4683
This polymorphism at residue 57 is a recurrent feature of HLA-DQ evolution , occurring in multiple distinct allelic families , which implies a functional selection for maintaining variation at this position in the class II molecule .
 protein: class II molecule
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: class II molecule 
Answer:
 protein: class II molecule