Chapter 11, Problem 16STP

Summary Introduction

To determine:

The kind of inheritance pattern took place for the given disease.

Introduction:

Each organism receives two version of the same gene, and these versions are termed as alleles. If different alleles are present in the gene, then the dominant allele will express itself and mask the effect of recessive allele. So, there are two types of alleles, dominant allele and recessive allele.

Explanation of Solution

Two parents have a mild form of genetic disease, but their child is born with a very severe form of the same disease. This disease shows codominance pattern of inheritance. In codominance inheritance, when an individual is heterozygous, then both the dominant and the recessive alleles express themselves. Due to which, the genetic disease shows only mild or no symptoms. But, if the individual is recessive homozygous in nature, then the genetic disease can be proved fatal for the person.

In the above case, the parents may be heterozygous for the genetic disease, but their child may have born with homozygous form of fatal allele. Due to which, he has severe form of that genetic disease.