Understanding DNA: The Molecule and How it Works

Book Preface

This is a book about DNA, the most central substance in the workings of all life on Earth. It is a book about the way in which DNA works at a molecular level. We have used the title Understanding DNA… because our subject has now reached the stage where many aspects of it are well enough understood for us to be able to give a clear and uncluttered presentation of the main ideas. But we shall not disguise the fact that there is still a great deal which is not known or understood.

The book can be read at two different levels. First, it can be taken as an easy-to-read textbook for undergraduate or graduate students of chemistry and biology at university. Second, it may be read by ordinary people who have no prior knowledge of biochemistry, but who want to understand something of the fundamental processes of life. The sort of people we have in mind here are those who have learned something about DNA from popular magazines, newspapers, and TV programs. They know, for example, that DNA contains the ‘genes’ of classical genetics – those units of inheritance which pass on characteristics such as red hair or a long nose from parent to child, or even crippling diseases such as sickle-cell anemia or thalassemia. They probably also know that DNA is a long molecule, like a computer tape – the tape which tells our bodies how to grow and how to digest food and (perhaps) how to behave. And they may even know, if they are into quiz games and the like, that the initials ‘DNA’ stand for ‘Deoxyribo-Nucleic Acid,’ a certain kind of acid found in the cell nucleus, which was first identified over 100 years ago. People like this, who are curious to know more, will be able to learn a lot from this book about how DNA performs its tasks in our bodies at a molecular level.