1020
In conclusion , to study and overcome TI region - based expression problems it is worthwhile to start out with a versatile vector containing exhaustive mutations in the periShine - Dalgarno sequences ; as a rule the coding MTI subregion can be kept unchanged .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
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