Mendel’s dihybrid cross experiment demonstrates that characteristics are inherited independently. He used two characteristics in the experiment: seed shape and seed colour. While the round shape (RR) dominates over the wrinkled shape, the colour yellow (YY) dominates over green (YY) (rr). There were nine plants with round yellow (RRYY) seeds, three plants with round green (RRyy), three plants with wrinkled yellow (rrYY), and one plant with wrinkled green seeds among the F2 progeny of the dihybrid cross (rryy).He also observed that while the round green and wrinkled yellow are new, the wrinkled greens and round yellow are parental combinations. Four different types of gametes were produced by a dihybrid cross between two seeds with dominant traits (RRYY) and non-dominant traits (rryy) (RY, Ry, rY and ry). This indicates that each gamete segregates separately from the others, with a frequency of 25% of all gametes generated.
