Chapter 13, Problem 9STP

Summary Introduction

To explain:

The meaning of the symbols in the last generation of the given pedigree.

Introduction:

Scientists study family history using a diagram that traces inheritance of a particular trait through several generations. Such diagrams are called pedigree. A pedigree uses symbols to illustrate the inheritance of trait. By analyzing the pedigree we can predict if the person will suffer from disease or will be a carrier of the disease or will be disease free.

Answer to Problem 9STP

- This represents a male who is homozygous for the disease/ expresses the disorder

- This represents a normal male who is not affected by the disease

A partially filled circle represents a female who is heterozygous for the trait and is a carrier of the disease.

Explanation of Solution

  

The given pedigree illustrates inheritance of a dominant genetic disorder. The last generation shows a dark square or completely filled square, a half filled circle and an unfilled square.

Males are represented by squares and females are represented by circles. One who expresses the trait is represented by a dark or filled square or circle. In a pedigree diagram, an unfilled square or circle does not express the trait. A partially filled square or circle does not express the trait but is a carrier of the trait.