Chapter 9, Problem 16Q

A.

Summary Introduction

To determine: The reason for large differences between the synonymous and nonsynonymous rates of nucleotide substitution.

Introduction: A non-synonymous substitution is a nucleotide mutation that alters the amino acid sequence of a protein. It is contrasted with synonymous substitution or silent mutation, which do not alter the amino acid sequences.

B.

Summary Introduction

To determine: The way in which it is possible for the histone H3 gene to resist so effectively the nucleotide changes that can alter its amino acid sequence, if the rates of synonymous changes are about the same for all genes.

Introduction: Histone proteins are highly conserved in eukaryotes. They are found almost in equal quantity as of DNA in a cell. Histone proteins are responsible for the packing of chromatin into nucleosome. There are five different families of histone protein. These are H1, H2A, H2B, H3 and H4.

C.

Summary Introduction

To determine: The feature of the data obtained from experiment on H3 protein argues against the highly privileged nature of this protein.

Introduction: H3 protein is one among the five histone proteins. It is a structural variant of the histone protein that is involved in packaging the DNA molecules into a structure called nucleosomes.