Combining archival, oral and DNA evidence to re-create family
Galway Genetic Genealogy Conference
12:10 p.m. Saturday 5 May 2018
Holy Rosary College, Mountbellew, County Galway
YouTube version (37:55):
Family history flows down through the generations via three
Talk to your known relatives and correspond with your closest DNA
matches. Sometimes the gaps left by one individual's
sources can be filled by those of a known or unknown relative.
- Most genealogists start by writing down the oral traditions
passed down through the generations to older family members.
- Archival sources, offline and online, are then
by genealogists to fill some of the gaps in the oral family
- DNA evidence now fills many of the remaining gaps left by
the traditional sources.
The boundaries between oral and archival can be blurred:
Stanford historian Richard White wrote in his family
Ahanagran: Storytelling in a Family's Past (Cork
University Press, 1999, p. 4):
- Is the description of the deceased on a death certificate
oral or archival? (Estimated age at death, parents' names, mother's
maiden surname, etc.)
- Are family letters and diaries oral or archival?
- Are published or unpublished family histories oral or
I once thought of my mother's stories as history. I
memory was history. Then I became a historian, and after many years I
have come to realize that only careless historians confuse memory and
history. History is the enemy of memory. The two stalk each other
across the fields of the past, claiming the same terrain. History
forges weapons from what memory has forgotten or suppressed. Few
non-historians realize how many scraps a life leaves. These
do not necessarily form a story in and of themselves, but they are
always calling stories into doubt, always challenging memories, always
trailing off into forgotten places.
The emergence of genetic genealogy has turned this two-way struggle
between memory and history into a three-way battle. All three types of sources must be consulted. None can be ignored.
- Does each source verify the others?
- Better still, does a new source fill gaps in the others?
- Or are there conflicts of evidence?
The genealogist has to be judge and jury.
- the Killeen family in 1911
- Patrick's greatgrandson and his brother Christopher's
granddaughter share 102.3 centiMorgans (GEDmatch) or 124 centiMorgans
(FamilyTreeDNA) of autosomal DNA
- this is consistent with the distribution of shared centiMorgans
for second cousins once removed
- Christopher's first marriage in 1934
- Christopher's second marriage in 1941
- not the parent expected (NPE)
- what birth or baptism record did Christopher produce before
- the Kellien family in 1901
- who was the one-month-old "nephew"?
- still a mystery
- "nephew" is the English translation of the Irish "garmhac"
- see Clare Past Forum discussion
- garmhac is the Irish word for a younger male relative who
expected to share a quarter of one's autosomal DNA - see DNA Detectives Autosomal Statistics Chart
NPEs can be revealed by oral, archival or genetic sources,
by the latter.
To re-create your family history as effectively as possible, you and
your DNA matches must use the various DNA websites to share the
relevant oral, archival AND genetic information with each other.
Where does our DNA come from?
- When a sperm fertilises an egg, each brings DNA, which is
replicated in every cell of the resulting person.
|22 paternal autosomes
|22 maternal autosomes
is short for autosomal chromosome.
- Y chromosome
- Only males have a Y chromosome.
The Y chromosome comes down the patrilineal line - from father,
father's father, father's father's father, etc.
This is the same inheritance path as followed by surnames, grants of
arms, peerages, etc.
- X chromosome
- Males have one X chromosome, females have two.
X DNA may come through any ancestral line that does not contain two
Blaine Bettinger's nice
colour-coded blank fan-style pedigree
charts show the
ancestors from whom men and women can potentially inherit
- Exactly 50% of autosomal DNA comes from the father and
exactly 50% comes from the mother.
Due to recombination, on
average 25% comes from each
grandparent, on average
12.5% comes from each greatgrandparent, and so
Siblings each inherit 50% of their parents'
autosomal DNA, but not the same 50% (except for identical twins).
- Everyone has mitochondrial DNA.
- Mitochondrial DNA comes down the matrilineal line - from
mother, mother's mother, mother's mother's mother, etc.
The surname typically changes with every generation in this line.
- This talk will concentrate on autosomal DNA.
DNA is also widely used for one name studies or surname projects.
- Targeted mitochondrial DNA comparisons can be
used to address
problems - e.g. did two women have the same mother? or just come from
the same female line?
- Targeted X DNA comparisons can also be
used to solve
problems - e.g. did two men have the same mother?
The Autosomal DNA and Genetic Genealogy Websites
You must link your DNA
match list and
your pedigree chart
and share them on the major autosomal DNA comparison websites:
MyHeritage.com only got its matching algorithm working properly in late
2017, so that Jim Palmer was not sure whether
the match which helped to identify his birth mother was genuine.
23andMe.com can not currently be recommended for genealogy for
- it essentially withdrew from the market by showing many, if
not all, of its
customers the message "We are continuing to modify some aspects of DNA
Relatives in preparation for the transition to the new 23andMe
October 2015 until at least May 2017;
- it withdrew further from the established market in August
becoming the first of the large companies to switch
to a GSA chip which is not compatible with the current
- it appears to have stopped hosting any type of family trees
for its DNA customers.
Before you get
your DNA results ...
- As soon as you have sent off your DNA sample, prepare
to combine your pedigree chart with your DNA results.
- Beginners may not be familiar with the term pedigree
chart, let alone GEDCOM
- Examples of pedigree charts: from TNG, Ancestral Quest, AncestryDNA, ancestry.com, FamilyTreeDNA
- You must use
your favourite genealogy software (e.g. Ancestral
Quest) to record your ancestors and cousins and
prepare your pedigree chart.
- Register at GEDmatch.com.
- Export a GEDCOM file containing at least the ancestors
of each DNA subject for upload to the relevant DNA websites
FamilyTreeDNA, GEDmatch, MyHeritage).
FamilyTreeDNA.com, include in the GEDCOM file any third cousins or
closer already at FTDNA and the shared ancestors; FTDNA will use this
information to assign other matches to the DNA subject's paternal and
maternal sides (example).
Identity v. Anonymity
- There is a trade-off between:
- increasing your chances of finding
long-lost cousins and ancestors (and being found by long-lost cousins);
- maintaining the privacy of your family history research
and DNA results.
- If you keep your DNA
results or known family tree private, then nobody will be able to find
you and you will not
be able to find any DNA matches.
- If you want to be found, then you must
let your potential cousins see your DNA results and your known family
- Some customers of the DNA companies appear to wish to
certain degree of privacy and anonymity
- Others find it paradoxical that
those trying to identify their anonymous ancestors can be so concerned
about anonymising their own identity.
- Do you want your descendants cursing you in perpetuity for trying to hide from them?
- If there was a mass murderer in your extended family, would
you object to your DNA being used to take him off the streets?
- DNA has let the genie
out of the bottle as regards secret adoptions and fosterings.
- If you want to keep family secrets secret, then keep your own DNA
and the DNA of all of your relatives out of the online databases.
The Basic Rules
- Reveal your birth surname:
- Most people inherit DNA with
their birth surname, so identify yourself as a minimum by
your birth surname with an initial or a title, e.g., P Waldron or Mr
Waldron or Miss Durkan.
- Reveal the gender of the person who provided the DNA sample:
- Valuable additional
inferences can potentially be drawn once it is known whether two X
chromosomes (female) or one X chromosome and one Y chromosome (male)
are potentially available for comparison.
Women do not have Y-DNA and are encouraged to
recruit their male relatives to provide Y-DNA, but they must NOT attach
female name to a male DNA sample, as this causes untold confusion.
Be especially careful not to inadvertently link a male's Y-DNA results
with a female's autosomal DNA results at FamilyTreeDNA.com, where
error-checking does not look for this.
- Avoid providing irrelevant information:
- Your first name, married
surname or marital status reveal nothing about your DNA, so you may
keep these private if you wish.
- Avoid pseudonyms:
- They reduce the chances that your matches will find you or
look at your family
tree, contact you or share the information about your ancestry that
they have and that you do not have.
- Be consistent and avoid unnecessary confusion:
- A real example (further anonymised):
- Ancestry username: tara1234
- AncestryDNA samples from mother and daughter (per
- linked to pedigree charts of an aunt and niece
- appear to matches as M.R. (managed by tara1234) and
D.C. (managed by tara1234)
- neither of these are the real initials
- mother's GEDmatch alias and e-mail address both begin
- Molly is the dog's name
- it took me
- 300 days after the mother's GEDmatch upload
to associate her AncestryDNA and GEDmatch identities
- 2 days to get her to upload her daughter's data
- Keep all your DNA-related correspondence in a single
searchable e-mail archive
- Use AncestryDNA, MyHeritage or Facebook messages only to exchange
After you get
your DNA results ...
- Download your raw data from FTDNA or AncestryDNA
or MyHeritage and upload to GEDmatch and/or FTDNA (free autosomal
transfer) and/or MyHeritage.
- Create and upload an updated GEDCOM file with any new close
cousins or ancestors that come to light.
- Add DNA information to your genealogy database: use an
event field or note tag in your database to
people who are in both your database and the DNA databases.
A case study: The
McMahons of Querrin
The oral evidence
- My friends Michael and Martin know that they are second cousins, with
common greatgrandparents John McMahon and Honor Hanrahan, whose family was in
Querrin in 1901 and 1911.
- They know that they are closely related to one of the other
families in Querrin in 1901 and 1911, headed by the twice-married
- These McMahons are said to have originally come to Querrin
(in Carrigaholt parish) "from Doonaghboy side" (in Kilkee parish).
- Just 9.1km according to Google
- There were 2,867 McMahons among the 104,453
enumerated in Clare in 1911 (2.7%), including many more within a 10km
radius of Querrin.
- The third McMahon family in Querrin came from Carrowncalla
South in Kilrush parish shortly before 1901.
The archival evidence (online)
- The only marriage of John McMahon of Querrin took
place in Carrigaholt parish on 28? January 1861,
before civil registration of Catholic marriages began on 1 January 1864.
- Both marriages of Martin McMahon of Querrin took place
after 1 January 1864, in 1870 and 1887.
- Both civil records show that his father was Michael
- Martin McMahon was 25 when he first married in 1870, 54 in
1901, 68 in 1911 and 87 when he died in 1928, so b. Abt 1840/1847.
- John McMahon was 70 in Mar 1901 but only 72 when he died in
Jul 1904, so b. Abt 1830/1832.
- Were they brothers? If so, then who was their mother?
- In Griffith's
Valuation in 1855, Michael McMahon occupied a house and
office on 25a 3r 29p in Querrin (no. 48a).
- The askaboutireland.ie maps of Querrin
show many changes to farm boundaries in the years after Griffith's
Valuation, but no. 48a remained largely unchanged (screengrab).
- John McMahon is buried in Kilfearagh:
Michael McMahon in
memory of his father
John who died July 22nd
1904 Aged 72 yrs. Also
his Sister Bridg't died
Jan'y 6th 1895 Aged 26 yrs
The archival evidence (offline)
- I photographed the Valuation Office cancelled
books for Querrin DED on 15 February 2018.
- The online maps, passed off as "Griffith" as if from 1855,
show numbering changes not made until 1876.
- no. 48a remained unchanged apart from an increase in area
of 23 perches in 1898, and a large increase in the rateable annual
valuation of the buildings in 1943, probably reflecting a new house.
- no. 48a passed from Michael McMahon to Mary (his widow?) in
1864, to Michael's son Martin in 1872, to Martin's son Timothy in 1926,
and to Timothy's son Michael in 1964.
- Around 1859, Michael McMahon and his neighbour Michael
McGrath (no. 49a) replaced Patrick Foley as joint occupiers of a
re-drawn non-residential no. 33.
- no. 33a passed from Michael McMahon to John (his son?) in May 1864
a house was built), to John's widow Honor in 1906, to their son Michael
in 1909, to Michael's widow Kate in 1931, and to their son John in 1941.
- Were the McMahons and McGraths related?
- Oral tradition tells us that a McGrath widow and children in
no. 49a sold up and went to America after her husband was killed in a
horse and car accident; Valuation Office records confirm that the Roche
family bought the McGrath farm around 1893; will McGrath descendants
show up as DNA matches to McMahon descendants?
The DNA evidence
- I swabbed Michael on 23 November 2015.
- I swabbed Martin on 23 February 2016.
- They waited impatiently for close matches until Carole
AncestryDNA results (twice) to GEDmatch, initially on 1 Feb 2018.
- Carole's Total cM shared was 43.6 with Martin and 62.6 with
- She first reported that her "great grandfather Timothy
Garvey McMahon was born in Kilkee & came to Australia in the
- She also knew that her GGgrandparents were Michael McMahon
and Mary Garvey.
- Australian marriage and death records often name Irish ancestors who are absent from surviving Irish records.
- "Go sideways in order to go backwards".
Revisiting the sources
- Sometimes one can fail to see that the critical clue in a
genealogical puzzle is literally right under one's nose.
- Back to the Kilfearagh transcriptions:
This Tomb Was Erected
by Mary Garvey alias
McMahon in memory
of her beloved husband
Ml. McMahon who dep'd
this life 20th of septem
1861 aged 57 years
may he rest in peace
P. Cusack [photograph]
- The two McMahon graves are numbered 492 and 493 in the list
- The 1980s sketch map of Kilfearagh has
- Graves 492 and 493 are right beside each other.
- The earliest surviving Kilkee baptismal register goes back
to 1836 but has never been microfilmed.
- Two visits to the parish office confirmed that it includes
four children of Michael McMahon and Mary Garvey between 1837 and 1846,
all with address given as "Kilfera" (near Doonaghboy), including two Martins but no John.
- The register fell apart and has been rebound, so dates are
very difficult to decipher, but the last Martin appears to have been
baptised in 1842 or 1843, in the middle of the range of implied birth
years from later sources.
- So the McMahon family appears to have moved from Kilfearagh to
Querrin between the last Kilkee baptism (1846) and Griffith's Valuation
- Two visits to Kilfearagh cemetery followed and the second
revealed a relatively
lichen-covered headstone sitting on top of the old flat
- Grass, talcum powder and other tricks of the trade weren't much help.
- Mirrors started to do the trick:
In loving memory
also his sons
- So the two McMahon families who lived at opposite sides of
Nash's Cross in Querrin are buried in adjoining graves, with Martin McMahon's
family sharing a grave with Carole's ancestors.
- We still have not proven that Carole is a third cousin to
Michael and Martin, the greatgrandsons of John McMahon in the other
- We knew that Johnnie, another greatgrandson of John McMahon
and Honor Hanrahan and a second cousin of both Michael and Martin, had
spat for AncestryDNA as a favour for someone researching his father's
- AncestryDNA reports 165 centiMorgans shared
across 8 DNA segments between Johnnie and Carole.
- There is less than 3% probability of people sharing this
much DNA being more distantly related than third cousins.
- Their AncestryDNA shared matches include two people in Johnnie's
"3RD COUSIN" bucket, both also known descendants of John McMahon and
- Beware such misleadingly precise headings: one is Johnnie's
second cousin once removed, the other his first cousin twice removed;
less informed customers may not understand that these
headings are not the exact relationship.
- There are five descendants of John McMahon and Honor
Hanrahan at AncestryDNA who are not yet at GEDmatch despite our best
- Getting all eight probable descendants of Michael McMahon
and Mary Garvey onto GEDmatch and running the autosomal matrix tool may remove
any remaining doubts.
Conclusion: Why you should submit your DNA
- The value of DNA "testing"
to genealogists increases dramatically with the number of people from
the relevant geographical area and relevant extended family group
already in the DNA databases used.
- Submitting your DNA to a
database has significant positive externalities for existing and future
- We need to persuade more Galway people, and
Irish people in general, to submit
DNA samples to the databases for purely genealogical purposes.
- Your descendants will be eternally
grateful to you for leaving them your DNA.
- See here for all the technical details
of how and why to
upload your DNA data and pedigree charts to the various websites.