Chapter 11, Problem 34A

Summary Introduction

To write:

A scenario for a genetic disorder and create a pedigree for the same.

Introduction:

Genetic disorders are diseases are caused by mutations in genes or DNA sequence. Common genetic diseases are cystic fibrosis, night blindness, and hemophilia.

Explanation of Solution

Cystic fibrosis is a genetic disorder that can be inherited by offspring. It affects the lungs and the digestive system. In this condition, the body produces thick mucus that clogs the lungs and the pancreas. Moreover, cystic fibrosis is an autosomal recessive disorder.

Suppose, in a family, both mother and father are heterozygous for cystic fibrosis. Then, their genotype must be Aa. ‘A’ is dominant or normal allele and ‘a’ is recessive allele or fatal allele for cystic fibrosis. One child of this parent is normal, two are carriers of disease, and one suffers from cystic fibrosis. The above scenario is depicted in the below pedigree analysis: