Mendelian Genetics & Punnett Squares

Terms to know:  Chromosome, allele, phenotype, genotype, homozygous, heterozygous, purebred, hybrid

An example of setting up a Punnett Square for a mono-hybrid cross (one characteristic) of seed shape:

Genotype ratio:  1 : 2 : 1 ;  Phenotype ratio: 3 : 1

An example of a di-hybrid cross (two characteristics) between 2 individuals heterozygous for both traits (CcSs):

Phenotype ratio:  9 : 3 : 3 : 1