3010
The small size and placement of the mutagenesis marker ( the supF suppressor tRNA gene from Escherichia coli ) within the vector substantially reduced the frequency of spontaneous mutations normally observed after transfection of mammalian cells with plasmid DNA ; hence , UV - induced mutations were easily identified above the spontaneous background .
 supF suppressor tRNA gene from Escherichia coli
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 supF suppressor tRNA gene from Escherichia coli