Figure 6.3: The Punnett Square of a cross between two purple flowers (Bb) ( 18 )- A Punnett square is useful for predicting the outcomes of crosses.
Review Questions
- What is the term for the offspring of a cross, or the first generation?
- What is the F2 generation?
- Who is considered the father of genetics?
- Why did Mendel select peas as a model for studying genetics?
- In peas, yellow seeds (Y) are dominant over green seeds (y). If ayy plant is crossed
with aYY plant, what ratio of plants in the offspring would you predict? - In peas, purple flowers (P) are dominant over white flowers (p). If appplant is crossed
with aPpplant, what ratio of plants in the offspring would you predict? - In guinea pigs, black fur (B) is dominant over white fur (b). If aBBguinea pig is
crossed with a Bbguinea pig, what ratio of guinea pigs in the offspring would you
predict? - In guinea pigs, smooth coat (S) is dominant over rough coat (s). If aSS guinea pig
is crossed with assguinea pig, what ratio of guinea pigs in the offspring would you
predict? - In humans, unattached ear lobes are dominant over attached ear lobes. If two parents
have attached earlobes, what is the predicted ratio in the offspring? - Why would it be much easier to study genetics in pea plants than in people?
Further Reading / Supplemental Links