HUMAN PEDIGREE CHARTS aka Family Trees Human traits are difficult to study for several reasons. 1. Humans reproduce slowly 2. Humans produce only a few offspring at a time 3. Humans usually do not have large number of offspring Human traits must be studied through population sampling and pedigree analysis. Pedigree—a diagram that shows the phenotype of a particular genetic trait in a family from one generation to the next. Genotypes for individuals can often be determined with an understanding of inheritance and probability
SYMBOLS USED IN PEDIGREES Male Female Affected male Affected female Mating
Parents Siblings
Death
DETAILS Every line represents a generation. Each generation is marked with a roman numeral Each individual is marked with an Arabic number When possible, children are placed from oldest to youngest, left to right