Chapter 14, Problem 22PIAT

Summary Introduction

To review:

The reason behind the occurrence of color blindness in the son without Adrenoleukodystrophy (ALD).

Introduction:

Adrenoleukodystrophy (ALD) is a type of X-linked disorder. It occurs as a result of mutation in the ABCD1 gene, which is present on the Xq28 chromosome. Furthermore, the nonfunctioning of these enzymes damages the myelin sheath present on the axon, which further causes degeneration of neuron.

A woman is heterozygous for a colorblindness allele. At a site on the chromosome with the color blindness allele, a new mutation occurs causing ALD, creating one chromosome with an allele for color blindness and an allele for ALD. Woman bears a colorblind child but does not have ALD.