Ah, yes. The penny's dropped now

Of course. Ye Dad is / was a Mackenzie, as was his Dad, so on and so forth. Men pass their surnames on as well as the male gene. With ye now. And suddenly, one of ye Dads Dads Dads, somewhere back there, wasn't a Mackenzie but a Rose. I see ye problem! Blimey!
Like C - Side says; It could be way back. Then again though, it could be just Gt. or two back. For example; Maybe one of ye Gt. Gt. what ever Grand Dads changed his surname for some reason?
Anyway, look on it a a fascinating discovery and nice little project for ye. Just carry on doing what we all do. Keep tracing ye tree
'Backwards' and up that Mackenzie line. Ignore the Rose question for now. Just work ye own pedigree. One day, in so doing, ye might make some gob smacking discovery and all will be revealed.
Or this changeover may have occurred in the thirteenth century ~ in which case ye haven't got a cellophane rats chance of ever discovering it!
