I’ve been planning
to share my experience with having my DNA tested for a while, but now seems the
perfect time since I am taking an online Genealogy course through Future Learn
and this week’s class was about genetic genealogy! So a big shout out to Graham
Holton at the University of Strathclyde for explaining such a complicated subject
in such an easy to understand way!
There are a
few different types of DNA testing: Y-DNA STR, Y-DNA SNP, Autosomal (atDNA) and
Mitochondrial (mtDNA).
Y-DNA Tests: These tests can only be done on
males. STRs (Short Tandem Repeats) are repeated patterns of chemical bases that
can be measured in the Y chromosome. STRs look for similarities between results
because closely matching results indicate descent from a common male line
ancestor. STRs are useful for genealogy because they measure the number of
repeats at selected locations. They are useful for the period around 1500, but
are unreliable for periods prior to that. Mutations occur at different rates,
for example, in a 500 year period, one family could have 1 mutation, while
another family has 3 mutations.
There are 2
major types of mutation, which are relevant for genealogists. The first
involves changes in STRs, the second involves mutations known as SNPs (Single
Nucleotide Polymorphism). SNPs occur when a single chemical base in the DNA
changes at a specific location. Once a SNP mutation occurs it is usually
permanent, unlike STRs which are prone to further changes. SNPs can be used to
identify a specific branch of descendants because of their stable nature.
Prior to recent advancements SNPs
could only be able to be used to distinguish between different branches of very
large genetic groupings thousands of years ago. However, now we can see SNPs
that occurred hundreds of years ago, during a time of recorded history,
therefore making it easier to decipher more specific groupings. For example,
SNP CLD51 indicates descent from the Macdonalds of Kinlochmoidart, who are
descended from John Macdonald, 9th of Clanranald, who died in 1593. Through
DNA testing, a student at the University of Strathclyde was found to be a
descendant.
Autosomal DNA Test: Autosomal tests are useful for both
males and females because it gives information on all ancestral lines (father’s
mother’s line, mother’s father’s line, mother’s mother’s line, etc.). At
present, Autosomal tests are good for going back around 5 generations with
confidence. Furthermore, if a number of known relatives take this test it is
possible to identify which segments of DNA have been inherited from specific
ancestral lines. This test gives information on the X chromosome, and also
indicates a percentage of your ancestry that comes from various geographical
origins. I did the Autosomal DNA test so I will have an example of this when I
discuss my results (see Ancestry Composition).
Mitochondrial DNA Test: mtDNA testing is the opposite of
Y-DNA testing, (mother to daughter instead of father to son), however, mtDNA is
also passed from mother to son, but cannot be passed on by sons. There are
fewer mutations with mtDNA than Y-DNA which means it isn’t good at telling us
if we are related to an individual with a close genetic match. However, it can
show you a probable common female line ancestor from about 400 to 500 years ago,
and which part of the world a female line ancestor lived in several thousand
years ago.
MY DNA RESULTS
I took the Autosomal
DNA test through 23andMe. All of the information below is from 23andMe. It will
cover ancestry composition, my maternal line haplogroup information and
Neanderthal ancestry information. Since only males carry the Y DNA I do not have
results for my paternal line haplogroup. A male relative, from my father’s line,
would have to take this test in order for me to get these results. I had hoped
to find a match through DNA testing but haven’t… yet. Fingers crossed!
Ancestry Composition:
99.3% European
65.9% British & Irish
5.7% Scandinavian
5.2% French & German
21.5% Broadly Northwestern European
0.4% Iberia
<0.1% Broadly Southern European
0.1% Ashkenazi
0.4% Broadly European
0.3% Middle Eastern and North African
0.2% North African
0.1% Broadly Middle
Eastern & North African
0.1% South Asian
0.1% Sub-Saharan African - West
African
0.1% Yakut
0.1% Unassigned
Maternal Line:
My maternal line haplogroup is H8, an
ancient subgroup of H, tracing back to present-day Turkey and Syria around
30,000 years ago. H8 migrated to the Altay Mountains of Central Asian.
Fun fact: Famous
people from Haplogroup H are Luke the Evangelist, Marie Antoinette, Napoleon
Bonaparte, Prince Philip and Susan Sarandon.
Neanderthal Ancestry:
It is estimated that my genome-wide
percentage of Neanderthal is 2.6. Neanderthal characteristics are heavy eyebrow
ridge; long, low bigger skull; and prominent nose with developed nasal chambers
for cold-air protection. I am ranked 57th among my matches on
23andMe, some with a percentage as low as 1.3%, some as high as 3.4%.
Although the
Neanderthal percentage was a fun portion of my testing, the truly helpful part
was the matches to other users at 23andMe. To date I have 854 DNA relatives
just on the 23andMe site alone. I also upload my results to GEDmatch.com and
have found further matches there, although I haven’t done much with that yet
since I’ve barely scratched the surface with my original matches on 23andMe.
I have been
fairly selective in sending invitations to matches because it can be incredibly
overwhelming when you get a high volume of responses all at once. I tend to
send messages/an invitation to share genomes to closer DNA relative matches (2nd
to 4th cousins) because it is easier to find the shared ancestor
with a closer matching relative than a distant relative, although I will also
contact distant relatives if they have surnames and geographical locations that
match my genealogy research. Most of my matches are 3rd to distant
cousins. I’ve been matched to three 2nd-4th cousins, but
1 is “private” so I can’t contact them. He’s a male from Northern Europe and we
share 4 segments of DNA. Which is cool to know, but I can’t really do anything with
this information without knowing the specifics, such as which segments we
share, what some of his ancestors’ surnames are, etc. Grr! I’m waiting for a
response from the other two.
I’ve had two
successful matches, where we could pinpoint our shared ancestor. That’s been
very exciting, since one was confirming the ancestral line of my great
grandmother’s biological father. She was adopted so that was the information I needed
to confirm my genealogical research, and it was the initial reason I did DNA
testing to begin with! That was a fantastic day.
Now I’m
hoping to find a male ancestor on my father’s line (Farrer), so that I can find
out his haplogroup. So far, no luck, but sometimes with genealogy research, it’s
a matter of patience; waiting for new information to emerge. I have recently
found a cousin from my Farrer line, however, he is a descendant from a female
in that line so he has a different haplogroup. Without the benefit of DNA
testing I would never have known of this cousin. Now I have his ancestors’
names and locations that I can compare with my own research to find our shared
ancestor. What I know so far is that his Farrer ancestors and mine were in the
same geographical location, in the same time frame and have the same surname. I’m
confident this is our probable connection. Now I just need to figure it out! Which
is why my kitchen table and office wall look like this…
Happy
hunting, fellow gene geeks!
