ABSTRACT
By the end of the 20th century most evolutionists accepted that non-selective processes – genetic drift and random fixation – are responsible for evolutionary change at the molecular level, and that most of the mutational changes in the DNA are neutral or slightly deleterious. One mechanism which enables the accumulation of ‘small’ genetic changes – and can in time cause major evolutionary alterations – is gene duplication. The most commonly-used model for evolution by neutral mutations is the infinite-alleles model, originally suggested as an explanation for the large amount of electrophoretic variation in natural populations. Molecular research indicates that DNA sequences which code for proteins are separated by large sections of non-coding nuclear DNA. The most commonly-used model for evolution by neutral mutations is the infinite-alleles model, originally suggested as an explanation for the large amount of electrophoretic variation in natural populations.
