The developmental basis for germline mosaicism in mouse and Drosophila melanogaster

摘要: Data involving germline mosaics in Drosophila melanogaster and mouse are reconciled with developmental observations. Mutations that become fixed the early embryo before separation of soma from may, by sampling process development, continue as part and/or differentiate into any somatic tissue. The cuticle adult D. melanogaster, because segmental can be used to estimate proportion mutant nuclei embryo, but most tissues germlines both species samples too small representative embryo. Because sample cells/nuclei remain after species, mosaic have percentages cells vary widely, a mean 50% an unusual platykurtic, flat-topped distribution. While leads similar statistical results for their patterns development very different. In first differentiation is continuing only two four nuclei, whereas cleavage nuclei. presence mosaicism independent eye, head, thorax. This independence was determine mutations occur at embryonic cell divisions still average germ when mosaic; however, later mutation occurs, higher completely nonmutant germlines. contrast does not separate produces inner mass Following formation primitive streak, primordial develop base allantois among clonally related cells, providing same distribution melanogaster. during greatly underestimated. For example, DNA lesion postmeiotic gamete becomes dominant F1 may produce individual line relevant tissue or, alternatively, no detecting until F2. cases would classified complete F2, respectively, recognized origin. mammalian there more opportunities correlation between mammal than Drosophila. However, tissue, like blood, derived samples, many individuals test negative blood either or entirely mutant.