Somatic intragenic recombination within the mutated locus BLM can correct the high sister-chromatid exchange phenotype of Bloom syndrome cells.

摘要: Cells from persons with Bloom syndrome feature an elevated rate of sister-chromatid exchange (SCE). However, in some affected a minority blood lymphocytes have normal SCE rate. Persons who inherit the gene BLM identical by descent common ancestor very rarely exhibit this high-SCE/low-SCE mosaicism; conversely, mosaicism arises predominantly do not share ancestor. These population data suggested that most whom exceptional low-SCE cells arise are homozygous for mutation at but instead compound heterozygotes. Following clue, we carried out genotype analysis loci syntenic 11 exhibited mosaicism. In five them, polymorphic distal to were heterozygous their high-SCE had become cells, whereas proximal remained heterozygous. observations interpreted mean intragenic recombination between paternally derived and maternally mutated sites within can generate functionally wild-type progeny somatic cell which such occurred. 30 refs., 3 figs., tabs.