Genetic Genealogy and Me

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, 9^th 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 57^th 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 (2^nd to 4^th 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 3^rd to distant cousins. I’ve been matched to three 2^nd-4^th 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!