describing codominance.
• Phenotype and Genotype:
  • Homozygous dominant leads to a specific trait.
  • Homozygous recessive leads to a different trait.
  • Heterozygous results in a unique trait.
• Blood Types:
  • Know the genotypes and phenotypes for blood types.
  • Use Punnett squares for blood type inheritance.

Practice Problems:

1. Blood Type Variety in Family: Examine if a couple can have four children with different blood types.
2. Blood Type A and O: Determine why a father with AB blood type can't have a child with blood type O.
3. Fish Pigmentation: Analyze a cross between red and blue fish to understand the phenotypes of offspring.

8g. Hardy-Weinberg Equilibrium

• Five Assumptions:
  1. No mutations
  2. Random mating
  3. Large population size
  4. No natural selection
  5. No migration
• Equations:
  • Equation for genotype abundance.
  • Equation for allele abundance.
• Calculations:
  • Calculate allele and genotype frequencies in populations.

Practice Problems:

1. Rabbit Population: Calculate the frequency of black and white fur alleles given a dominant black allele frequency of 0.7.
2. Fish Population: Determine the frequency of heterozygous individuals, given 16% are homozygous dominant and 36% are homozygous recessive.
3. Cow Herd: Determine allele frequencies when 84% have black spots and 16% have white spots.