Pedigree Analysis Help
A pedigree is a systematic listing (either as words or as symbols) of the ancestors of a given individual, or it may be the "family tree" for a large number of individuals. It is customary to represent females as circles and males as squares. Matings are shown as horizontal lines between two individuals. The offspring of a mating are connected by a vertical line to the mating line. Different shades or colors added to the symbols can represent various phenotypes. Each generation is listed on a separate row labeled with Roman numerals. Individuals within a generation are labeled with Arabic numerals. Pedigree analysis is used in place of breeding studies, particularly in humans, where experimental matings are not possible. A pedigree can help determine the genetic basis of a particular trait or disease.
EXAMPLE 2.39 Let solid symbols represent black-coated guinea pigs and open symbols represent white-coated guinea pigs; circles represent females and squares represent males.
Summary of pedigree analysis:
Practice problems for these concepts can be found at: