The postulated X-inactivation center at Xq27 is most reasonably explained by ascertainment bias: heterozygous expression of recessive mutations is a powerful means of detecting unbalanced X inactivation.
Migeon
B R
BR
D002470:Cell Survival; D004303:Dosage Compensation, Genetic; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000166:cytology; D016532:Mucopolysaccharidosis II / Q000235:genetics*; D015983:Selection Bias; D017384:Sequence Deletion; D014960:X Chromosome