Case studies using genealogical junctions among unplaced DNA matches to identify unknown ancestors.
(2023) In Journal of Genetic Genealogy 11(1).- Abstract (Swedish)
- The present paper describes case studies where the purpose was to identify two unknown ancestors: the author’s paternal grandfather [FF] and his paternal grandmother’s maternal grandfather’s father [FMMFF]. A four-step method was used: (1) The author’s and his brother’s closest atDNA matches were identified, and the genealogical relationships to these matches were searched for by a comparison with their family trees. Those atDNA matches for which no explanatory genealogical relationship could be found were named unplaced DNA matches. Nineteen unplaced DNA matches were found who shared more than 100 cM with the two brothers. (2) The family trees of these unplaced DNA relatives were compared to each other, and common ancestors who recurred... (More)
- The present paper describes case studies where the purpose was to identify two unknown ancestors: the author’s paternal grandfather [FF] and his paternal grandmother’s maternal grandfather’s father [FMMFF]. A four-step method was used: (1) The author’s and his brother’s closest atDNA matches were identified, and the genealogical relationships to these matches were searched for by a comparison with their family trees. Those atDNA matches for which no explanatory genealogical relationship could be found were named unplaced DNA matches. Nineteen unplaced DNA matches were found who shared more than 100 cM with the two brothers. (2) The family trees of these unplaced DNA relatives were compared to each other, and common ancestors who recurred in the family trees of at least two unplaced DNA relatives were referred to as genealogical junctions. The four “strongest” genealogical junctions were focused (involving, eight, four, three, and three unplaced DNA matches, respectively). (3) An analysis of the connectedness between these genealogical junctions (e.g., marriages between descendants) were used to generate two hypotheses: the FF Norberg hypothesis, and the FMMFF Jon Pehrsson hypothesis. (4) The FF Norberg hypothesis was tested in collaboration with four descendants of the Norberg family who tested their atDNA, and one of them who also tested his Y-DNA, and the results fully supported the hypothesis. The FMMFF Jon Pehrsson hypothesis was tested by segment triangulation methods, to see if DNA segments shared with descendants of Jon Pehrsson’s (*1795) children overlapped with DNA segments shared with descendants of the author’s FMMF. Support for such DNA sharing was found on seventeen of the chromosomes, and the most conclusive support was found on chromosome 16. The results are discussed in terms of the distinction between proofs and evidence, the sensitivity of the genealogical junctions method, the importance of having one’s siblings DNA tested, the confounding factor of the number of descendants of a hypothesized ancestor, and the choice of cut-off for identifying the set of unplaced DNA matches. (Less)
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https://lup.lub.lu.se/record/0790ee20-d386-4058-8b34-6768cc07794e
- author
- Lundh, Lars-Gunnar LU
- organization
- publishing date
- 2023
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- unknown ancestors, atDNA, Y-DNA, segment triangulation, genealogical junctions
- in
- Journal of Genetic Genealogy
- volume
- 11
- issue
- 1
- article number
- 111.002
- pages
- 43 pages
- ISSN
- 1557-3796
- language
- English
- LU publication?
- yes
- id
- 0790ee20-d386-4058-8b34-6768cc07794e
- alternative location
- https://jogg.info/article/111-002/
- date added to LUP
- 2024-03-28 14:20:21
- date last changed
- 2025-04-04 15:29:47
@article{0790ee20-d386-4058-8b34-6768cc07794e,
abstract = {{The present paper describes case studies where the purpose was to identify two unknown ancestors: the author’s paternal grandfather [FF] and his paternal grandmother’s maternal grandfather’s father [FMMFF]. A four-step method was used: (1) The author’s and his brother’s closest atDNA matches were identified, and the genealogical relationships to these matches were searched for by a comparison with their family trees. Those atDNA matches for which no explanatory genealogical relationship could be found were named unplaced DNA matches. Nineteen unplaced DNA matches were found who shared more than 100 cM with the two brothers. (2) The family trees of these unplaced DNA relatives were compared to each other, and common ancestors who recurred in the family trees of at least two unplaced DNA relatives were referred to as genealogical junctions. The four “strongest” genealogical junctions were focused (involving, eight, four, three, and three unplaced DNA matches, respectively). (3) An analysis of the connectedness between these genealogical junctions (e.g., marriages between descendants) were used to generate two hypotheses: the FF Norberg hypothesis, and the FMMFF Jon Pehrsson hypothesis. (4) The FF Norberg hypothesis was tested in collaboration with four descendants of the Norberg family who tested their atDNA, and one of them who also tested his Y-DNA, and the results fully supported the hypothesis. The FMMFF Jon Pehrsson hypothesis was tested by segment triangulation methods, to see if DNA segments shared with descendants of Jon Pehrsson’s (*1795) children overlapped with DNA segments shared with descendants of the author’s FMMF. Support for such DNA sharing was found on seventeen of the chromosomes, and the most conclusive support was found on chromosome 16. The results are discussed in terms of the distinction between proofs and evidence, the sensitivity of the genealogical junctions method, the importance of having one’s siblings DNA tested, the confounding factor of the number of descendants of a hypothesized ancestor, and the choice of cut-off for identifying the set of unplaced DNA matches.}},
author = {{Lundh, Lars-Gunnar}},
issn = {{1557-3796}},
keywords = {{unknown ancestors; atDNA; Y-DNA; segment triangulation; genealogical junctions}},
language = {{eng}},
number = {{1}},
series = {{Journal of Genetic Genealogy}},
title = {{Case studies using genealogical junctions among unplaced DNA matches to identify unknown ancestors.}},
url = {{https://jogg.info/article/111-002/}},
volume = {{11}},
year = {{2023}},
}