8183
Nucleotide sequence analysis of R has revealed similarities to the R1 plasmid found in some South American maize races with RU cytoplasm , to the M1 plasmid found in one source of Zea luxurians teosinte , to the atp9 mitochondrial gene and its 3 ' flanking sequence , and also to a region 3 ' to the orf221 gene .
 atp9 mitochondrial gene, orf221 gene
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 atp9 mitochondrial gene, orf221 gene