Genomics in the AWS Cloud

CHAPTER 2A Crash Course in Molecular Biology

To properly analyze genomes, you need to understand some key biology concepts. Biology is a vast field, and this chapter focuses on areas that are fundamental for extracting meaningful information from genomes.

DNA

As you are probably aware, your genome encodes all the information necessary to build and maintain your body. It is composed of a series of about three billion letters, which can be either A, G, C, or T, and is stored inside the nucleus of each of your three trillion nucleated cells. Red blood cells do not have a nucleus and therefore are your only cells without a copy of your genome.

Note that all living organisms—such as animals, plants, fungi, or bacteria—also have a genome, composed of the same letters A, G, C and T. This book focuses on the analysis of the human genome, but all concepts and techniques are applicable to other species. You can apply them to the analysis of the genome of your cat, goldfish, potted plant, or slime mold growing in your front lawn. In genomics, it is sobering to see that humans are just a life species among many others.

Physically speaking, your genome is encoded into chains of repeating subunits called nucleotides. Each nucleotide consists of a sugar group, a phosphate group, and a base that can be either adenine (A), guanine (G), cytosine (C), or thymine (T). The sugar group is called deoxyribose; hence, these long molecules are named deoxyribonucleic acid (DNA). A chain of nucleotides ...