1662
Such alleles have not been observed among more than 900 normal and SBMA X-chromosomes that have been examined.
 ( DNA: SBMA X-chromosomes, 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: SBMA X-chromosomes, None) 