Companies that offer genealogical DNA analysis usually provide tools to interpret the data, and you can use these tools to explore matches between you and people you share DNA with. If they appear on a public family tree you can try to connect to it from your own. If the tree is complete you will probably be able to find your most recent common ancestors.
You may also be able to find your more distant cousins by joining a project, a group of people working together to explore their common ancestry.
A Facebook group for researching shared Cornish ancestry
GEDMatch.com processes autosomal DNA data files from different testing companies to compare data derived from their DNA kits (‘autosomal’ means ‘concerning chromosomes that are not sex chromosomes’).
GEDMatch provides DNA analysis tools for genealogists, including tools for comparing your DNA test results with those of other people in the GEDMatch public database.
To use these tools you must first upload your DNA test results to GEDMatch. GEDMatch accepts results from the main testing databases at Ancestry.com, Family Tree DNA, MyHeritage, and 23 and Me.
A recent tool is Ancestor Projects. There are 38 projects presently registered WITH GEDMatch. Project members have DNA characteristics with whatever common trait or ancestry the project intends to explore. There are projects for royal pedigrees, deaf people, and connections from certain counties in Ireland.
GEDMatch home screen showing link to Ancestor Projects and also where to upload your family tree
I have joined the project for Cornish emigrants, which aims to identify DNA of emigrants from Cornwall. Greg has Cornish forebears. Members include people with GEDMatch kits who are descended from Cornish people who emigrated or from Cornish people who currently live in Cornwall. The new GEDMatch project tool allows the identification of matches and analysis of shared segments of DNA, with results limited to members within the group. The group shares information and communicates within a closed Facebook group.
So having joined the project what next?
If you are going to join a group I think it is a good idea to attach your family tree to your GEDMatch kit. You can upload your family tree to GEDMatch in the format of a GEDCom file which is a standard file type and which you can export from whichever program you currently keep your family tree in. You can create a link between a DNA kit and a person in your GEDcom. If you manage several DNA kits and they all relate to one family tree you can link the different kits to the right people on the family tree. The names and dates of living people are not shown when the tree is displayed in GEDMatch.
In the ‘Cornish Emigrants’ Facebook group we have a spreadsheet for sharing details. This shows who in the group is associated with which kit. It also lists the Cornish surnames in our family tree and details of our forebears who emigrated from Cornwall.
Surnames worksheet on Cornish Emigrants spreadsheet
One of the sheets from the Cornish Emigrants project shared spreadsheet
People in the group can run a report in GEDMatch to see which kits match their own and then begin a conversation to find connections.
An example of a report from the Cornish GEDMatch Ancestor Project
The group started at the beginning of August. It has already gained 119 users and 182 kits.
Not everybody in the GEDMatch group is connected to Facebook and the discussion there but most members are.
I hope that by connecting with this project’s group members I will be able to extend our family tree and learn more about our family history.
AncestryDNA has identified that Greg has Cornish DNA. Working on a GEDMatch project helps to find people with Cornish DNA and also an interest in following up on their family history from Cornwall.
My husband Greg’s great-great grandfather George Young (1826 – 1890) was from Liverpool. George probably arrived in Australia at the time of the gold discoveries in Victoria, perhaps lured by the chance of striking it rich, though it’s hard to be sure, for as yet I don’t know exactly when or why he emigrated, and I know nothing about his parents or his family.
This photo of George Young was passed to us by Noel Tunks of Maryborough
In any case, by 1853 George, following the rushes, was trying his luck on the goldfields. He met his wife-to-be Caroline Clarke on the Ovens diggings, near the border with New South Wales. Their first child was a boy, George, who was born and died as an infant at Beechworth in 1854. George and Caroline had twelve more children. Greg is descended from their oldest surviving child John Young (1856 – 1928).
Greg has had his DNA analysed by Ancestry.com. I have uploaded the results to Family Tree DNA, My Heritage, and GedMatch. His aunt B S has also tested her DNA. Through the DNA results we have connected with cousins descended from George Young and Caroline Clarke. This confirms the documentary evidence for the Young family in Australia, such as it is.
spreadsheet of DNA cousins who are descendants of George Young and Caroline Clarke and have tested at either AncestryDNA or MyHeritage
Greg and the cousins descended from George Young also share DNA with descendants of two men, James Young, born about 1838 in Liverpool, and Philip Young born about 1837 or a few years later in Liverpool.
We don’t yet know how George, James, and Philip are related.
From the amount of the DNA they share we know that B S and her second cousin P L (both great granddaughters of George Young) can be estimated to be about fourth cousins of A A, who is descended from James, and of H S F, who is descended from Philip. H S F and A A can be estimated from the DNA evidence to be about second cousins. Fourth cousins share third great grandparents and second cousins share great grandparents.
spreadsheet showing DNA matches with great grand daughters of George Young and descendants of John Young from Liverpool, plus some other matches that are related but we don’t yet know how.
H S F and A A are likely to share great grandparents, so it is possible that James Young born about 1838 and Philip Young born about 1840 were brothers.
If B S and P L are 4th cousins of H S F and A A, then it seems possible that George Young’s grandfather was also the grandfather of James and Philip Young. That is George was a first cousin of James and Philip.
I have traced the forebears of A A and I P. They are both grand daughters of Christopher Young (1875 – 1927), the son of Philip Young (born about 1837-1840, died 1910).
In 1862, when Philip Young married Mary Code (also spelt Coad) he gave his father’s name as John Young. [Liverpool Record Office; Liverpool, England; Liverpool Catholic Parish Registers; Reference Number: 282 NIC/2/2 retrieved through Ancestry.com]
I have traced the forebears of H S F. She is the daughter of Gerald Salter (1903 – 1986). Gerald was the son of Ellen Alice Young (1871 – 1962). She was the daughter of James Young born 1839, a seaman rigger. When James married Mary Martin in 1864 he stated he was a mariner living at Cropper Street Liverpool and his father was John Young, an engineer. [ Liverpool, England, Church of England Marriages and Banns, 1754-1932 Liverpool Record Office; Liverpool, England; Reference Number: 283-PET-3-67 retrieved through Ancestry.com]
Another researcher has suggested that James Young’s marriage record is in error and his father was in fact James Young, engineer/engine turner, who was born about 1810 in Dundee and died in 1859 (‘late of Monks Coppenhall in Cheshire’). James had a son named James who in 1859 was named as one of the executors in his estate. He was described in the will as an engine fitter of 46 Manchester Street Crewe in the Parish of Monks Coppenhall. [England & Wales, National Probate Calendar (Index of Wills and Administrations) 1860 for James Young retrieved through Ancestry.com]
I have traced the family of James Young 1810 – 1859. In 1861 some of the children were living with their widowed mother, Mary Young nee Harrison, at Manchester Street, Crewe in the Parish of Monks Coppenhall. James, then twenty-three and unmarried was an engine fitter living with his mother. [1861 census viewed through ancestry.com Class: RG 9; Piece: 2616; Folio: 74; Page: 24; GSU roll: 543000]
I have not yet found the death of Mary Young nee Harrison. She does not seem to be on the 1871 census. A possible death is Name: Mary Young Estimated birth year: abt 1813 Registration Year: 1869 Registration Quarter: Jan-Feb-Mar Age at Death: 56 Registration district: Nantwich Inferred County: Cheshire Volume: 8a Page: 224
It is possible that James Young, engine fitter, died before marrying and before the 1871 census. I cannot find him on the 1871 census in Crewe, Cheshire. A possible death of James Young engine fitter is : Name: James Young Estimated birth year: abt 1838 Registration Year: 1868 Registration Quarter: Jul-Aug-Sep Age at Death: 30 Registration district: Nantwich Inferred County: Cheshire Volume: 8a Page: 236 It seems unlikely that James Young engine fitter moved away from Crewe Cheshire and changed occupation to mariner, and it is also unlikely that his father’s name was wrongly recorded on the marriage document.
The family of James Young engineer does not include a Philip Young. The DNA evidence and the evidence of one Canadian shipping record supports the conclusion that James and Philip Young were probably brothers.
The Canada, Seafarers of the Atlantic Provinces, 1789-1935 records retrieved from ancestry.com have a James Young age 43 (born about 1845) on board the barque “Olive Mount” which departed Liverpool 19 March 1888 (discharged with mutual consent). He was discharged 12 March 1888 at Penarth Wales. He was not literate, he signed his name with an x. He was related to another crew member aboard. James was crew number 12 and his rank was able-bodied seaman. Also on board was Philip Young, crew number 11 – I believe this is James’s brother. Although the age is young, I suspect there was pressure for the men to understate their age so as to appear fit for the job.
It is my guess that James Young, forebear of H S F and also A O and P N is the son of a John Young engineer, not James Young (c 1811 – 1859).
Hypothesis: John Young is George Young’s uncle; John Young is father to Philip and James and George Young is their cousin -> A A and H S F are 3rd cousins. B S and P L 4th cousins to A A and H S F. As far as I know A O and P N have not tested their DNA.
Update: A O and P N have tested their DNA with AncestryDNA but neither shares DNA with Greg or his aunt B S. A O and P N are 1st cousins and share 1.104 centimorgans. P N shares 42 cM DNA with I P thus they are estimated 4th cousins. M F C, another descendant of Philip Young, also shares DNA with P N; they share 66 cM – also estimated 4th cousins. M F C shares a small amount of DNA with Greg but does not share DNA with Greg’s aunt B S.
Three years ago my husband Greg and I sent off our DNA for analysis. There were three family history puzzles I thought DNA techniques might solve. One concerned the parents of Greg’s great grandfather Henry Sullivan. Who were they? I didn’t know. I thought DNA data might help.
We knew Henry was brought up in an orphanage in Geelong, but its records told us only that he had been abandoned by his parents, nothing more. We could not find a likely birth certificate for him.
I revisited the problem, reviewing digitised newspapers at Trove and widening my date search slightly. I wrote up the results at `Poor little chap‘.
Henry was committed as a State Ward on 11 June 1866. He was said to be four years old. Both his parents were living but he had been deserted. Looking at the newspapers for the month before Henry was committed I found a report that mentioned a ‘‘little one’ who had been abandoned by a woman named Sullivan.’ The newspaper stated that ‘The decrepit and indiscreet creature walked off with the child clinging to her.’. Perhaps this child was our Henry.
Following through various newspaper reports I came to the view that this Henry was the child of William Sullivan (born 1839) and Matilda Frances Sullivan formerly Hughes (born 1845). Matilda Sullivan was the daughter of Matilda Priscilla Hughes nee Moggridge formerly Derby (1825 – 1868) and the step-daughter of David Hughes (1822 – 1895). Matilda Sullivan had another son, Eleazer Hughes (1861 – 1949). Eleazer Hughes had left descendants. I hoped that by matching Greg’s DNA with the descendants of Eleazer Hughes I might be able to confirm the hypothesis of Henry Sullivan’s parents.
Greg and his brother Dennis, his first cousins BS and MS, and his second cousin LB all share DNA with various descendants of Eleazer Hughes.
The challenge with DNA matching is to be confident about which of your forebears you have inherited the shared DNA from.
For close relations where you knew the test-takers beforehand and when the amount of shared DNA corresponds to the amount expected to be shared given the relationship, a shared DNA match is taken to be evidence of the relationship. If you have access to the shared chromosome details then you can attribute the shared ancestry to the shared DNA.
When the relationship is more distant you need to be confident that the DNA is shared from a particular ancestor and not from some other shared ancestor. That other ancestor may be on a part of the tree you or your match have not yet documented, that is, you do not know about your shared relationship. A measure of this is tree completeness -how many of your forebears have you documented for the necessary generations. If you are looking at an expected third cousin relationship then you expect to share great great grandparents. The question then becomes whether you and your match have both documented all sixteen of your great great grandparents. Only then can you be completely confident there is no another possible explanation of why you share DNA.
When it comes to fourth cousin relationships you are one more generation back. Both you and your match need to have documented thirty-two third great grandparents but also you need to take into consideration other possible relationships that might account for the amount of DNA that you share.
The distance between two gene loci on a chromosome is measured in centiMorgans (cM), defined as ‘the distance between chromosome positions for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01’, that is, how likely the segment is to recombine as it passes from parent to child.
If two sets of DNA are compared, a higher number of shared centiMorgans means greater confidence in the match, that is, greater confidence that the match represents a closer relationship.
Any given number of centiMorgans though can represent a variety of relationships. The Shared cM Project is a collaborative data collection and analysis project created as part of research into the ranges of shared centiMorgans associated with various known relationships. A tool called the ‘Shared cM Project 3.0 tool’ v4 allows users to compare the amount of DNA shared with a match with the accumulated results of the data collection of more than 25,000 relationships and their shared DNA. Using the tool is an aid to understanding what relationships are most likely to be represented by the amount of shared DNA.
Greg and L B are half third cousins to D J G. D J G’s great grandfather, Eleazer Hughes, was the half-brother of Greg and L B’s great grandfather Henry Sullivan. At MyHeritage Greg shares 89.2 centiMorgans across 4 segments with D J G. L B shares 64.1 centiMorgans with D J G. The amount of DNA shared between the cousins falls within the probabilities predicted using the shared cM tool.
Greg, L B and D J G share one triangulated segment on chromosome 10. The segment is 47.7 centiMorgans long.
I believe this DNA segment on chromosome 10 was inherited from Matilda by Greg, L B and D J G.
I checked that there was no other likely relationship to explain the DNA match by tracing the grandparents of DJG. Greg’s family tree and the tree of LB are both complete and documented up to their great great grandparents.
LB and Greg do have other matches with descendants of Eleazer Hughes but so far I have not been able to triangulate the DNA to a single segment. AncestryDNA, which has the most DNA matches, unfortunately lacks the tool, a chromosome browser, to demonstrate the triangulation.
Postscript: the poor little chap grew up, married and had a family. It seems he had a contended adult life. You can read about him at H is for Henry.
Florence Sullivan (nee Hickson), Elaine Sullivan, Anne Sullivan (nee Morley), and Henry Sullivan at “Navillus”, 7 Evelyn Street, East Bentleigh from the collection of a cousin and used with permission
AncestryDNA and MyHeritage have recently released new tools for showing how you might be related to your DNA cousins. Both companies look at your tree and the tree of your DNA cousin. If those trees do not connect, the company tentatively connects them using in addition other public trees in their databases.
Cousinships found in tentatively-connectly trees of course need to be verified. However, although you may seem to descend in the way suggested by the tentatively-connectly trees it is possible that you could be also descended from other ancestors not presently shown on the family trees. Confidence that the DNA match is from a particular couple increases with tree completeness. This confidence increases for both you and your match if your are able to establish that there are likely no other shared ancestors. Increased confidence that you are indeed related to the suggested DNA cousins comes from sharing common ancestors and simultaneously sharing DNA other cousins who also descend from the same common ancestors
One of these matches is me; another match is one of my second cousins, my father’s first cousin once removed. These relationships are well documented. We have met my father’s third cousin, R, and I also have confidence in the documentation of that match. However, we have not met H, my father’s 3rd cousin once removed. The relationship corresponds with my family history researches, and the shared 21 centimorgans of DNA fits within the range of a 3rd cousin once removed relationship as predicted by the shared centimorgan tool at DNAPainter.com.
Four matches descend from other children of Dominique and Susannah La Mothe.
These matches were all new to me. I had not previously corresponded with these cousins, nor was I aware that our trees had common ancestors. The shared DNA is small, but is greater than the 7 centimorgan small-match-limit usually suggested for genealogical significance. The number of shared centimorgans corresponds with the hypothetical relationships.
I decided to review cousin C who is predicted to descend from Frederick John Dominique Lamothe (1805 – 1864). I had not previously documented his descendants. The family tree attached to C’s DNA has only 27 people: she lists paternal grandparents and her mother, who died in 2015; there are no maternal grandparents listed. Thrulines incorrectly shows C’s grandfather’s information as common from her tree, but that does not correspond with the only public member tree attached to her profile, so perhaps C has a private but searchable tree on Ancestry.com.
I traced 13 children of Frederick John Lamothe, of whom five were daughters. His youngest daughter Ann Jane Lamothe (1857 – 1929) married William Galloway (1854 – 1909) on 5 August 1879 at Lezayre, Isle of Man. They had ten children. The second oldest was William Edward Galloway (1884 – 1967). That he was the father of Jean (1927 – 2015) is documented on a 1951 US Border-crossing document from Canada to the US. Her husband is also named in the document, further confirming the family relationship to C. I am satisfied with the genealogical links between C and Dominique Pierre and Susannah Lamothe based on baptism, marriage, death, and census records as well as the border-crossing record.
My father has eight matches at MyHeritage where MyHeritage has build speculative trees that may explain how Richard Rafe Champion de Crespigny and some of his DNA Matches are related. Of these I had already determined the connection for six and been in contact with the six cousins. The other two matches are his cousins, brother JJ and sister MJ, whose DNA kits are administered by Jo M, the daughter of JJ. My father shares 31.3 centimorgans of DNA with MJ and 8.3 centimorgans with JJ. The shared DNA figures are within the range appropriate for 5th cousins.
My Heritage demonstrates how the two trees combine and gives a level of confidence about the match, in this case 82%. While I did not have these cousins on my tree previously I have now added these descendants to my tree on the basis of birth, death, marriage, and census records.
MyHeritage provides a chromosome browser and lists segment details. I have painted these matches on to my father’s DNAPainter profile. The overlaps of the segments all correspond with forebears who descend from Dominique Pierre Lamothe and Susannah Corrin. To date 25% of my father’s DNA has been attributed to named forebears.
I last looked at tree completeness in May 2018 when I could name 45 of the possible 64 5th great grandparents I had. I did not split my result between my father’s family history and my mother’s but when I reviewed the statistics, it appeared that 44 of my possible 5th great grandparents that I know of are on my father’s side. That is, I know the names of 68% of my father’s fourth great grandparents, the generation that includes Dominique and Susannah LaMothe. I have improved my knowledge slightly. I now know 70% of my father’s 3rd great grandparents and 42% of my father’s 4th great grandparents, i.e. those forebears he would share as most common recent ancestors with fifth cousins. The overall tree completeness score at the 5th cousin level for my father is that we know 106 of a potential 127 individuals or 83%: 17% of the tree is unknown.
Chart showing the fourth great grandparents of Rafe de Crespigny. (Generated using MacFamilyTree)
In the case of the Thrulines match with C, her tree has only 27 people and could not be regarded as complete.
In the case of the MyHeritage tree maintained by Jo M and associated with the matches of MJ and JJ, the tree has only 84 people and is also incomplete. Jo M has trees on Ancestry.com but they show that Jo M has shown only 41 of the people associated with the trees of JJ and MJ up to the 4th great grandparent level, or 32%; thus her tree could be said to be 68% incomplete.
AncestryDNA’s Thrulines tool and MyHeritage’s Theory of Family Relativity tool are similar. Both tools have come up with matches at the fifth cousin level that seem plausible. In verifying the lines of descent and contacting the matches, I have discovered a little more about the descendants of my forebears. One cousin, Jo M, has shared pictures she took of our forebears’ graves on the Isle of Man. She has also traced the La Mothe family line further back than I have.
AncestryDNA has a new map feature currently in Beta mode and a group of AncestryDNA users is trying out the feature before it is launched.
I tried it by selecting one of Greg’s matches, SB, a person who is shown as being from Australia.
SB is an estimated 4th cousin DNA match sharing 22 centimorgans across 2 segments. I had messaged her twice a year ago when her match first came up but had no response. She has a small tree attached to her match showing two living parents and four deceased grandparents. Details for the grandparents showed:
Paternal grandfather: name but no middle names, death place Melbourne, Victoria, Australia, no birth or death dates
Paternal grandmother: name including middle name, death place Melbourne, Victoria, Australia, birth year 1927, no death date
Maternal grandfather: name but no middle names, birth and death place Sunshine, Victoria, Australia, birth and death dates 28 July 1915 and 12 November 1979
Maternal grandmother: name but no middle names, birth place Maryborough, Victoria, Australia and death place Melbourne, Victoria, Australia, birth year 1924 and death date 1 August 2005.
SB shares DNA with Greg’s 2nd cousin HS. It would seem on the basis of this connection that the most common recent ancestors will be on Greg and HS’s Dawson or Edwards line. HS and Greg share great grandparents Henry Dawson (1864 – 1929) and Edith Caroline Dawson nee Edwards (1871 – 1946).
Using the Victorian birth, death and marriage indexes, I developed a private non-indexed tree based on the data I had for SB. I started with the maternal grandparents. But I did not seem to be coming across familiar surnames and was quickly reaching back to the UK and areas that did not match those where Greg’s forebears came from.
I next looked at the paternal grandparents. I was having trouble finding their marriage and identifying the death of the paternal grandfather. However I successfully found the death date of the paternal grandmother from a death notice on the Ryerson index, a free index to death notices appearing in Australian newspapers. (The death notice is recent and can be viewed online.) Using the deceased search facility for the Greater Metropolitan Cemeteries Trust, I was able to find the burial site of the paternal grandmother and confirm the death details of the paternal grandfather, who had been buried in the same plot. From there I was able to trace the paternal grandfather’s pedigree using the birth, death and marriage indexes. It was reasonably quick and trouble-free. Within 3 generations I had a surname I recognised.
index record from the registry of Births Deaths and Marriages Victoria
Charlotte Victoria Edwards (1834 -1924), born St Erth, Cornwall, United Kingdom, and died Warrnambool, Victoria, Australia, was already on my main family tree although I did not know she had come to Australia and did not have her marriage or death details. Charlotte is Greg’s 1st cousin 4 times removed and SB’s 3rd great grandmother. Greg and SB are 5th cousins once removed. Their most common recent ancestors are Greg’s fourth great grandparents John Edwards and Jane Edwards nee Gilbert.
Charlotte was the daughter of Greg’s fourth great uncle James Edwards (1805 – 1883), and the granddaughter of Greg’s fourth great grandparents John Edwards and Jane Edwards nee Gilbert. James Edwards married Mary Nicholas and they had at least six children of whom Charlotte was the third oldest.
Charlotte and her family arrived in Portland, Victoria on 30 January 1855 on the Oithona, which had left Southampton on 16 October 1854. There were 344 immigrants on board. James Edwards was a 50 year old agricultural labourer from Cornwall. He was accompanied by his 47 year-old wife Mary and two children, Elizabeth aged 9 and John aged 4. Their religious denomination was stated to be Church of England and James and Mary, but not their two children, could read and write. The disposal register listing their disembarkation intentions noted he was “on own account” and address Portland. Three older daughters, Mary (Mary Ann), Jane and Charlotte were enumerated separately as they were then 23, 22 and 19. All girls were said to be Church of England and they could all read and write. The register stated that Mary went to Mrs Nicholson of Portland, Jane went to Thomas Must of Portland and Charlotte went with her father. One sun was enumerated separately. James was 17. He was described as an agricultural labourer from Cornwall, his religious denomination was Church of England and he could read and write. The disposal register noted he was “on own account” and address Portland.
Passenger list from the “Oithona” showing James, Mary, Jane and Charlotte Edwards as single passengers. Image retrieved from ancestry.com from database held by Public Records Office Victoria.Register of Assisted Immigrants from the United Kingdom. Microfiche VPRS 14.
Also on the Oithona was Charlotte Thomas nee Edwards (1811 – 1887) and her husband William Thomas, a mason. Charlotte Thomas was the sister of James and Thomas Edwards.
James’s brother Thomas Edwards (1794 – 1871) had arrived in Victoria in 1849. I assume James Edwards and Charlotte Thomas and their families came out as their brother Thomas recommended immigration to them. I do not know however if they met up in Victoria.
My father has a second cousin once removed, ‘GH’. I am GH’s 2nd cousin twice removed.
GH’s daughter administers his DNA kits. She asked me an interesting question. On the DNA evidence, is this the same person:
Ancestry – AnneYoungAU on Ancestry (shares 33 cM with my father)
Family Tree DNA – Christine Anne Young (shares 93 cM with my father)
GEDmatch – Anne Young A947648 (shares 63.5 cM with my father)
My Heritage – Anne Young (shares 56.3 cM with my father)
If they are the same person, how can the results be so different?
Also, on the DNA evidence, are these the same person:
Ancestry – RRC001 (shares 110 cM with my father)
Family Tree DNA – R. Rafe Champion De Crespigny (shares 134 cM with my father)
GEDmatch – RD A587626 (shares 113 cM with my father)
My Heritage – Richard Rafe Champion De Crespigny (shares 98.3 cM with my father)
DNA aside, of course, we know that they are the same two people. The first is me, the second is my father.
The reason that the amount of shared DNA seems to vary so widely has to do with different assumptions and techniques used to calculate genealogically significant DNA. As a species we share DNA with other forms of life, but much of this is irrelevant genealogically. Discarding the parts we share as living beings and concentrating on what we share as family relatives introduces different emphases. The result is apparent differences between DNA analysis by different companies.
AncestryDNA explains it in these terms:
“If you choose to upload your AncestryDNA raw DNA results to another website, they will look different for a number of reasons. Other companies do not use the same algorithms, database or methods to translate the data. Only AncestryDNA has access to the unique information available on Ancestry, including the family trees and records to help power the accuracy of the results. In addition, the proprietary algorithms that we use to calculate results are based on documented family trees and a one-of-a-kind, comprehensive database of DNA samples from around the world.”
Curious about the detail, I used DNAPainter, an online chromosome mapping tool, to investigate a little further.
I was interested to see the variation in what segments my father and I shared with GH so I painted the matches from MyHeritage, FamilyTreeDNA and GedMatch at DNAPainter using the default parameter excluding segments under 7 centimorgans and also experimenting with including all segments greater than 1 centimorgan (the lowest threshold allowed).
Reviewing the data for segments of 7 centimorgans or more I found that MyHeritage did not include matching segments on chromosome 1. The segment matched with GH corresponds to a known pile up area and is indicated with grey shading on the DNAPainter diagram. It probably indicates shared DNA without genealogical significance.
DNA profile comparing matches for GH with Rafe and Anne: 7 centimorgan threshold
Reviewing the data for all segments greater than 1 centimorgan I found that Family Tree DNA and GedMatch included these segments whereas MyHeritage did not. I shared some small segments with GH but my father did not indicating that I did not inherit these segments from the most common recent ancestor GH, my father and I share. In general 7 centimorgans is considered necessary before a segment is possibly inherited from a common ancestor.
DNA profile comparing matches for GH with Rafe and Anne: 1 centimorgan threshold
The MyHeritage estimates of shared DNA make sense in view of the 7 centimorgan threshold and by not including the shared DNA at the pileup region on chromosome 1. Unfortunately because the detail of the match at AncestryDNA is not revealed by that company I cannot comment on what data they chose to include or exclude for their match.
All this is a reminder that DNA matching, though a technique of great precision, makes certain assumptions, and operates within recognised limits. Its apparent accuracy will occasionally seem to vary. Be careful how you interpret DNA results. You are indeed related to the fly you just swatted- you murdered a distant cousin – and you are related to yourself, since your DNA, though analysed differently by different companies is all yours. Somewhere between you and blowflies are your cousins and other family members, not all of whom you’d want to claim for immediate relatives.
“International Society of Genetic Genealogy Wiki ISOGG Wiki.” Identical by Descent, International Society of Genetic Genealogy, 23 Nov. 2018, isogg.org/wiki/Identical_by_descent.
For a couple of days I have been experimenting with new DNA-analysis tools from GeneticAffairs.com developed by Evert-Jan Blom, a Dutch genetic genealogist.
The GeneticAffairs.com website automates the retrieval of new genetic matches from AncestryDNA, FamilyTreeDNA, and 23andme.
For each AncestryDNA profile I registered I was sent a spreadsheet with details of the match and notes I had taken. GeneticAffairs’s return email came promptly.
Privatised screenshot of part of a report received from GeneticAffairs showing summary information including notes I have made for genetic matches.
GeneticAffairs also offers a match-clustering report, clusters of shared
matches and group shared matches according to likely branches of the family.
My first report was for my husband’s Greg’s matches, using the default settings.
Auto cluster report with names of shared matches privatised
The centimorgan thresholds did not provide enough matches for a useful analysis. I could identify most of the surname groupings.
I then tried a report for my father’s matches, increasing the thresholds significantly.
This produced too many clusters, many of them quite small. For the three largest clusters they produced relatively small matches at the 4th cousin level. I do not know how we are related to any of the matches in these large clusters.
Changing the thresholds for the analysis of Greg’s matches produced more meaningful clusters.
2nd auto cluster report generated for Greg’s AncestryDNA genetic matches with revised centimorgan thresholds of 1200 cM and 30 cM
As well as the main clusters, additional genetic matches in the columns highlighted with the green and orange arrows give clues about other clusters. For example, those additional genetic matches indicated with the orange arrow give clues about the identity of the most common recent ancestors for the matches in cluster 11. In fact I have confirmed the three matches in cluster 11 descend from our Way forebears.
The second report for my father using revised centimorgan thresholds of 1200 cM and 30 cM produced more meaningful clusters also.
GeneticAffairs has very generous free credits. You can try their reports before paying for a subscription.
My husband Greg and I have had our DNA tested. We used ancestry.com. The tools that ancestry.com employs to compare details of family trees and shared DNA matches to help establish how we are related to others who have also tested at ancestry.com are quite useful but could be better. However, ancestry.com does not provide a chromosome browser.
A chromosome browser produces a diagram of where on your chromosomes you share DNA with your match. If you know how you and your match are related, you can deduce that you have both inherited that shared DNA from your shared ancestors. You can then attribute that shared DNA to those ancestors. When you don’t know how you are related, you can look at where you match and based on your analysis of who you inherited that bit of DNA from, you can predict how you are related. Ancestry.com in effect does this calculation for you with their shared matches tool but ancestry.com doesn’t show the calculations in making its predictions.
The tools offered by MyHeritage.com, GedMatch and Family Tree DNA include a chromosome browser which ancestry.com does not provide. A chromosome browser gives you the detail of what DNA you and your cousin share.
MyHeritage chromosome browser showing where Greg and one of his second cousins share DNA
So far with matches from MyHeritage, GedMatch, and FTDNA, Greg has been able to attribute 27% of his DNA to particular ancestors. The tool DNAPainter graphs attributed DNA based on matches with multiple cousins.
One of the genealogical puzzles I sought to solve with DNA was the parentage of Greg’s great grandfather Henry Sullivan. I produced a hypothesis that he was the son of Matilda Sullivan nee Hughes. I need more data on how various cousins share DNA to show that Matilda Sullivan nee Hughes was indeed the mother of Henry Sullivan. The shared matches tool of ancestry.com is incapable of showing that descendants of Eleazar Hughes, Matilda’s first son are definitely connected to descendants of Henry Sullivan. A chromosome browser would help to show that these cousins do indeed share inherited DNA.
To download DNA data from ancestry.com, choose the settings link on the top right hand corner of the AncestryDNA home page. On the right hand side you are given the option to download your raw DNA data. The steps are:
1. From the AncestryDNA status page click the link ‘manage test settings’.
2. On the ‘manage test settings’ page click the ‘Get started’ button on the right under ‘Download your raw DNA data’.
3. Enter your password. This will trigger an email that will be sent to your email account on file, which will include a link to confirm download of the DNA data.
4. Open the email and click the ‘Confirm data download’ button in the email.
5. On this download page click the button “Download Raw DNA Data”.
6. The file will then download to your computer.
Two years ago I sent off a sample of my DNA for testing. When I first received the results, I was unable to make any connection between my tree and the trees of people with whom I shared DNA.
I have made some progress since, however, speeded up by more testing: I persuaded my father to have his DNA analysed by Ancestry.com. His results are interesting and will be very useful to my family history research.
He, of course, is one generation closer than I am to the ancestors revealed by DNA matches. The difference in the numbers of matches, however, is greater than I expected.
My father has 219 matches estimated to be 4th cousins or closer. Estimates of how closely a person is related to someone is based on how much DNA they share. I have only 74 matches where I am estimated to be a 4th cousin or closer. I share 56 of these matches – 76% – with my father. (AncestryDNA provides a tool to filter matches shared with your father.)
I am not surprised that the great majority of my matches are on my paternal side, for my mother’s family is from Germany, where DNA testing in family history research is comparatively uncommon.
My father has 546 pages of matches on AncestryDNA. I have 305 pages. He shares DNA with about 27,275 people on the AncestryDNA database. I share DNA with about 15,225. Assuming that the overall ratio of paternal to maternal matches is proportionally similar to matches for 4th cousins and closer, about 11,500 of my matches are paternal. This means that my father has more than twice as many matches as I have with people who descend from the same forebears.
No matter how children’s segments of DNA are divided when they are inherited, their parents have larger and more complete segments, and as a result have more matches, of better quality.
AncestryDNA identifies people with whom you share DNA and whose family trees include the same forebears. It may be that you and your match have inherited the matching DNA from these forebears. AncestryDNA calls these shared ancestor hints. I have twelve shared ancestor hints on AncestryDNA. All these are paternal. One of these hints is with my father. Of the other 11, two are not in common with my father. The tree matches are paternal but my father is not shown as having the same DNA.
Family tree (Sun Chart generated through MyHeritage) showing the most recent common ancestors of shared DNA matches with Rafe and Anne (red text), with Rafe only (green text), and with Anne only (blue text).
Looking more closely at these matches I have but my father does not, I see that I share with one of these matches 6.1 centimorgans of DNA across one segment and with the other match I share 6.3 centimorgans across one segment. For one cousin we share 6th great grandparents and are 5th cousins once removed. The other cousin we share 4th great grandparents and are 5th cousins. Sharing 6 centimorgans is a very small amount of shared DNA. A centimorgan is a unit used to express the distance between two gene loci on a chromosome and it measures how likely the segment is to recombine as it passes from parent to child. I higher number of shared centimorgans means greater confidence in the match.
It is possible that I share DNA on my mother’s side with these two cousins and have the same people as ancestors on my father’s side, but the more likely explanation is that the AncestryDNA algorithms may have truncated the segments: these are in fact paternal segments. Examining the data for these two matches through GedMatch, FTDNA or MyHeritage could help provide some answers. These other three sites provide better information on where a person and a probable match share DNA.
My father has 22 shared ancestor hints: one hint with me, 9 shared with me and 12 hints where he has DNA matches with cousins and I do not. There are 12 cousins who have researched their family tree to the extent that they and I have identified shared ancestors. They are shown to share DNA with my father but they do not share DNA with me.
One of these shared matches is a third cousin once removed on the Chauncy line (my 4th cousin). My father and this cousin share 20.8 centimorgans shared across 3 DNA segments. AncestryDNA suggests I have no shared DNA: this match disappeared in one generation.
(This cousin’s tree has only 11 people in it. We are lucky to have a shared ancestor hint.)
I have corresponded with several of my father’s matches. The smallest match with a shared ancestor hint has 6.4 centimorgans across 1 segment. She and my father are 5th cousins once removed. She grew up in the village of Caithness, Scotland, where our mutual forebears lived. Her father still lives there. She has researched further back on that line, and I look forward to learning more about these of my forebears from her.
Unfortunately, very few of my father’s matches with hints have uploaded their DNA elsewhere, and this limits our ability to make new discoveries. Uploading the DNA data from ancestry.com to these other sites (GedMatch, MyHeritage, Family Tree DNA) is free and is not hard to do.
One of the nice things one can do with the information one gets from these other sites and not through ancestry.com, is you can attribute segments of your DNA to particular matches. For this attribution you need information about your shared ancestors and the numerical information provided by the testing company for each match so you can visualise it on your chromosomes. The application is called DNA Painter (https://dnapainter.com )
Only a few matches have uploaded their data or tested with sites that have details of how the DNA is shared. I have managed to paint, ie attribute inherited DNA to particular ancestors, for just under 10% of my father’s DNA so far using DNA painter.
Despite the limited data provided by ancestry.com, there is still much more analysis for me to do within the AncestryDNA database.
1) Who is your MRUA – your Most Recent Unknown Ancestor? This is the person with the lowest number in your Pedigree Chart or Ahnentafel List that you have not identified a last name for, or a first name if you know a surname but not a first name.
2) Have you looked at your research files for this unknown person recently? Why don’t you scan it again just to see if there’s something you have missed?
3) What online or offline resources might you search that might help identify your MRUA?
The starting point for my ahnentafel list is my children, the list formed by combining my tree with that of my husband Greg.
I know all the names of our children’s 3rd great grandparents.
In the next generation, however, I don’t know the parents of George Young (c.1826-1890), Greg’s great great grandfather. George is number 32 on the index; I don’t know the names of his parents, numbers 64 and 65.
There’s no help from his death certificate; the informant does not name his parents. Other information about him is scanty. From his death certificate I know that he was born in Liverpool, and this corresponds with details that he provided on the birth certificates of his children, but I have not found his marriage certificate. The reason may be that he and his wife Caroline Clarke were married before compulsory civil registration was introduced in Victoria in 1855, or perhaps they never formally married. I have not found a shipping record for him, and I have no evidence that he had any near relations in Australia. Land records, and I have several that concern him, give no relevant information. George did not leave a will. Frustratingly, the name Young is too common to identify George from the many other births in Liverpool about the same time or from people with the same name listed on the United Kingdom 1841 census.
I feel my best hope in identifying George’s parents and finding out more about his life before he emigrated to Australia is through DNA. Several of Greg’s cousins descended from George have tested their DNA. I hope that DNA will lead me to one or more of the descendants of George Young’s siblings. Their research might get me past the dead end I have come to with George himself.
Greg has a number of shared DNA matches (shown in green on the chart). I have not yet identified anybody descending from a brother or sister of George Young.
I do have some DNA matches from people with the surname Young who were born in Liverpool, descendants of Philip Young (1840-1910). I have not yet found the parents and grandparents of Philip to allow me to make the connection between our two trees, although we have several DNA matches. However, having an additional line to search, which appears to be connected by name, place and shared DNA, gives me a better chance of finding the family of George Young.