Effect of cousins marrying cousins

[mamoahina]

I managed to get the one Pitcairn person take an autosomal test and compare that person to two people whose 1 grandparent was from Norfolk island, of which was resettled by Pitcairn people in 1850.

[David Guetta]

I managed to get the one Pitcairn person take an autosomal test and compare that person to two people whose 1 grandparent was from Norfolk island, of which was resettled by Pitcairn people in 1850.

What were their ancestral breakdowns like, just out of curiosity?

[Alexandrina]

PITCAITN ISLANDERS & CHRISTIAN FLETCHER-To Norfolk Island

What were their ancestral breakdowns like, just out of curiosity?

The Pitcairner Islanders were/are YDNA wise descended from a small group of Englishmen who were mutineers against Captain William Blight of HMS Bounty. Bligh became a Governor of New South Wales Colony-(Australia). There were also a handful of Pacific Islanders- Tahitian /Samoan males and the nine English/Scot/Irish mutineers.

The 10-11 women were Pacific Islanders. This unique group intermarried over the past 200+ years & are now represented by communities living on Pitcairn & Norfolk Islands. Many members have recently departed for Australia , New Zealand and elsewhere however. Various newcomers added to the gene pool especially George Hun Nobbs , who became the Minister to the community.

The Pitcairn/Norfolk Islanders are a unique group with many members descended from the infamous Christian Fletcher, leader of the mutineers on the Bounty. His family are very well documented around Cockermouth area Cumberland England.

Founding surnames of the males were:
Buffett; Christian; Quintal; McCoy; Adams & Young. (Mills -line extinct?) Evans- & Nobbs & others later.

It would be very interesting indeed to see autosomal DNA chromosome browser clips of the autosomal results within this very endogamous population. The NOBBS YDNA would be particularly interesting for those descended from that line.

Alexandrina.

Alexandrina.

[LadyAlaise]

In my humble opinion...

There seems to be some dispute among the experts on this, but several have told me that a history of cousin marriage, especially when combined with very large family size, can "convince" the matching algorithm that the relationship is closer than it really is. This is certainly the case with descendants of my own French-Canadian ancestry.

I would agree; My Dad is Acadian French; I had him tested first via Ancestry; before I got his results I already knew by doing my paper trail Research (thank god for records and Stephen White) that my grandparents were cousins many ways; hitting each step along the way from 3rd through 11th cousins; even 8th cousins two different ways all through their lines; kind of an accepted fact in Acadian Genealogy. So I wondered how this would affect my Dad's and my own DNA; I had a good indication of how when I got my own matches on FTDNA; my TOP match (aside from my folks whom I have now transferred over) is a known 4th cousin once removed that FTDNA places at 2nd cousin-4th cousin range; we share like 4 or 5 sets of common ancestors; then I got my Dad tested at Ancestry; well I got his results and nearly chortled my coffee all over my laptop; he has 3,384 DNA Matches at 4th cousin or closer!
I like to call this the 'Fold-over effect'; like making a Japanese Samurai sword; folding the steel to make it stronger; having a lot of Endogamy can really confuse the DNA matching.
This all compared to my (mostly Irish; and Not Acadian thank god) Mom who only has 114 DNA matches on Ancestry.
LOL
So my answer to can Cousins marrying Cousins effect your DNA results?, would be; Depending on the level of Endogamy down the generations; a resounding Yes.

[thetick]

So my answer to can Cousins marrying Cousins effect your DNA results?, would be; Depending on the level of Endogamy down the generations; a resounding Yes.

I agree as following groups have seen this:

Jewish, Mennonites, Pakistani, Acadian. Pretty much any group that has cousin marriages over many generations.