ABSTRACT
Life as we know it is specified by the genomes of the myriad organisms with which we share the planet. Every organism possesses a genome that contains the biological information needed to construct and maintain a living example of that organism. Most genomes, including the human genome and those of all other cellular life forms, are made of DNA (deoxyribonucleic acid), but a few viruses have RNA (ribonucleic acid) genomes. DNA and RNA are polymeric molecules made up of chains of monomeric subunits called nucleotides. Each molecule of DNA comprises two polynucleotides wound around one another to form the famous double helix, in which the two strands are held together by chemical bonds that link adjacent nucleotides into structures called base pairs.
