The Basics...

What is a pedigree?

A pedigree is a pictorial representation of familial relationships, similar to a family tree. You usually use a pedigree to track a particular trait of interest. For example, you may mark certain individuals in the pedigree that have a particular disease, like sickle cell anemia. You could also use a pedigree to track non-disease traits such as blue eyes, if you really wanted to. The advantage of drawing a pedigree is that it makes it easier to analyze a trait/disease for its inheritance pattern. The trait/disease may be autosomal or sex-linked and may be dominant or recessive. It is also possible that a disease is not inherited at all, but rather caused by a microbe or the environment. This should also be made more obvious by looking at the pedigree. Use the external links below to learn more about how to create and read a pedigree.

External Links

Pedigree Analysis 1 - use this link to learn the different symbols to use in a pedigree and basic differences between the pedigrees of autosomal dominant and autosomal recessive traits.
Pedigree Analysis 2 - use this site to learn more about reading pedigrees and to add in the complexities of sex-linked traits.
Pedigree Practice 1 - use this interactive to analyze three different pedigrees. Be sure to answer the 2-3 questions for each pedigree before you move on to the next.
Pedigree Practice 3 - four more problems with nice solutions explaining why a particular answer is correct.