In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Patients were genotyped for rs4704559 , rs10942891 and rs4704560 by allelic discrimination with Taqman assays .
### Output Text:
Patients were genotyped for rs4704559 , rs10942891 and rs4704560 by allelic discrimination with Taqman assays . 