A DNA surname project for for Hallorans and O'Hallorans and genetic relatives. Participants with Halloran and O'Halloran ancestry are encouraged to join the project. Variant spellings are also likely to be genetically related. At this time, those who have tested Y-DNA, mtDNA, X-DNA, and autosomal DNA should feel welcome. The best results for the surname study are expected to come from male Y-DNA Halloran participants.