14503
Methylation of C5 of cytosines at CpG dinucleotide sites of the DNA is one of the most important factors regulating the expression of genes .
 Chemical: cytosines; Chemical: CpG dinucleotide
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: cytosines, CpG dinucleotide 
Answer:
 Chemical: cytosines; Chemical: CpG dinucleotide