Genetic research. Helix of DNA (deoxyribonucleic acid) over a DNA autoradiogram. DNA consists of a helix formed by twisting sugar-phosphate strands that are joined by pairs of nucleotide bases. The pairs of bases are seen as the struts on the DNA 'ladder'. The bands (black) of the autoradiogram reveal the genetic data encoded in a sample of DNA (deoxyribonucleic acid). The bands correspond to the nucleotide bases in DNA, and the banding pattern shows the sequence of the bases. It is this sequence that forms a genetic code that is unique for every individual. DNA is a fundamental molecule that controls the development and functioning of every living organism.