Generation

A family tree, also called a pedigree diagram, traces a characteristic through related individuals. It combines two kinds of information: the lines show family relationships, while the symbols show each person’s sex and whether they have the phenotype being investigated. This allows inheritance to be followed across generations even when the underlying alleles cannot be observed directly.

Repeating this selection and breeding over many generations makes the characteristic more common in the resulting population. It does not mean that every offspring will have the desired characteristic after one cross.