chromosome (in the nucleus of the red cell's precursor cell) contains the normal or defective G6PD allele. See also Sex-determination system Dosage compensation Barr body Heterochromatin Epigenetics Skewed X-inactivation Developmental disorders thought to be related to X-inactivation: Early infantile epileptic encephalopathy type 9 Frontonasal dysplasia References Further reading External links Molecular genetics Genetics Epigenetics Female Sex-determination systems