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MDR - ADH origin ( s ) , at a fourth stage , may also be further resolved in multiple or extended modes , but the classical liver MDR - ADH of the liver type can still be traced to a gene duplication ~ 550 MYA ( million years ago ) , at the early vertebrate radiation , compatible with the post - eon - shift , " Cambrian explosion " .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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