ABSTRACT
Virtually everything we know about genomes and genome expression has been discovered by scientific research: theoretical studies have played very little role in this or any other area of molecular and cell biology. It is possible to learn facts about genomes without knowing very much about how those facts were obtained, but in order to gain a real understanding of the subject we must examine in detail the techniques and scientific approaches that have been used to study genomes. The next five chapters cover these research methods. First, in this chapter, we examine the techniques, centered on the polymerase chain reaction and DNA cloning, that are used to study DNA molecules. These techniques are very effective with short segments of DNA, including individual genes, enabling a wealth of information to be obtained at this level. Chapter 3 then covers the methods that are used to construct maps of genomes, and Chapter 4 describes the methods used to sequence DNA molecules and to assemble the short sequences generated by these methods into the immensely long sequences that make up individual chromosomes and entire genomes. Finally, in Chapters 5 and 6, we will look at the various approaches that are used to locate the positions of genes in a genome sequence and to identify the functions of those genes. As you read through these chapters, you will begin to appreciate that understanding the structure and function of an individual genome is a major undertaking and that research is currently in the middle of an exciting discovery phase, with new techniques and new approaches revealing novel and unexpected aspects of genomes almost every week.
