I’m African American. Hypothetically, a thousand or so years ago, say my ancestor was an Asian (For example) who married a Black person. Naturally, their child was 1/2 Black and 1/2 Asian. That child went on to marry a Black person. The ancestry continues on and on for many years until we’re in 2022.
Coincidentally, none of the children ever married an Asian and all of the people they married had no trace of Asian blood in their lineage, making that one ancestor the only trace of Asian in me.
But do I still have Asian in me? What fraction would that even look like? Or at some point does it get “erased” as a result of being reduced by the other races, bloodlines, etc. over the course of 1000+ years?
I hope the example I gave makes sense. I guess I’m basically asking if, at some point, race/lineage gets erased from your cells/DNA if that race hasn’t been present at all in your family for several centuries.
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I take it you are referring to DNA tests like AncestryDNA and 23andme.
I understand your question. The answer is that your DNA “results” are merely a comparison of what your DNA looks like compared to modern sample groups from various regions of the world. So, for example, if a substantial enough portion of my DNA looks most similar to the average DNA results found in a sample of 5,000 Scottish people, the test will say that I am Scottish. The strength of that match will determine the percentage. Is it strong enough to suggest a 40% match or only strong enough to show a 2% match?
Take, for example, my DNA results. I am predominantly of British/Northern European *recent* ancestry, but know that I have one black ancestor who was an escaped slave that married a white woman. I am 3% “West African,” my dad is 6%, my grandpa shows about 10%, and so on. This ancestor in question was born in 1776 and was my 6th great grandfather. The DNA he passed on to me has progressively been “diluted” by the addition of all of my other grandparents since then; that is, the lines of all 256 of our 6th great grandparents (which, barring any inbreeding, all people will have (but see also: pedigree collapse over time)).
In my example, this black ancestor may have Arabic ancestors from 500 years prior to when he was born. But say 23andme had a time machine and could go back and give my black 6th great grandfather a DNA test. If we assume he had one Arabic ancestor from 500 years prior (around the time Islam was solidifying its influence in West Africa), you might find that his results show only 100% West African, assuming that all of his other ancestors had no Arabic DNA (which is unlikely, but just for the sake of our example). That is, the “Arab” in him is not “traceable” amidst the backdrop of all of the other noise in his genetic pedigree, most of which still came from West Africa in recent history.
All of this to illustrate, you may show up as mostly black in your results, but there is every chance that you have all sorts of non-African ancestors. Just as an example, you could illustrate the same concept with a Northern European. If you go back 2000 years in that person’s bloodline, it’s almost 100% certain they have Nordic ancestors, Roman ancestors, Slavic ancestors, Middle Eastern ancestors, African ancestors, etc. All it takes is one branch on your family tree to mean that you likely have millions of ancestors from other parts of the world stemming back hundreds of thousands of years.
In the end, this is why only your recent ancestry really “means” anything (and even then, the “meaning” is contrived at best). “Heritage” is a better measure of where someone “came” from, and your DNA is only part of that story.
This is why Nazi concepts of an Aryan “master race” and other race-based superiority complexes are ludicrous. It’s simple math. Who you “are” in a genetic sense is ridiculously complicated, because we are an amalgamation of many hundreds of thousands of bloodlines that are not all from one place, race, or nationality.
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