Offspring of Mendel's Dihybrid Cross

parent plant parent plant homozygous homozygous for purple flowers for white flowers 0 Meiosis in a and long stems and short stems homozygous indi- vidual results in one PPTT pptt type of gamete. X e A cross between two @ @ homozygous individuals yields offspring with one .PPTt. possible genotype. All d'hybr'd offspring that form in this i example are dihybrids @ . (heterozygous for two ® 6 genes) with purple flow- four types Of gametes ers and tall stems. e Meiosis in dihybrid individuals results in four kinds of gametes. gee W2: o If two dihybrid individuals are crossed (a dihybrid cross), he four types of gametes can meet up in 16 possible ways. Out of 16 possible genotypes of the offspring, 9 will result in plants that are purple-flowered and tall; 3, purple-flowered and short; 3, white-flowered and tall; and 1, white-flowered and short. Thus, the ratio of phenotypes in a dihybrid cross is 9:3:3:1.