<P> In 1972, Walter Fiers and his team at the University of Ghent were the first to determine the sequence of a gene: the gene for Bacteriophage MS2 coat protein . The subsequent development of chain - termination DNA sequencing in 1977 by Frederick Sanger improved the efficiency of sequencing and turned it into a routine laboratory tool . An automated version of the Sanger method was used in early phases of the Human Genome Project . </P> <P> The theories developed in the early 20th century to integrate Mendelian genetics with Darwinian evolution are called the modern synthesis, a term introduced by Julian Huxley . </P> <P> Evolutionary biologists have subsequently modified this concept, such as George C. Williams' gene - centric view of evolution . He proposed an evolutionary concept of the gene as a unit of natural selection with the definition: "that which segregates and recombines with appreciable frequency ." In this view, the molecular gene transcribes as a unit, and the evolutionary gene inherits as a unit . Related ideas emphasizing the centrality of genes in evolution were popularized by Richard Dawkins . </P> <P> The vast majority of living organisms encode their genes in long strands of DNA (deoxyribonucleic acid). DNA consists of a chain made from four types of nucleotide subunits, each composed of: a five - carbon sugar (2' - deoxyribose), a phosphate group, and one of the four bases adenine, cytosine, guanine, and thymine . </P>

Where are genes found in a cell and what are they composed of