Pedigree Analysis Help

By — McGraw-Hill Professional
Updated on Sep 20, 2011

Pedigree Analysis

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.

Pedigree Analysis

Summary of pedigree analysis:

Practice problems for these concepts can be found at: 

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