6282
AID initiates somatic hypermutation and class switch recombination ( CSR ) by deaminating cytosine to uracil in specific immunoglobulin ( Ig ) gene regions .
 Chemical: cytosine; Chemical: uracil
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: cytosine; Chemical: uracil