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: The rs4704559 G allele was associated with a lower prevalence of dyskinesia ( prevalence ratio ( PR ) = 0 . 615 , 95 % confidence interval ( CI ) 0 . 426 - 0 . 887 , P = 0 . 009 ) and visual hallucinations ( PR = 0 . 515 , 95 % CI 0 . 295 - 0 . 899 , P = 0 . 020 ) .
### Output Text:
The rs4704559 G allele was associated with a lower prevalence of dyskinesia ( prevalence ratio ( PR ) = 0 . 615 , 95 % confidence interval ( CI ) 0 . 426 - 0 . 887 , P = 0 . 009 ) and visual hallucinations ( PR = 0 . 515 , 95 % CI 0 . 295 - 0 . 899 , P = 0 . 020 ) . 