MacCallum means "son of Colm" and the name originates from St. Columba, whose name in Gaelic is "Colm".¹

Just as they pass their surnames, males also pass Y-chromosome DNA from father to son on down the male line.  All male surnamed MacCallum/McCallum/Malcolm and other variants are welcome to join the project!  ALL Clan MacCallum/Malcolm and listed surname variant descendants are welcome to join the MacCallum/Malcolm DNA Study if they order or have already taken Family Tree DNA's Family Finder autosomal DNA test or transfer their results into Family Tree DNA from Genographic, Geno 2.0 or 23andMe.