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The Ups & Downes of atDNA matching.

Genetic Genealogy Ireland 2016

1:00 p.m. Sunday 23 October 2016

Dodder Room A, Main and Industries Halls, Royal Dublin Society

by Paddy Waldron

WWW version:

http://pwaldron.info/GGI2016/

YouTube versions:

https://www.youtube.com/watch?v=FXG81CRSS9s

https://www.youtube.com/watch?v=2ZYme-oVxwY

Background

I have been My presentation will combine examples of the successful application of autosomal DNA matching from my own experience with my thoughts on the statistical shortcomings of the current matching methodology.

A little theory

Rules of thumb

GEDmatch.Com Autosomal Comparison - V2.1.1(c)

Comparing Kit M701774 (*gerardcorcoran) and F310654 (*DD Paddy Waldron: FTDNA)

Minimum threshold size to be included in total = 500 SNPs
Mismatch-bunching Limit = 250 SNPs
Minimum segment cM to be included in total = 1.0 cM


Chr Start Location End Location Centimorgans (cM) SNPs
1 5,672,600 7,467,551 3.5 526
1 216,591,255 219,036,547 1.7 589
2 28,531,914 30,875,988 3.9 837
2 31,092,028 33,563,465 2.0 608
2 72,124,459 74,967,080 3.8 500
2 133,833,374 137,630,441 3.4 992
2 195,572,268 198,893,685 2.6 611
3 99,191,645 102,077,330 1.1 588
3 173,868,387 176,283,454 4.0 546
4 127,857,882 131,202,505 2.4 558
6 34,071,479 36,335,286 2.0 540
6 57,363,111 66,140,501 1.5 594
8 74,492,350 78,058,946 2.0 733
10 21,321,216 24,515,358 2.7 634
10 91,313,757 105,795,487 13.3 3,773
11 40,141,830 42,881,983 2.1 670
12 20,479,649 21,446,849 1.7 625
12 93,471,271 96,520,684 4.2 933
13 61,812,542 65,035,563 1.5 618
13 107,813,761 109,189,743 3.6 546
14 72,035,860 74,062,136 2.2 511
15 40,476,285 43,755,827 1.3 560
15 52,182,570 55,581,057 2.4 798
17 15,189,078 18,639,796 3.3 611
17 30,139,136 32,880,531 3.4 576
17 37,380,586 41,144,579 2.2 719
20 6,694,498 8,386,742 4.3 524
Largest segment = 13.3 cM
Total of segments > 1 cM = 82.1 cM
27 matching segments

677571 SNPs used for this comparison.

Phasing and Triangulation

Example I: Clancys and Marrinans

Example II: From A Little Cottage In Clare: The Down(e)s family

Example III: Are your parents related?

Example IV: My Lynch ancestor was Irish - what townland was he from?

Example V: An unresolved adoption

Example VI: An easily resolved adoption

Example VII: A complicated adoption

Example VIII: The Talty millions - did the wrong people get the inheritance?

Example IX: The first theory is not always the correction explanation - Kett of East Clare and Kett of West Clare

Example X: The first theory is not always the correction explanation - the two Tom Comers

Example XI: Autosomal surname markers - Marrinan

Example XII: Dubious record-keeping - who's the odd one out in the Reidy dynasty?

Example XIII: Marriage Dispensation - Ryan/O'Dea

Example XIV: Marriage Dispensation - Stenson/Durcan

Example XV: West Clare ethnicity

Example XVI: 1916

Further reading