13825
Lineage - tracing studies using sequential administration of thymidine analogs , rat insulin 2 promoter - driven cre - lox , and low - frequency ubiquitous cre - lox reveal that PDL does not convert progenitors to the beta - cell lineage .
 Chemical: thymidine
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: thymidine