Chapter 18.6, Problem 2CC

Summary Introduction

To explain:

Why flies and mice are so different, even though the DNA sequences called home boxes are common.

Introduction:

The genes that regulate the structural development in many plants, echinoderms, insects and mammals are known as homeotic genes. The regulation of homeotic genes is done through transcription factors programming and these transcriptional factors affect the homeotic genes via genetic regulatory pathways.

Mutations in these genes result in displacement of the body parts. For example, antennae displaced in the posterior part of the fly instead the head portion. The homeotic genes are mainly of two types: ParaHox and Hox which play important role in segmentation.