This is Part 2 in the series, “The Autosomal Me.” Part 1 was “The Autosomal Me – UnRaveling Minority Admixture.”
Every Sunday, I write something called a Sunday Story. I’ve done this for years. I send them to my kids and I delude myself into thinking they read them. I’m really writing them for my grandkids someday and hopefully, some as yet unborn descendants I’ll have that will care about finding out about the life and times of their a-few-greats grandmother who lived along with the dinosaurs in the last half of the 1900s and first half of the 2000s. I know, I’m optimistic.
I decided that perhaps I would share this weeks Sunday story with all of you. This way, I know that at least someone will read it. Actually, aside from my husband, it’s my daughter-in-law who comments the most often. So welcome to my Sunday Story! You are all honorary cousins!
I know that a great deal of what I do with genetics is lost on my friends and family members. That’s OK, because it’s very specialized. However, I wanted to take a little bit of time to share with you an aspect of the genetics I work with that I think is very beautiful in both a literal and a spiritual way.
The point of genetic genealogy, of course, is to learn about our ancestors, who they were and our connection to them. There are various ways to do this, but most of the time it’s through various matches to other people who share a common ancestor either recently or perhaps further back in time.
Of course, therein lies the rub – how long ago are two people related and who was their common ancestor? Some people who carry minority ancestry are at a distinct disadvantage, because the testing that provides matches and ethnicity generally relies on amounts in excess of 1%, which equates to about 6 or 7 generations. While many of us know that we carry minority ancestry, we would be hard pressed to say that our “pure” Native (or other minority) ancestor fell into that 6 or 7 generation bracket. Six or 7 generations equates to about 150-175 years before our birth, or about 1775-1800 for most of us. By then, many Native people were already admixed and many already lived outside of a traditional tribal unit. Some people carry Native heritage from multiple lines, but since it comes from multiple ancestors, it too is often quite fragmented, so it doesn’t really improve the situation much unless some of those fragments happen to fall together to make larger segments.
Therefore, we are looking for very small amounts of admixture that often don’t show on traditional tests, or if they do, it’s in miniscule amounts.
Enter chromosome painting.
Without going in to boring detail, I’ve recently been working with a new methodology of identifying these fragmented and very small segments. I am using several chromosome painting tools. I’ll be blogging soon enough about how all of this is done, but I just wanted to share with you a couple of beautiful pieces of DNA, through which our ancestors are speaking, and we can see them, in a manner of speaking.
On the graph below, which is my chromosome painting of one a small part of one of my chromosomes on the top, and my mother’s showing the exact same segment on the bottom, the various types of ethnicity are colored, or painted. You can see that both of us have a primary ethnicity of North European, shown by the teal.
The grid shows location 120 on the chromosome. Think of this number as a house number on a street. It’s numbered so we can keep track of where we are on the chromosome. For genealogy purposes, the smallest segment normally considered as relevant is 7 mb or marker segments long. Each tick mark equals one segment or address, so a segment 7 mb long would be from 120-127 which takes you right over to the legend. As you can see, the primary ethnicity has no problem reaching way beyond the contiguous 7 threshold, but the minority ethnicity would not be counted because it’s too small.
However, by the very definition of what minority ancestry is, these small segments are not only present, providing critical information, they are essential in our search and very informative. Let’s see what they are saying to us.
First, let’s talk for a minute about ancestry. There is no line in the sand very often between populations. There are generally only degrees of difference. So in the case of Native American, which is yellow on this chart, we also expect to see it “drift back in time” by being found in conjunction with Siberian (putty), South Asian (red) and East Asian (emerald green). Native Americans were not dropped from alien spaceships, they evolved over time from these other Asian populations, so we would expect to see some of their genetics in Native American people.
So let’s take a look at what we do actually see in the DNA.
The first brightly colored segment in the top band is mine. It includes Native American (yellow), South Asian (red), a big chunk of East Asian (emerald Green), a little bit from the Caucus (ginger) which is the Middle East area, and a piece of West African (light green).
There are two messages from the ancestors in this piece of DNA. First, this segment absolutely, positively does NOT come from mother. We can see this clearly because she has nothing but North European (teal) in that section of her DNA. So, this little gem came from Dad.
The second piece of information is that the ancestor who provided this DNA to Dad was very likely admixed, Native and African.
Of course, if you’re thinking ahead at this point, you’ll be asking, “Which one of your Dad’s other relatives has this same segment?” because, yes, that’s exactly how we will tell which of his lines contributed the Native ancestry. But you’re getting ahead of the story, and well, that is a story for another time. This story today, is about the direct messages of the ancestors and the beauty of our DNA itself.
Let’s look at the next segment of minority DNA. It starts about location 123. Mom’s is much more pronounced than mine and much richer. This tells us that I didn’t receive much of Mom’s. Instead I received mostly North European (teal), along with some East Asian (emerald).
Mom has almost a perfect Native segment here. By perfect, I mean we find a progression from Native back through time through all 4 categories I would expect to find. I consider this entire segment “Native” because it indicates Native heritage. You can see the emerald green (East Asian), putty (Siberian), red (South Asian) and yellow (North American Indian and Arctic) nestled together with no other minority ancestry in close proximity. This means it’s not part of a different kind of Asian segment. Remember, part of Europe was settled by the Mongol Hordes and the Huns, so we do see Asian and western Asian DNA in Europe, along with DNA from the Caucus, but we don’t see isolated segments like this, with just eastern Asian DNA and Native American. So this little beauty is the perfect Native indicator, positively, even though it is only about 4 segments long.
Now take a look at my DNA in that same region in the top row. It’s kind of hard to see the emerald green against the teal, but I only inherited the East Asian (emerald) segments from Mom. Of note, however, is that I also have an East Asian (green) segment that Mom doesn’t have. My East Asian starts about 122 where hers doesn’t begin until 123. So good old Dad contributed a bit here as well. Again, we know this because Mom only has North European at that segment.
And now of course for the kicker. Your DNA looks this same way. How boringly teal it is, or how beautifully rainbow multi-colored depends on how much minority ancestry you have, from how many different lines, and which of your parents you received it from.
I hope you can see why I’m so excited to be developing this new technique to work with highly fragmented DNA to find our ancestors. They are there, they have a voice, and they are speaking to us. All we have to do is figure out how to listen.
I am simply in awe of the beauty of this technique, literally as well as figuratively. While I certainly understand and appreciate logically that matching other people means we’re related, there is something awe-inspiring and tangible about being able to see the painted graphs and view the layers of ancestry nestled together, life forces reaching through time, protecting that DNA with its precious message for us over many generations. All this time, just waiting for us to be able to understand the most personal message from our ancestors, delivered, from them, in our genes, to each of us. This is the voice of our ancestors.
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