Chapter 11, Problem 29A

Summary Introduction

To describe:

Characteristics associated with Down syndrome

Introduction:

Nondisjunction may result in an extra copy of a particular chromosome. Having a set of three chromosomes of one kind is known as trisomy. Alteration in chromosome number causes serious human disorders. In some people there is an extra copy of chromosome 21. This causes a chromosomal disorder called Down syndrome. It is also called trisomy 21.

Answer to Problem 29A

The characteristics of Down syndrome include distinctive facial features, short stature, heart defects and mental disabilities.

Explanation of Solution

The following karyotype is of a person suffering from Down syndrome.

A child with Down syndrome will have deformed facial features such as flat round face, small nose, ears and mouth and almond shaped eyes with skin folds in inner corner of eyes. The child will be of short height and may suffer from heart problems. There may be developmental delays and intellectual disability too.