Some Drew lines originate in England, others in Ireland. There may even be some which originate in Scotland. In tracing y-DNA, it can become confusing when unexpected matches occur, involving lines from two of these countries. The answer will most likely involve an early movement of a Drew ancestor, generally from England (often Devon) into Ireland. This doubtless occurred during "The Plantation" period under Cromwell. Here is a link that indicates there were Drew's moving from Devonshire England during the reign of Elizabeth the First.
http://www.landedestates.ie/LandedEstates/jsp/estate-show.jsp?id=2036
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