Sunday, January 15, 2017

A Puerto Rican Look at: 23andMe's Ancestry Timeline

So it's been a while since I've posted and it's already 2017! As the new school year kicked off I saw myself being less and less able to write on the blog, despite having some new blog ideas! So finally I'm back and hopefully I'll continue to post throughout the year evenly and not in chunks. The reason I want to post today is because there is a new feature on 23andme and I'm excited to see how this feature can help discover or clarify more about my past. The feature is called "Ancestry Timeline" and I want to take a look at how this feature works through the lens of a Puerto Rican -- myself and my family! As a reminder, how is what my genetic breakdown looks like:

23andme results [personal photo]

I'm not sure exactly when the Ancestry Timeline feature was released but one of my genetic cousins posted her results on Facebook and so I had to go in and check mine! Here's what it looks like for me:

Ancestry Timeline [personal photo]

There you can see a couple of things you can see. First you can see colored bars which represent various different populations used to test against your DNA. Next on the top you can see various numbers and years, these represent approximately when that ancestor would have been alive in your family tree. There are, however, a few things to take into consideration, of course. Reading their white paper I was able to see a few things I should look out for as I consider these results. 

Translating Generations [23andme]

Not everyone's family follows the same trend of generation years, though the average is 30 and it is usually held that way just to estimate generations it can vary in your family. For example, I have fairly young parents and grandparents but before that it varies. My oldest great-grandparent was born in 1884 while my youngest great-grandparent was born in 1923 - a whole 39 years between them! Just remember that as you look at your own timeline. 

Violations of the "one genealogical ancestor" assumption [23andme]

In my case, I am sure that there are multiple ancestors that carry for example African genes, so I wouldn't be able to know exactly where and when this ancestor would have been alive in my timeline. Besides an 100% ancestor, who would be one of my 4th great grandparents, it is hard to know which of the segments combined or didn't to give me my 15.7% African DNA. 

Nonetheless, the results are very interesting and I think there is some truth to the timeline. Also, it would be interesting to compare my results to my parents' as well. It's interesting that my "Iberian" bar shows up between 1900-1840 while my parents and other tested family members have it at about 1860-1800. Initially I thought it was representing my 3rd great grandfather who lived around 1846-1910 and was from Mallorca, but shouldn't it appear for my father and great-aunt in the same spot since we share that common bar so recently? Equally interesting is my West African bar which appears between 1840-1750 and it states that "you most likely had a third great-grandparent, four great-grandparent, fifth great-grandparent, or sixth great-grandparent who was 100% West African". This does coincide with my 4th great-grandmother who was born in 1844 and was the daughter of two slaves in Martinique. But it's also important to notice that there are more ancestors in my tree somewhere that contribute to that West African bar. Bars like "Chinese" and "South Asian" represent only <0.1% of my DNA and I'm guessing that's just noise so I'm surprised that such a small percentage would show up here. 

It'll be interesting to see how other people can use this to find out certain information about themselves. For us new world people, it's interesting to see where time wise they place these bars and I would like to see how accurate or close to accurate they are for others. For me, I've seen some coincidences and based on what I know about my family they seem to correlate with the information. Excited to see where this heads! 

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