ThruLines® is a tool from AncestryDNA that shows you how you might be related to people with whom you share DNA.
A ThruLine is a hypothetical connection based on information from your family tree that supports a link between your tree and the family tree of the person you match (a match is someone who shares some DNA with you).
For a ThruLine to exist both you and your match need to have a family tree linked to your DNA test. AncestryDNA uses the family tree linked to your test to find people who are in your tree and also in the trees of your matches.
You can find ThruLines from any page on Ancestry®. Click the DNA tab to start. ThruLines are available for ancestors through to 5th great-grandparents.
Here is a screenshot of my husband Greg’s ThruLines.
We know all of Greg’s great great grandparents, but when it comes to earlier generations there are gaps. ThruLines, using a combination of DNA and family trees, has the potential to help identify some of the ancestors whose name we don’t know. These suggestions are identified in green.
Thomas Harvey, born 1739, has been identified as possibly one of Greg’s fifth great grandfathers.
I select Thomas from the grid on ThruLines. While hovering it shows me there are two DNA matches who are also descended from Thomas. I am invited to evaluate the relationship paths.
One of the matches is a second cousin descended from Greg’s great grandmother Edith Caroline Edwards. The other match is identified as possibly a sixth cousin.
If I click on the green ‘Evaluate’ button beside the name of Thomas Harvey, I see two different sorts of trees to review. One tree is created by the DNA match, but it is a private tree with apparently no records. However, clicking on the private tree I can see that there are in fact 13 records attached. So I can evaluate the possible shared ancestry I have written to the match requesting access to the tree.
There are also 3 other trees with Thomas Harvey, with up to 3 records attached. The researchers have no DNA connection but are researching the same ancestors. Selecting one of the other trees I can see the three attached records and I can review these further. I am also invited to add Thomas to my tree on the basis of the research done by the Ancestry member. I prefer to progress more slowly and to evaluate the records to see if Thomas Harvey is indeed the father of Jane.
ThruLines has given me some hints to work on to go further back on the Harvey line and review the records to see if I can link Greg’s 4th great grandmother Jane Harvey to Thomas and Patience Harvey. The difficulty is that Harvey is not an uncommon surname and Jane is a common forename. It is hard to be certain that Jane Harvey is linked to this family. Parish records in the late eighteenth and early nineteenth centuries are less useful in making connections between the generations. I do not think there are wills available for this family which would help to link the generations.
ThruLines® is a useful tool for suggesting connections between DNA matches and providing hints about possible relationships. However, as with all such hints and clues, the written records must also be assessed to determine if the relationship suggested by the DNA evidence actually holds
AncestryDNA has launched a new feature, a chromosome painter, which ‘paints’ your DNA with your ethnicities, showing the DNA regions that make up your ethnicity estimate.
Overnight my kits updated to show the new information. It’s found under the ‘DNA Story’ tab.
To discover where you come from, we compare your DNA to the DNA of people with known origins from around the world. These people are our reference panel. Our reference panel has over 56,580 DNA samples from people with deep regional roots and documented family trees. We survey your DNA at over 700,000 locations and look at how much DNA you share with people from the reference panel in each ethnicity region.
Recently AncestryDNA provides estimates of ethnicity inheritance from each parent. They use your DNA matches to split your DNA into the halves that came from each parent. First, they find the segments that connect only to one parent or the other. Then, they separate out the DNA you got from each parent by piecing together the segments that overlap. After they have separated your DNA into the parts that correspond with each parent, they calculate an ethnicity estimate on the two halves. From this, they can show your “ethnicity inheritance”—the ethnicity percentages passed down to you from each parent.
These are my results.
Both of my parents have tested with AncestryDNA, so I can compare the estimate with its results. The differences are partly because I inherited only part of their DNA.
Column 1 has the ethnicity percentage I am estimated to have inherited from my parent and column 2 has their ethnicity estimate from their own test with AncestryDNA.
% I inherited from parent 1
My father’s ethnicity estimate
Scotland
41%
43%
Germanic Europe
0%
3%
England and Northwestern Europe
6%
8%
Sweden and Denmark
0%
0%
Wales
3%
14%
Ireland
0%
31%
Basque
1%
% I inherited from parent 2
My mother’s ethnicity estimate
Scotland
0%
2%
Germanic Europe
33%
79%
England and Northwestern Europe
7%
10%
Sweden and Denmark
6%
3%
Wales
0%
0%
Ireland
3%
0%
Eastern Europe and Russia
0%
6%
Baltics
1%
0%
It seems doubtful to me that I inherited Irish ethnicity from my mother. She herself shows no Irish ethnicity in her results and my documented family tree has an Irish connection on my father’s side, reflected in his ethnicity results, with no Irish connections for my mother.
AncestryDNA’s Chromosome Painter displays these results:
My Chromosome map at AncestryDNA as at July 2022
My chromosome map divided between my two parents
When I look at the results by different regions I see that Ireland has been assigned solely to chromosome 7, as has Wales. AncestryDNA has allocated Wales to one of my parents and Ireland to the other.
I suspect the breakdown by chromosome needs to be refined.
By way of comparison this is my father’s AncestryDNA chromosome painter picture. It can be compared with the map I have developed using DNAPainter.
My father’s Chromosome Painter results from AncestryDNA July 2022
My father’s chromosome map at DNAPainter where I have been able to assign shared DNA according to ancestors shared with DNA matches
For the most part AncestryDNA has allocated regions to whole chromosomes.
So far at DNAPainter I have only managed to paint just over a quarter of my father’s DNA profile. I can make some comparison between the two diagrams.
The Basque inheritance AncestryDNA shows on the paternal chromosome 1 appears to be inherited from Philip Chauncy and Susan Mitchell, my father’s great great grandparents.
My father has inherited Scottish and Irish ancestry from both his mother and his father. His Welsh ancestry was inherited only from his father. This does correspond with my known tree.
English ancestry has only been inherited from his mother; English ancestry is not so well defined for me – many forebears were born in England but had come from elsewhere, the issue becomes from what generation ethnicity is determined.
My father has inherited his Germanic Europe ancestry from his father on chromosome 6. It is not clear which ancestors might be responsible for this inheritance.
To be useful AncestryDNA’s Chromosome Painter diagrams clearly need more work.
I remain more interested in ancestral contributions to DNA rather than the vague attributions of ethnicity.
Unfortunately, for privacy reasons (or so it is said), AncestryDNA chooses not share detailed information about DNA matches. To obtain the details and be able to derive the information about which DNA you inherited from which ancestors you need to use other companies, such as MyHeritage, Family Tree DNA, or GedMatch.
AncestryDNA announces changes to its matching policy
From time to time users of the AncestryDNA service are confronted by a message advising that:
Our backend services are overtaxed at the moment and we are unable to retrieve all your matches. We apologize for the inconvenience, please try again later.
At other times users are told, “Something went wrong. Try reloading the page in your browser, or come back later.”
Refreshing the page often fails to work and users are forced to accept the invitation to ‘come back later’. Sometimes even the less specialised Ancestry.com site becomes overwhelmed.
AncestryDNA has more than 18 million samples in its database. It uses enormous computer power to store data and compare DNA. This is costly, of course, and where its methods produce false positives, inefficent.
Recently the company announced that it will no longer provide details of matches with only one segment where that segment is smaller than 8 centimorgans. The company gives as the reason for this new policy that
the shorter the length of the detected IBD segment (expressed in genetic distance), the less likely it is that the detected chromosome segment is truly inherited from a common ancestor.
AncestryDNA Matching White Paper Last updated July 15, 2020 – Discovering genetic matches across a massive, expanding genetic database
AncestryDNA notes that:
it has “…changed the [minimum] amount of DNA you need to share to be considered a match with another individual to 8 cM”.
from late August “…you’ll no longer see matches or be matched to people who share 7.9 cM or less DNA with you unless you’ve messaged them and/or included them in a note, or added them to a group (including your starred group).”
the change has been delayed “…until late August so you have time to review and determine if you want to save any very distant matches by sending them a message and/or including them in a note or group”.
Definitions, and what the AncestryDNA announcement means
A centimorgan (cM) is “a map unit used to express the distance between two gene loci on a chromosome. A spacing of one cM indicates a one percent chance that two genes will be separated by crossing over.”
The more centimorgans person A shares with person B the closer they are likely to be related. Your chromosomes have a total length of about 7400 cM, so you share about 3700 cM with each of your parents. Two people who share 6 to 7.9 cM are likely to be about 6th cousins, that is, they possibly share 5th great grandparents.
If you are related to a DNA match then the DNA segment or segments you share with at least one other person are identical by descent (IBD); you and your match inherited the segment from a common ancestor without recombination, and the segment has the same ancestral origin for you and your match.
The blogger Roberta Estes has estimated that 18% of her total matches share 7 cM and 30% share 6 cM. AncestryDNA’s purge of matches smaller than 8 cM will reduce her number of DNA matches by nearly half.
It has been estimated that about half the matches in the 6 to 7 centimorgan range are false positives. These matches do not truly demonstrate inheritance from a common ancestor. An error might have occurred when the DNA testing company compiled the chromosome marker: the DNA variations or the series of single nucleotide polymorphisms (SNPs) .
The companies’ matching algorithms do not treat the paternal and maternal chromosomes separately. Consequently consecutive SNP results for a short segment of DNA may appear to be half-identical in two individuals when in actuality the DNA sequences are not identical because the SNPs match on opposing chromosomes or because of errors in the matching algorithms. False matches can be the result of pseudosegments (matching alleles zig-zagging backwards and forwards between the maternal side and the paternal side), compound segments and fuzzy boundaries.
DNA is inherited so a match must also match one of our parents
If a person appears to match me but does not also match either of my parents, something has gone wrong in the matching process, for if neither of my parents shared the segment that appears to justify our match that person and I did not inherit the segment from a common ancestor.
The blogger Debbie Kennett found that 54% of her matches in the 6 to 7 cM range were not shared by either of her parents.
If about half of all DNA matches in the AncestryDNA database are very small and about half these are false positives, then about a quarter of the matches in our list of matches are false positives and are not genealogically relevant.
My experience
On 15 August 2020 I had 25,434 DNA matches to individuals. With 125 of these people I share 20 Cm or more. There are 25,309 distant matches with whom I share between 6 and 20 cM. Unfortunately there is no way using AncestryDNA to count matches in the range of 6 to 8 cM.
As both my parents have had their DNA analysed I am able to look at my very small matches to assess whether they match either of my parents.
Recently I looked at my small matches where AncestryDNA used its ‘Thrulines’ algorithm to show we both share common ancestors on our family tree and share DNA.
Fan chart showing the genetic ancestors identified by AncestryDNA using ThruLines for small matches 6 – 7 centimorgans (August 2020; Fan chart generated by DNA Painter)
I have 9 matches with shared common ancestors and shared DNA of 6 to 7cM. Of these matches 8 also share DNA with my father. The 9th match has a strong genealogical connection on my Mainwaring line and I do not doubt we are 5th cousins. However, he does not show up among my father’s DNA matches so despite being cousins we do not share DNA. It is estimated that only one third of fifth cousins share DNA.
It may be that the match with my father was somehow modified by AncestryDNA’s proprietary Timber algorithm, which tries to eliminate false matches “because they are of the same ethnicity or population — meaning that they (and many others from that same population) share DNA that they inherited from a distant ancestor who lived much longer ago”.
The Timber algorithm removes matches where the segments show “identical DNA with thousands of other people at that particular place”.
Recording notes about matches in the AncestryDNA database
AncestryDNA allows users to make personal notes in their database for each of their matches. Users can record when they messaged a match, how they believe they might be related, and the details of their shared match.
part of the list of AncestryDNA matches. Those in the list where AncestryDNA’s Thrulines algorithm have identified a common ancestor are shown with a green leaf in the 3rd column – see orange arrows. Part of the notes field appears in the 4th column see green arrows.One of my DNA matches showing my notes about the match
I looked at the 38 matches in the range of 6 to 7 cM shared DNA where I had made notes.
Of these 38 matches only one was shared with my mother, who shares 9 cM with that match. I don’t know how we connect.
Of 19 matches for which I had made notes and messaged, the matches also recorded shared DNA with my father. Three show common ancestors. Sixteen do not show common ancestors at present, although for several I know definitely how we are related.
Eighteen matches that I had annotated do not show as sharing DNA with either of my parents. It is thus likely that these matches and I do not share a common ancestor who can be genealogically traced.
Two of these matches had previously shown up as common ancestors, a green leaf in the list and the connection between our trees identified but no longer show up with the connection between our trees. Moreover they do not share DNA with my father.
For 2 of the 18 matches my father does not show as sharing DNA but does share DNA with another relative administered by the same manager. To me this indicates a possibility that the match is genuine but AncestryDNA’s Timber algorithm has modified my father’s match so it does not show up.
Consequences
I am not concerned if AncestryDNA removes smaller matches from my match list. Based on my very small review I accept that around half of the matches do not share DNA with my parents and thus are not useful matches for genealogy.
Of the remaining matches I already try to make connections with cousins who are researching the same ancestors using Ancestry.com’s member connect facility, which helps users to find fellow users researching the same ancestor. So while the ‘Thrulines’ method of highlighting shared DNA and common ancestors on a tree is useful, it is not the only means to make connections with cousins.
The Member Connect option is highlighted by the orange arrowWhen you click through to Member Connect you can see other people who are researching the same ancestor, the facts they have used and the Ancestry.com sources they have saved to their tree. Sometimes Ancestry.com does not correctly identify the common ancestor and you can ignore their suggestion.
Other matching services
Databases such as MyHeritage, FTDNA, and GEDMatch have tools that AncestryDNA does not provide. The tools are based on a chromosome browser, which helps to reveal details about the matched segment, enabling users to compare the shared segment with other matches. Without this it is impossible to be confident that the inherited segment is indeed from a distant ancestor. (See my post on Triangulating Matilda’s DNA.)
These other matching services have databases considerably smaller than that of AncestryDNA. Notwithstanding the better tools they have and the ability to see details of shared segments, I think it is best to test at AncestryDNA in the first instance because of the larger pool of matches.
Estimate of the size of the major autosomal databases in January 2020 caculated by Leah Larkin and published at https://thednageek.com/autosomal-dna-database-growth/ In January 2020 AncestryDNA announced it had past the 16 million mark; in July 2020 AncestryDNA announced it had passed 18 million tests. When we first tested in July 2016 the AncestryDNA database was less than one sixth the size.
Conclusion
The findings that a significant proportion of DNA matches are not genealogically significant seems plausible . For those small matches that are in fact genealogically sound I am prepared to miss out on these and concentrate my research efforts on the many thousands of larger DNA matches where I can be confident that there is definitely shared DNA and a genealogical connection if I could work it out – there are plenty of puzzles yet to be solved.
I will be pleased if AncestryDNA’s decision to remove small matches relieves pressure on its computing resources and improves response time for its users.
How will these proposed changes affect subscribers? I hope that AncestryDNA will provide more information about shared matches and new tools for exploring DNA data. And I wouldn’t mind at all if I never saw the “backend services are overtaxed” message ever again.
Sources
AncestryDNA Matching White Paper Last updated July 15, 2020 – Discovering genetic matches across a massive, expanding genetic database
We share more and longer segments of DNA with our closer cousins, a fact that can be turned to use in family history research: find someone with whom you share a significantly long string of DNA and that person is your genealogical relative – you can probably work out how you are related.
Cousinship in the great tree of life means a common ancestor: whales and cows are related in this way. The DNA we share, or to be precise, the fact that we share it, provides clues about our relative places in the tree. To focus in a little, our relative places in the tree of our direct forebears and cousins are indicated by the segments of DNA we share. The more DNA I share with someone the more recent our common ancestry.
Last year I wrote about AncestryDNA’s ‘ethnicity estimates’ and ‘genetic communities’. AncestryDNA has two ways of looking at your genetic background: the ethnicity estimate which compares your DNA to a reference group and genetic communities where you are linked with cousins who share DNA from a similar geographic area.
AncestryDNA’s ethnicity estimate is intended to be a measure of a person’s ethnic makeup. Are you partly Inuit? Were your ancestors Tasmanian Aboriginals or Scottish Highlanders? AncestryDNA calculates the estimate using DNA data about people who, it is said “…have long-standing, documented roots in a specific area”. This group of people identified by the company provide a reference group for ethnicity estimates.
Genetic communities, compiled on the basis of shared DNA, are defined as “groups of AncestryDNA members who are most likely connected because they share fairly recent ancestors who came from the same region or culture.”
It is said that a large proportion of people who pay to become members of Ancestry do so in order to discover their ethnic makeup, and presumably many of them are satisfied with what they are told. Ethnicity is a tricky concept, however, and Ancestry’s pitch about ‘long-standing’ (how long?), ‘documented’ (by whom? how?) roots in a specific area (how is the area specified?) sharing ‘fairly recent’ (how recent?) ancestors (which?) in a ‘region’ (of what extent?) or culture (what’s that, for Heaven’s sake?), is a pitch that will strike many people as promoting something largely meaningless. [AncestryDNA explains some of this in their 2019 Whitepaper on ethnicity estimates but you can see for example that they are estimating Aboriginal and Torres Strait Islander ethnicity on the basis of 14 DNA samples only.]
In late July 2020 AncestryDNA updated its genetic communities calculations, including those for communities associated with European and British settlers in Australia. I have looked again at my family’s place in the ethnicity estimates and genetic communities provided by AncestryDNA. The updated AncestryDNA genetic communities of my husband Greg and of my father became more specific: no longer vaguely “Southern Australia British Settlers” my father is now part of the group “South Australian European and British Settlers” genetic community and Greg is linked to the “Victoria, Australia, European and British Settlers” genetic community. Our ethnicity estimates have not been updated.
My father’s AncestryDNA ethnicity estimate showing the link to the South Australian European and British Settlers genetic communityGreg’s AncestryDNA ethnicity estimate showing the link to the Victoria, Australia, European and British Settlers genetic community
As I type these notes my cat Vinnie is sitting on my desk amusing himself by pressssssssssssssssssing randommmmmmmmm keys. I moved his paws, but now he’s taken to making sarcastic comments, and it’s hard to concentrate.
ME: “Most of Greg’s forebears came to the Colony of Victoria at the time of the gold-rushes and the assignment of this genetic community makes sense. AncestryDNA provides the information that just over 127,000 AncestryDNA members are part of this genetic community.”
VINNIE: “I’d say that the vast majority of his forebears didn’t come to Victoria at all. Most of them saw out their days on the African savannah. I’d call this a genetic community of approximately 50 million. What AncestryDNA ‘provides’ is just gas.”
Three close cousins have also been assigned to this community – we know how we are related to these cousins.A timeline with a potted history links forebears – for the most part the linking is accurate, these forebears are all associated with Victoria.
VINNIE: “In the logic trade that’s called a reductio ad absurdum. AncestryDNA’s methods make the daughter the mother of the mother.”
ME: “This was an anomalous result”.
VINNIE: “Did you get your subscription back?”
My mother’s DNA results summary report from AncestryDNA in October 2019
ME: “In response to this assignment of genetic communities and while waiting for the update, I removed my results from AncestryDNA by updating my settings and choosing not to see my matches and by not being listed as a match. My strategy seems to have worked. In the latest update my mother is no longer assigned to any Australian genetic community.”
VINNIE: “If I remove myself from the veterinarian’s appointment list I will no longer be assigned to it as a cat and you won’t have to take me for my annual checkup. Great.”
My mother still has very few DNA matches on AncestryDNA; the only match where I know how we are related is to me and I am also the only match sharing more than 50 centimorgans – that is all other of my mother’s DNA matches are likely to be no closer than 3rd cousins.my mother’s ethnicity estimate as at August 2020
ME: “Ethnicity estimates including the assignment by AncestryDNA to genetic communities need to be treated like any other hint with caution but as a clue to one’s origins”
VINNIE: “It was thought that the One Eyed One Horned Flying Purple People Eater had to be treated with caution too, but he turned out to be harmless. There weren’t any purple people for him to eat. You needn’t be cautious about nonsense.
Shortly before GeneticAffairs was asked to stop offering the AutoCluster analyses that employed Ancestry data, I ran Greg’s AncestryDNA matches through their autoclustering tool. AncestryDNA allows you to gather the same information, but I and many other users found the organisation and visual presentation offered by GeneticAffairs very useful.
I was looking at one of the smaller clusters – cluster 21 on the chart – and the associated notes, when I noticed that there was a small family tree of 22 people attached to one of the matches. Looking at the tree I noticed the Bell surname, which matched what I knew of the rest of the cluster. There was also a match with the Darby surname. Although I did not recognise Henrietta, the Darby surname did seem to fit the tree of the other shared matches where I did know how we are related, namely the trees of my Sullivan cousins.
small tree from Greg’s DNA match with a clue linking the match to the Darby family
I contacted Greg’s second cousin LB on Facebook to share the discovery, saying, “I have had a look at the tree [of SK]. She has a Bell marrying a Darby. Her tree has no details but I ran Vic BDM and found two births and the marriage.”
I dithered a little but decided to order the marriage certificate. The image of a Victorian historical certificate costs $20, not cheap, but there’s only so much you can do with just indexes.
1868 marriage James Bell and Henrietta Darby
It was indeed our family. At Creswick on 4 October 1868 Creswick James Bell, a miner, aged 22, married Henrietta Bell, no occupation, aged 24. Both were living at Creswick. They were married by a Wesleyan minister. The witnesses were Alexander and Agnes Pavina [I am not completely confident I am reading this correctly]. Henrietta said she was born in County Down, Ireland and her parents were John N Darby Compositor and Matilda Mograge.
I didn’t have Henrietta on our tree. If she was 24 in 1868 then she was born in about 1844.
I believe she is the child born in New Zealand, one of the two children of John Darby and his wife recorded on the shipping list of the Sir John Franklin, which left Auckland on 12 April 1845 and reached Hobart after what was described as ‘a tedious voyage of 25 days’. The other child was Matilda, who was baptised in Hobart in November 1845. She was born on 14 March 1845, less than a month before they set sail.
shipping list Sir John Franklin 12 April 1845
I had previously found no other record for the other child of John and Matilda Darby and had assumed it had died young.
I do not know why Henrieta said she was born in Ireland. Her parents were from Exeter, England and I am reasonably confident (if she recorded her age correctly) that she was born in New Zealand. Otherwise she was born in Australia. I ordered her death certificate which said she was born in Geelong and had lived all her life in Victoria. In 1896 her age was given as 47, which means she was born about 1849.
1896 death certificate Henrietta Bell
When John Darby married Catherine Murphy in Portland in 1855 he stated that his wife was dead and that he was the father of two children, one of whom had died. In fact, his wife Matilda was still alive and his second marriage was bigamous. I had assumed the living child was his daughter Matilda and that the unnamed child on the voyage had died. I now think that when John and Matilda Darby separated they kept a child each. Matilda junior stayed with her mother and Henrietta remained with her father, hence her knowledge of his name and occupation when she married. Her sister Matilda did not know her father’s name when she married William Sullivan in 1862.
Name John Darby Spouse Name Catherine Murphy Registration Place Victoria Registration Year 1855 Registration Number 2765
Henrietta and James Bell had five children before James’s untimely death in 1884:
Annie Jane Bell 1872–1918
Agnes Estella Bell 1875–1961
Catherine Elizabeth Bell 1878–1929
James Henry William Bell 1879–1928
Francis Sinclair Bell 1881–1935
Greg and his cousins share DNA with descendants of Annie and James Henry.
There were several Bell families in Creswick. The family trees I have looked at have different parents and a different death date for James Henry Bell, whose birth was registered as James William Bell. To confirm my suspicion that he was indeed related to Henrietta Darby I ordered his death certificate, and yes, James Henry Bell who in 1904 married Edith Jane Hocking (1884 – 1963) was indeed the son of James Bell and Henrietta nee Darby. I was thus able to resolve several more DNA matches that had puzzled me for some years. James Henry and Edith had seven children. He served in World War I, was wounded and was a prisoner of war.
1928 death certificate James Henry Bell
Yesterday we visited Creswick Cemetery and Long Point. Henrietta and James Bell’s grave is unmarked. Long Point, where they lived, is a pretty area of bushland next to a small settlement just outside Creswick.
Creswick Cemetery Methodist section row 13Long Point bushland reserve near Creswick
There are still unanswered questions about what became of John Narroway Darby and what Henrietta did before her marriage and how she came to be in Creswick.
I am pleased to have learned a little more about the family though. It’s fun to follow through the clues.
Last week I met one of my cousins, N., for the first time. He is interested in family history and, among other things, we talked about autosomal DNA testing.
A genealogical DNA test examines the nucleotides – the building blocks of DNA and RNA – at specific locations on a person’s DNA.
An autosomal DNA test looks at the 22 pairs of chromosomes that are not sex chromosomes (the X chromosome and the Y chromosome are sex chromosomes). These 22 chromosomes are known as autosomes. Autosomal DNA tests can be used to find cousins, and this often helps geneological research.
N.’s brother has already taken a test with AncestryDNA. We talked about whether it would it be better to take a test with another company and how much DNA might he and his brother share.
My recommendation is to test at AncestryDNA. N. and his brother will share close cousin matches but will also share different matches with more distant cousins.
AncestryDNA has by far the largest number of users. In May 2019 it had 15 million kits in its database.
The second largest database is 23andMe, with more than 10 million people in April 2019. It is an expensive test for Australians, however, as shipping costs are $40 US per kit. As a result there are fewer Australian participants. I have not tested with 23andMe.
FamilyTreeDNA (FTDNA) is one of the smaller databases. It is estimated to have about 1 million kits in its database. It is not marketed as aggressively as the other companies. However, with FTDNA, you can test not only autosomal DNA but also Y-DNA and maternal DNA, and so you are able to trace your direct paternal line and your direct maternal line further generations back. You can also transfer your DNA data from other
testing companies to join the database.
MyHeritage is a newer testing service. It allows people to transfer their DNA data into the MyHeritage database. In May 2019 it had about 3 million kits in May 2019.
Another service is GEDMatch. It is not a testing site but you can transfer your DNA data there and compare data and find matches with people who have tested at other companies. In May 2019 GEDMatch had about 1.2 million participants.
AncestryDNA does not allow users to transfer data into its database. To participate you have to test at its site.
Given this variety of testing and analysis services, I recommend testing at AncestryDNA and uploading your DNA data to FTDNA, MyHeritage and GEDMatch. A small fee at each of these separate sites can unlock some more advanced analysis tools.
If N. is interested in pursuing his paternal and maternal genealogy he would probably also be interested in testing at FamilyTreeDNA and taking their two additional tests for Y-DNA and Mitochondrial DNA.
Your siblings have inherited part of your parents’ DNA that you don’t carry. There is some overlap with your DNA. You would expect siblings to share about 50% of their DNA. In fact there is some variation. Siblings have been found to share 2209 to 3384 centimorgans of 6800 possible centimorgans, from 33% to just under 50%.
Schematic representation of the transmission of the autosomes of the grandparents to three siblings. Retrieved from Wikimedia Commons, diagram created by Jordi picart – Own work, licensed CC BY-SA 4.0
It has been estimated that up to 10% of third cousins and up to 50% of 4th cousins will not share enough DNA to show up as match. (Third cousins share great great grandparents and 4th cousins share 3rd great grandparents.)
Having your siblings’ DNA analysed will increase your chances of finding cousin matches. This will probably help you to make progress with your family history.
In 2016 I had my DNA analysed by AncestryDNA. In the three years since, all the genetic matches I have been able associate with known people are on my father’s side.
Recently I persuaded my mother to have her DNA analysed in the hope of learning more about my German forebears and to help connect with the relatives who sent my great grand parents the CARE package my mother remembers. (See Sweetened condensed care.)
My mother has few cousins and, it seems, German people in general are reluctant to offer up their DNA for testing. Apart from me, my mother has only 25 cousins who are estimated to be 4th to 6th cousin or closer, and her closest match on AncestryDNA shares 50 centimorgans of DNA (quite possibly a 6th cousin sharing 5th great grandparents). Her closest match on MyHeritage shares only 38 centimorgans. I have contacted several of these genetic cousins but I have not been able to establish our most common recent ancestor for any of them.
For the moment the only DNA match of my mother’s that I can associate with a known person is me.
AncestryDNA cannot recognise from the amount of DNA we share which of us is mother and which is daughter. It shows we share 3,405 centimorgans and that it is 100% confident that the relationship is that of parent and child.
Apart from telling you that you share DNA with cousins, AncestryDNA provides ethnicity estimates. I have always taken these with a grain of salt. They’re not meaningful. I last wrote about this in 2017 (Looking at my ethnicity as determined by DNA testing) where I noted an apparent underestimate of my German ethnicity. Then I had 100% European:
59% from Great Britain, which includes England, Scotland, Wales and
the Isle of Man
20% Europe East
12% from Ireland
4% from Finland / North-west Russia
2% from Europe-West
2% from Italy/Greece
<1% from the Iberian peninsula
Ancestry’s more recent estimate is this:
England, Wales & Northwestern Europe 65%
Germanic Europe 25%
Ireland & Scotland 10%
Additional Communities: Southern Australia British Settlers – From your regions: England, Wales & Northwestern Europe; Ireland & Scotland -> Adelaide, South Australia British Settlers
So I have dropped Italy and Spain, and I have a new grouping linking me to my Australian forebears.
On my father’s side, five of my great great grandparents were born in Australia. I have connected with cousins who are also descended from these great great grandparents. The grouping makes sense.
On my mother’s side of the family all eight of my great great grandparents were born in what is now Germany, five in Brandenburg, two in Baden-Württemberg and one in Schleswig-Holstein. Based on their occupations, surnames, and religion, I have no reason to believe their immediate ancestors were from other parts of Europe.
My mother’s ethnicity reported by AncestryDNA is
Germanic Europe 69%
England, Wales & Northwestern Europe 17%
Sweden 6%
Ireland & Scotland 2%
Norway 2%
France 2%
Eastern Europe & Russia 2%
The estimates looks credible as they are all European. However, AncestryDNA reports that my mother has “Additional Communities: Southern Australia British Settlers”!
My mother’s DNA results summary report from AncestryDNA in October 2019
AncestryDNA states about this community:
You, and all the members of this community, are linked through shared ancestors. You probably have family who lived in this area for years—and maybe still do.
…
The more specific places within this region where your family was likely from: Adelaide, South Australia British Settlers
It would seem that the Additional Communities derive from my DNA relationship with my mother. Since I belong to these communities from my father’s forebears, it appears that the DNA ethnicity estimates have been transferred by marriage! Not one of my mother’s DNA matches other than myself belongs to this community.
[When I attempted to explain this to him, my husband joked that it used to be said that after a while your wife seems to turn into her mother. AncestryDNA, however, has found a way of reversing the process. By counting half her husband’s DNA as her own, AncestryDNA is able to turn a woman’s mother into her daughter. The unfortunate husband, however, now finds that he’s copped his daughter for a mother-in-law, an arrangement no improvement over the earlier one]
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.
In his talk Essential Considerations for DNA Evidence, presented at RootsTech 2019, Blaine Bettinger, an American genetic genealogist claimed that “Without a report of tree completedness, it is nearly impossible to evaluate the use of DNA in a genealogical conclusion, even if it is soundly supported by documentary evidence!”
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.
Further reading
“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.
Anne's Family History 