Becker's World of the Cell 9th Edition by Lewis Kleinsmith, Jeff Hardin, Gregory Paul Bertoni

Exercise 8

QUANTITATIVE Punnett Squares as Genetic Tools. The genetic characters of seed color (where Y is the allele for yellow seeds and y for green seeds)and seed shape (where R is the allele for round seeds and r for wrinkled seeds)were used by Mendel in some of his crosses.
(a)Mendel performed a one-factor cross between parent plants that were both heterozygous for seed color Yy × Yy. Using a Punnett square, explain the 3:1 phenotypic ratio Mendel observed for the offspring of such a cross.
(b)Mendel went on to perform a two-factor cross between plants heterozygous for both seed color ( Yy )and seed shape (Rr). How does the Punnett square of Figure 25-26 reflect Mendel's law of independent assortment
(c)Complete the Punnett square of Figure 25-26 by writing in each of the possible progeny genotypes. How many different genotypes will be found in the progeny In what ratios
(d)For the case of Figure 25-26, how many different phenotypes will be found in the progeny In what ratios