Highland & Island Emigration Society Records - free on Scotlands People.

[Skoosh]

 The use of surnames in the Highlands by ordinary folk is of fairly recent origin, the Anglicising of a people who used  Gaelic patronymics amongst themselves stemmed from the need to learn English to "get on in the world" or appear on a muster-roll, a rent-roll or a lease, not to mention a school-roll where the use of Gaelic was taboo.
 The tenantry often took the name of their laird or indeed were compelled to in some instances, so trying to make sense of all this by resorting to DNA & no paper-trail to back it up, is something of a Sisyphean task. 

Skoosh.

[Rosinish]

Thought I'd ask if there's any 'Smith' in the DNA links?

McArthur may have been a 2nd marriage i.e. step-father?

What was Duncan's occ. on John's marriage?

Annie

[McArthur1828]

Duncan is listed as deceased on John and Isabella’s marriage certificate. I haven’t been able to find any Smith’s in DNA links.

[Rosinish]

Duncan is listed as deceased on John and Isabella’s marriage certificate. I haven’t been able to find any Smith’s in DNA links.

A marriage usually gives the occ. of the deceased father?

Does the marriage state mother was Margaret McArthur M.S. Smith or just Margaret Smith?

Is it possible Margaret was not his mother, had his mother died when he was young?

Have you found the family on any census together to find out where he was born?

Annie