allele origin somatic allele origin acquired We distinguish germline, somatic, and de novo allele origin based on a combination two key criteria - whether the allele *inherited* from a parent, and whether it is *heritble' by offspring. Somatic variants are neither inherited or heritable - having originated via a spontaneous mutation in a non-germ cell. By contrast, germline variants are both inherited (passed down from a parent) and heritable (passable down to offspring). De novo mutations are not inherited but are typically heritable, as they originated through a spontaneous mutation that made them present in germ cells. These acquired mutations are called 'somatic' because they typically affect somatic (non-germ) cells. But when spontaneous do mutations occur in the germ cells of an organism, these can be passed on to offspring in whom they will be considered de novo mutations. Derived from https://www.cancer.gov/publications/dictionaries/genetics-dictionary/def/somatic-variant and https://ghr.nlm.nih.gov/primer/mutationsanddisorders/genemutation Describes an allele that result from some spontaneous mutation event in a somatic cell after fertilization, and thus are not present in every cell in the body.