12666
We failed to find any correlation between age and X- chromosome inactivation pattern (r = 0.17), even subdividing the subjects in different age groups according to the criteria used by other researchers , and therefore reaffirm that, when tested for with well-standardized and accurate criteria, extremely unbalanced inactivation of the X chromosome is a truly uncommon phenomenon in normal women .
 ( DNA: X chromosome, None) , ( DNA: X- chromosome, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( DNA: X chromosome, None) , ( DNA: X- chromosome, None) 