7449
Although post - translational addition of methyl groups to the histone lysine has been discovered three decades ago , the importance of this epigenetic modification has emerged only in the last few years .
 Chemical: methyl; Chemical: lysine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: methyl; Chemical: lysine