PUNNETT SQUARE PRACTICE SHEET

  1. A woman with Brown (Bb) eyes is expecting a child with her husband who green eyes (gg). Using a Punnett square, determine the chances of this couple having a baby with: A. green eyes? B. Brown eyes? C. Pure brown eyes?
  1. This same couple want to know what color hair their child may have. Mom has light brown hair (Hh) and dad also has Light brown hair. If sandy blonde hair is (hh) and Dark brown hair is (HH), is the possibility of them have a child with:

1. Light brown hair? 2. Darkbrown hair? 3. Sandy blonde hair?

Use the Punnett square to determine this.

  1. A female alligator has tan skin (Tt) and brown eyes (Bb) mates with a male that has Dark brown skin (TT) and brown eyes (Bb). Using the Punnett square how many of their off spring will have:

A. Tan skin and Brown eyes? B. Dark brown skin and Brown eyes?

If the combination of (bb) represents pink eyes, how many of their off spring will exhibit this trait?

  1. A female alligator has tan skin (Tt) and brown eyes (Bb) mates with a male that the exact same genetic make up. And knowing that albinism is (ttbb) how many of their off spring will exhibit the following characteristics: (use the Punnett square to determine this)
  1. Tan skin and brown eyes?
  2. Dark brown skin and brown eyes?
  3. Tan skin and red eyes?
  4. Dark brown skin and red eyes?
  5. White skin and brown eyes?
  6. White skin and red eyes?
  1. A husband and wife have 3 children (all are boys). They are expecting another child (their fourth). What are the odds of them having a girl this time? Use the Punnett square to answer this question. Provide an argument as to why you believe that your answer is correct (Males = [XY] and Females = [XX]).