A Reproductive Lexicon


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Mosaicism exists when cells undergo changes during development such that one group of cells differs from a neighboring group. It can occur in both somatic and germ cells. Mosaicism can be caused by spontaneous DNA mutations (in either nuclear or mitochondrial DNA), spontaneous reversion of an existing DNA mutation, epigenetic changes in chromosomal DNA, and chromosomal abnormalities. Symptoms that occur as a result of mosaicism depends on the extent of the mosaic cell population. Mosaicism is important in terms of human disease. It also provides variations at the molecular level among humans, including between identical twins.