title: Evidence for the inactivation of an X chromosome early in the development of the human female.
abstract: Studies of somatic tissues and cultured cells, including fibroblast clones, from human embryos heterozygous for the electrophoretic variants of glucose-6-phosphate dehydrogenase confirm that one X chromosome is inactivated very early in embryonic development and indicate that X inactivation has occurred in the majority of cells from a variety of tissues at least by 5 weeks from conception.
mesh_terms: D001797:Blood Protein Electrophoresis; D002999:Clone Cells; D004622:Embryo, Mammalian; D005260:Female; D005347:Fibroblasts; D014644:Genetic Variation; D005865:Gestational Age; D005954:Glucosephosphate Dehydrogenase / Q000032:analysis; D006579:Heterozygote; D006801:Humans; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic; D011247:Pregnancy; D012730:Sex Chromosomes
chemical_list: D005954:Glucosephosphate Dehydrogenase