1663
Comparison of the SBMA sperm typing results with mutation frequency data on normal alleles supports the hypothesis that trinucleotide repeat expansions may have a different molecular origin than contractions .
 ( cell type: sperm, None) , ( DNA: trinucleotide repeat, 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:
 ( cell type: sperm, None) , ( DNA: trinucleotide repeat, None) 