Genetic Diagrams

• What do genetic diagrams show?

  Combinations of alleles from parents
• What does the dominant allele 'A' code for in mice?

  Normal amounts of average muscle
• What does the recessive allele 'a' code for in mice?

  Muscular mass
• How are alleles represented in genetic diagrams?

  As uppercase and lowercase letters
• What does a homozygous normal mouse's genotype look like?

  Capital A, capital A
• What is the phenotype of a homozygous muscular mouse?

  Muscular
• How do you find the gametes from a parent's genotype?

  Split the letters into separate circles
• What do you do to find the offspring's genotypes?

  Combine the gametes from both parents
• What is the genotype of all offspring from a homozygous normal and a homozygous muscular mouse?

  All are heterozygous
• What phenotype do all heterozygous offspring express?

  Normal phenotype
• What is a Punnett square used for?

  To show genetic combinations visually
• How does a Punnett square differ from a genetic diagram?

  Punnett squares are simpler to draw
• What is the ratio of normal to muscular mice from two heterozygous parents?

  Three to one ratio
• What is the probability of having muscular offspring from two heterozygous parents?

  One in four or 25%
• What is the genotype of the offspring when two heterozygous mice mate?

  One homozygous dominant, two heterozygous, one homozygous recessive
• What environmental factors can affect traits like height?

  Food and sleep during childhood
• What are the five main steps to draw a genetic diagram?

  1. Identify parents' phenotype and genotype
  2. Determine gametes' genotypes
  3. Combine gametes to find offspring's genotypes
  4. Determine offspring's phenotypes
  5. Present the results in a diagram
• What are the strengths and weaknesses of genetic diagrams and Punnett squares?

  Strengths:

  • Genetic diagrams show allele combinations
  • Punnett squares are simpler to draw

  
  

  Weaknesses:

  • Genetic diagrams can be complex
  • Punnett squares don't show phenotypes