10:30 a.m. Friday 11 May 2018
- Project established 16 July 2017.
- Circular e-mail to O Dea Clan sent 18 October 2017.
- DNA (short for deoxyribonucleic
- inherited by all living organisms from their parents;
- made up of chromosomes and mitochondria, each consisting
molecules of four nucleotides
named adenine (A), cytosine (C), guanine (G) and
- represented by strings of the letters A, C, G and T.
- All surname groups are now using DNA for family research.
Where does our Human 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.
DNA from males is widely used for one name studies or surname projects
such as the O'Dea/O'Day/Dee DNA Project hosted
- Autosomal DNA comparison is heavily marketed to males and
females by several companies including AncestryDNA.
- 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?
Mutations: STRs, SNPs and Haplogroups
Most DNA is transcribed exactly from the relevant parent to the child.
are transcription errors at single locations, e.g. a single A in the
parent may be replaced by a C in the child.
Some locations mutate very frequently (every couple of generations),
and can be used to identify
individuals beyond reasonable doubt, e.g. in criminal cases.
Some locations mutate less frequently (only once in many generations or
once in the history of mankind), and can be used to identify
closely or distantly related individuals.
Special types of mutations:
FamilyTreeDNA will (for a fee)
examine your Y chromosome (if you have one) for both STR and SNP
- Short Tandem Repeat (STR): a string of
letters consisting of the
same short substring repeated several times, for example
CCTGCCTGCCTGCCTGCCTGCCTGCCTG is CCTG repeated seven times; it may be
repeated less or more often in other individuals.
- Single Nucleotide Polymorphism (SNP): a single location
where two (or occasionally more than two) different letters are
observed in different
STR mutations can reverse or repeat in later generations, but some SNP
mutations on the Y chromosome are once-in-the-history-of-mankind
These mutations have occurred exactly once. Every man
descended from the man in whom the mutation originally occurred
inherits the mutation. No other man has the mutation. When discovered,
each of these SNPs is given a label consisting of letters followed by
numbers, occasionally including an underscore (_), e.g. L226 or FGC5660
Men with a more recent SNP may share older SNPs with men who don't have
the recent one.
Note that surname spellings also mutate, independently of DNA
mutations, e.g. Ó Deaghaidh to O'Dea to O'Day.
The Pros and Cons of Public DNA Comparison
- There is a trade-off between:
- increasing your chances of proving your relationship to
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
and the DNA of all of your relatives out of the online databases.
Submitting DNA Samples
The entry-level Y-DNA product is now Y-DNA37, which
looks at the numbers of repeats for
each of 37 STR markers on the Y
chromosome, e.g. the O'Dea/O'Day/Dee DNA Project.
You may want to turn off usually irrelevant Y-12 and Y-25 match
notification e-mails on the Notification Preferences page.
In return for your DNA sample, you will get:
The word haplogroup
been used to describe any group of men with similar Y-DNA (or a group
of people with similar mtDNA):
- a match list; and
- a predicted haplogroup
or terminal SNP.
SNPs can be used to build a Y-DNA Haplogroup Tree or haplotree, with more
recent SNPs shown as children of older SNPs.
- originally, a haplogroup referred to a group of men with
similar patterns of STR values;
- as the science of analysing the Y chromosome has evolved, a
haplogroup has come to refer to a group of men with the same SNP
Some branches of the haplotree:
There has been a SNP Tsunami in recent years: from about 800 SNPs in
2012 to more than 35,000 SNPs by 2015.
The Y chromosome is only 59,373,566 letters long, so there is an upper
bound to the number of SNPs that may eventually be discovered.
Men with the same
SNP mutation tend to also have similar patterns of STR mutations, so
STR mutations are used to predict SNP mutations.
uses "haplogroup" (on the Y-DNA Colorized Chart)
interchangeably with "Terminal SNP" (on the Y-DNA - Matches page).
STRs can only predict
Y haplogroups but a SNP product must then be purchased to confirm the
- FTDNA's automated SNP predictor plays safe and confidently
predicts only high-level (ancient) SNPs, e.g. R-M269
- Project administrators can usually, if less confidently,
predict more recent SNP mutations and can group members into
predicted haplogroups with their closest relatives on the project results page.
Known relatives should pool their funds to purchase more advanced
testing or donate to the project, rather than
waste money merely confirming known relationships.
- single SNP
- SNP pack
- Big Y500
Donations to the project must be used to purchase FTDNA products for
members and can not be used for any other purpose.
Overlaying SNPs and Surnames
The Irish annals tell us that Cas was the "father" of the O'Deas,
O'Briens, O'Quinns, MacNamaras and other surnames - the Dalcassian surnames.
Deaghaidh, from whom the surname is derived, lived 12 generations
before Conor, victorious in battle 700 years ago this week, so it is
not strictly correct to claim Conor as "our great ancestor".
Genetic similarities are being found between men with these related
They generally have Irish Type III DNA characterised
by the L226 SNP in Haplogroup R.
There is a project set up at Family Tree DNA for the
Many thanks to Dennis Wright, Dennis O'Brien and Robert Casey who
administer that project for all their advice on interpreting O'Dea
Surname-specific SNPs are now
being discovered and will eventually be discovered for the O'Dea
The O'Dea/O'Day/Dee DNA Project
- If you have any O'Dea ancestry, then please contribute your
genealogy AND your DNA to the project.
- DNA kits and discount codes are available at the DNA
Workshop after lunch today (no shipping cost).
- No eating, drinking, smoking, chewing gum or brushing teeth
for one hour before swabbing to ensure a clean DNA sample.
- This is one of thousands of surname projects
hosted by FamilyTreeDNA.
- There are also geographic projects, e.g. the Clare Roots project.
- The O'Dea/O'Day/Dee project administrators are:
- James O Dea of the Dysert O'Dea Clan Association; and
- Paddy Waldron (GGGGgrandson of an O'Dea).
- If you are not already a project member, then please JOIN
the project by clicking on the JOIN button here. You will be prompted to log
in to your FamilyTreeDNA account if you have one, or to order
a kit if you do not.
- If you are not yet an FTDNA customer but have submitted a
DNA sample to one of the other DNA companies (e.g. AncestryDNA), then
you may be able to copy your autosomal DNA data to FamilyTreeDNA.com
via the free Autosomal
Transfer and should do this before joining any projects.
- The project emphasis is on O'Dea Y-DNA.
- If you are a male O'Dea, then please order at least Y-DNA37.
- If you are not a male O'Dea, then please persuade your male
O'Dea relatives to order at least Y-DNA37.
- In order that you and the other members can benefit from
your membership of the project, it is imperative that you:
- squeeze in names, dates
and places to the 50 characters allowed for both
your Direct Maternal (i.e. matrilineal) and Direct Paternal (i.e.
patrilineal) Most Distant (i.e. most distant known) Ancestors here
in order to help those looking for mitochondrial DNA matches and Y-DNA
- upload a GEDCOM file here
showing your direct ancestors (which will automatically populate your
surname list); and
- adjust your privacy settings
so that you can be seen on the project results page (Group Project
Profile: Opt in to Sharing; and Family Tree Sharing: Public).
- Please feel free to use the Activity
Feed to direct any questions that you may have to the project
administrators and for discussion with other project members.
The Y-DNA Results
The results reveal various different independent genetic origins of the
O Dea surname, both inside and outside the Dalcassian branch of the
The O'Dea/O'Day/Dee Surname Project now has 52 members with STR
results visible to project members and administrators, of whom 27 have
made their STR results visible to the public. So remember to
log in to your FTDNA account if you want to see the full results table;
and to adjust your privacy settings if you want others to see you in
the full results table..
Surname spelling distribution:
I have provisionally divided these members into 18 O'Dea subgroups,
based mainly on their STR results, with a residual group for those
whose O'Dea ancestry which is not through the
- 13 are O'Days
- 14 are O'Deas
- 10 are Days
- 1 is a Dea
- 1 is a Dee
- 1 is an Odey
- 1 is a Godwin
- 2 have other surnames, with a confirmed recent
surname/DNA switch and O'Dea male-line
ancestry shown in the Paternal Ancestor Name column
- 2 have other surnames, but suspect a surname/DNA switch in
- 2 have other surnames, but have close genetic matches to
O'Deas which may (or may not) pre-date the adoption of surnames
- 5 (including myself) are from non-O'Dea male lines but have
O'Dea ancestry which is not through the
So far, sixteen of the men whose surname is O'Dea or a variant have
given a placename in the Paternal Ancestor Name column, eleven in
Ireland (Counties Clare, Cork, Galway and Limerick and one from an
unspecified county), two (known relatives) in Wales, one in Canada and
one in the USA.
The confirmed terminal SNPs for men in the O'Dea subgroups to date are:
(Heat maps from Wikimedia Commons.)
The Dalcassian O'Deas: Breaking News
FGC5660, DC135, DC134 and BY5212 are descendants of the
better-known R-L226 (Irish Type III or Dalcassian Y-DNA signature),
which accounts for
over half of the O'Dea men in the project (27 out of 52).
Almost all L226+ men are also FGC5660+.
The O'Dea with terminal SNP L226 has bought only the single SNP L226
test, so is probably also FGC5660+.
John B O'Day III was the first
Dalcassian O'Day or O'Dea to buy BigY:
Commentary by Dennis O'Brien and Robert Casey of the L226 project:
- L226+ confirmed by single SNP test ordered 20 Dec 2013
- Big Y ordered 27 Jan 2018
- gDNAQC and HiYNGS results completed 13 Apr 2018
- haplogroup/terminal SNP remained L226 ???
- more recent SNPs hidden away in the haplotree:
- anomaly discovered, reported and recitifed 10 May 2018
- Conor Myles John O'Brien 18th Baron Inchiquin is:
- In fact, YFS231286 is an O'Brien-specific
- Did all the fostering back and forth between O'Briens and
O'Deas result in a surname/DNA switch?
"Where has this member come from?
Within the L226+ subgroup, one O'Dea has tested positive for DC135 (and
hence must be DC8+ according to the FTDNA haplotree) but another is
DC8- and two are DC8*. This raises the question as to whether
the DC8 mutation or the adoption of the O'Dea surname by this group of O'Deas came
first. So far, there are only four men in this branch of The Big Tree and none of them is
an O'Dea (or variant). There are several Crow/Crowe/Croke men on the
DC135 branch which suggests a close connection between those surnames
and O'Dea. One of the Crokes has joined the O'Dea project.
If he is BY5212+ then he should certainly be in the O’Brien Surname Project like Morrissey.
As YFS231286 is certainly a “Thomond” SNP of around 1300AD, this person
has to be either a NPE, adoption or political surname change.
What do we know about his history?
Except for Morrissey, this has not happened, to our knowledge, before."
"This puts you at a descendant of King Brian Boru.
I highly recommend that you upgrade this person to either 67
markers or 111 markers.
The L226 O'Dea testers belong to at least five different branches (both confirmed and predicted) under L226 that would not
share a common ancestor with the O'Dea surname [see L226 results page]:
Group 11: FGC5660/Z17669- 4 67 markers (Kilteely group)
1 67 markers (kit 84924? Not in O'Dea project?)
DC63 1 67 markers (kit 517547)
Group 74a: BY5212 1 37 markers (John B O'Day III)
Group 12a: DC135 1 37 markers (James O Dea)
Then there are five more O'Dea testers at 37 markers that could
predicted at 67 markers."
So far, there are only seven Big Y500 (formerly known as BigY) results
in the project, with most recent confirmed SNPs:
One objective of the project is to
identify one or more O'Dea-specific SNPs within the R-L226 subgroup. This will
require more O'Deas (or variants) from that subgroup to purchase Big
Y500. With any luck, another man with Big Y500 results will eventually share one of the novel variants of an
existing Big Y500 subject, which will then be deemed to be a new SNP.
- E-BY4507 (O'Day)
- R-L226 (O'Day)
- R-Z16443 (O'Day)
- R-FGC11986 (Day)
- R-DC134 (Croke); and
- R-BY13083 (McGillivray,
with a female O'Dea ancestor).
My own O'Dea Ancestry
- My Family Finder results are dated 15 Nov 2013.
- My paternal and maternal first cousin's results are dated
- Paternal first cousin's closest match had an e-mail in a Texas
- I mentioned this to his Limerick namesake on 2 Sep 2014 and
discovered that they were the same person!
- We compared what we knew and found that we both had
ancestors in Ballybrown and were both somehow related to John Smith
(1849-1909) of Adare.
- My GGGGgrandfather John Keas (c1777-1845) farmed first in
Conigar (now part of the Irish Cement site) and then in Ballyveloge,
where he first leased a 145-acre farm in 1819 (Registry of Deeds, book
840 page 259 deed 563759).
- John Keas was grandfather of John Smith.
- The match's GGgrandparents John Ryan and Bridget O'Dea married in Ballybrown, Lurriga
& Patrickswell Catholic parish on 21 Feb 1821 (no. 469).
- John Smith (who married into the business in 1877) employed
the young Denis Ryan (1858-1928), grandson of John Ryan and Bridget
O'Dea, and is
reported to have later said to Denis Ryan: "Why didn't you tell me you
were related to me?"
- Lease of Ballyveloge "for and during and untill the full
end and term of the natural life and lives of Edward Keas, 2nd son, of
the said lessee and John Keas, 3rd son of said lessee and William Keas,
6th son of the said lessee" (Registry of Deeds, Book 858 page
327 deed 572827)
- Edward Keas remained in Conigar when the rest of the Keas
family moved around 1819 from a parish
with no surviving baptismal records today (Mungret) to an adjoining
parish with surviving baptismal records (Ballybrown, Lurriga &
- John Keas and John Keas Jnr., although apparently Catholic,
signed the minutes of a Vestry of
the Established Church
legally called and held at Kilkeedy Church (now in ruins) on 17 Dec
- William Keas was baptised
in Ballybrown, Lurriga & Patrickswell on 31 Oct 1821
"ex Joanne Keas et Maria O'Dea" (no. 1798).
- So John Smith and Denis Ryan each had an O'Dea grandmother!
- Were they sisters? Or is the age difference too large?
Maria's last child was born the year that Bridget married.
- Almost certainly both were daughters of Edward O'Dea, after
whom they named sons.
- A possible third sister was William Keas's godmother,
probably the Anna O'Dea who married James
Patrickswell parish on 7 Jun 1825 and had children baptised in
Sixmilebridge parish between 1832 and 1844.
- But which of the many James Frosts in that parish was
- Relationship diagram
- Autosomal matrix
- But whatever became of William Keas?
- Recruit more members
- Upgrade more members to Big Y-500 (Big Y + Y111)
- Confirm terminal SNPs for existing members
- Use SAPP to generate a mutation
- Use Robert Casey's methodology to predict SNPs more
precisely from STRs.
- Further reading on Y-DNA