3178
Repetitive sequences are present in at least three introns of the cytochrome P - 450PBc2 gene , but not in exons or the 5 ' - flanking region .
 cytochrome P - 450PBc2 gene
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 cytochrome P - 450PBc2 gene