Biology – The Continuity
of Life

Objective 2
Identify human genetic conditions using a
pedigree.
Pedigrees

Why are they Used?
– To trace inherited genetic conditions
through a family
– To learn how a trait is passed on (…is it
dominant, recessive, sex-linked…?)
– To make predictions about the genetics
of future family members
(Autosomal) Recessive
Pedigree
Sex-Linked Trait Pedigree
Pedigrees

How are they Made?
– Since every family is different…
– …just start with known family members,
using correct symbols, shading,
genotypes, and phenotypes
– Use genetic knowledge to predict what
traits offspring can possibly inherit