ABSTRACT
A mosaic is formed by two or more genetically different populations of cells originating from a single healthy wild-type zygote. It is developed from an early-stage embryonic mutation, called a somatic mutation. Mosaics are well known in biology, especially in plants, fruits, and animals such as insects, (e.g., Drosophila species), but by contrast, in humans they represent recent knowledge (published for the first time, independently, by Jackson and Happle in 1976) and even more recent understanding. From 1983 onward, many molecular biology studies have attempted to explain the pathogenesis of this phenomenon.
