Name: _________________________
Date: ___________________ Per. ___
Pedigrees and Human Traits
Directions: Read the section on Human Pedigrees in the textbook on pp. 396-397 and
answer the questions about the pedigree below.
1. What does a square in the pedigree represent?
2. What does a circle in the pedigree represent?
3. How many children do individuals I1 and I2 have?
4. Who has this trait?
To determine the inheritance pattern of the trait shown in a pedigree you have to
observe the number of individuals who have the trait, you have to determine
whether the trait appears in every generation, and you have to see if more males
or more females have the trait. Traits of dominant inheritance will appear in
every generation and many individuals will have the trait. Recessive traits skip
generations and fewer individuals have the trait as compared to a dominant trait.
Sex-linked traits are classified as dominant or recessive and more males have the
trait then females.
5. What is the inheritance pattern of the pedigree above?