Regions of DNA that apparently have no function and are replicated alongside the organism’s genes to be passed from parent to offspring. Transposons are good examples; certain other types of repetitive DNA also have ‘selfish’ characteristics, as do nonfunctional relict genes and pseudogenes. Selfish DNA is so called as it seemingly exists only to pass copies of itself from one generation to another; it does so by acting like a ‘molecular parasite’, using the organism in which it is contained as a survival machine. This is known as the selfish DNA theory. The greatest amounts of apparently selfish DNA are found in vertebrates and higher plants. Selfish DNA may indeed exist because the cell has no way of halting its increase in the genome as long as it poses no selective disadvantage. Alternatively, its function may simply be unrecognized. Transposons make up some 45% of the human genome, accounting for a large proportion of junk DNA. The term was coined by British evolutionary biologist Richard Dawkins (1941– ) in his book The Selfish Gene (1976).