Pedigree Analysis * A pedigree is a family tree that describes the interrelationships of parents and children across generations * Inheritance patterns of particular traits can be traced and described using pedigrees * Pedigrees can also be used to make predictions about future offspring * We can use the multiplication and addition rules to predict the probability of specific phenotypes Recessively Inherited Disorders * Many genetic disorders are inherited in a recessive manner * These range from relatively mild to life-threatening The Behavior of Recessive Alleles * Recessively inherited disorders show up only in individuals homozygous for the allele * Carriers are heterozygous individuals who carry the recessive allele but are phenotypically normal