9081
We identified > 25 , 000 distinct RNA species in human fibroblasts that contained non - colinear exons ( a " backsplice " ) and were reproducibly enriched by exonuclease degradation of linear RNA .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None