Instructions:

Select the type of trait to investigate in a pedigree.
Drag one male and one female pedigree symbol to the parents in the first generation.
Select the number children they have and observe the phenotypes and genotypes of these offspring.
Repeat by selecting mates and the number of children for individuals in subsequent generations.

Type of Trait

Autosomal Dominant
Autosomal Recessive
Sex-Linked Recessive

Pedigree Symbols

Male	Female

Homozygous Unaffected

Heterozygous Affected

Homozygous Affected

Autosomal recessive diseases are more rare because the offspring need to inherit the abnormal allele from both parents. Autosomal recessive diseases are more common in matings between close relatives because the fusion of two gametes carrying the rare recessive allele is more likely when the parents are related.

Example: Familial hypercholesterolemia

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