Setting The Record Straight: DNA, Percentages, And Ancestral Origins

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Everyone, at some point, is tempted to do a DNA ancestry test. And there are a few reputable companies out there that will sell them to you for next to nothing. In many cases, waiting to buy a DNA ancestry kit around the holidays can prove helpful to your wallet and a few questions you have about yourself, your family, and your ancestral roots. But in the midst of that are individuals who seek to show that DNA kits are selling you something that isn’t true.

This is what I discovered when watching a video from CBC News titled, “Twins get ‘mystifying’ DNA ancestry test results” on YouTube. The video, dating back to early 2019, shows two identical twins. They’re told that, since their DNA is exactly the same, they should get identical results when it comes to their ancestral origins. To be sure, there are some results they get that are identical. But the twins highlight the results that show some remarkable contrasts, and these results are used to argue that ancestral origins is a matter of “recreational science.” In other words, “don’t take it seriously,” DNA ancestry critics say.

But is it true? I want to answer this question by responding to some of the things in the video that I think are being interpreted in a negative way without providing a full picture of the issues at hand. You’ll understand why it all needs explanation when you read the full scoop below.

So, let’s get to it.

Different companies, different percentages and breakdowns; why is this the case?

The Agro twins (their last name being Agro, I assume) perform 5 DNA ancestry tests, send off the results, and anxiously await their results online. When they get them, there are a few differences that make them question the results. First, Charlsie Agro, one of the twins, notices that she has “13% Middle Eastern” from her Family Tree DNA test. She didn’t get that in her Ancestry.com DNA test results. There was also some Iberian in the Family Tree test. They also test MyHeritage DNA, which says that Charlsie is 60.7% Balkan and only 3.4% Italian. It also says that she’s 3.8% Middle Eastern, though, so that still remains.

DNA companies analyze “few” DNA markers

The twins point out with the help of a population geneticist from McGill University in Montreal, Canada that DNA contains 3 billion parts but that DNA companies look at “less than 1% of those” 3 billion parts. In other words, there are 700,000 sections or DNA markers DNA companies analyze when processing your DNA.

Why do they mention this? Because they assume that you believe all of your DNA is being analyzed. The reality is that all your DNA is not being analyzed because most of your DNA is the same. Human DNA is 99.9% identical to each other. That explains why biblically, all of humanity comes from Adam and Eve. Yes, DNA is proof that the Bible’s claim that all of humanity comes from one man is true.

So, why do companies analyze less than 1% of your DNA markers? Because, whereas humans possess 99.9% of the same DNA, only 0.1% of all human DNA is different. It is the differences DNA companies want to look at because those differences explain why someone’s family is heavily German while someone else’s family is heavily Irish or Scottish and so on. To find the difference in origins, one must go where the differences lie: that is, in the 0.1% of all human DNA.

You and I would learn nothing much about our roots if DNA companies only examined the 99.9% of DNA that is the same!

DNA is comparative

This may be a shock, but brace yourself: DNA is comparative. What this means is that no geneticist can look at your DNA and say, “based on the color strand I’m looking at, Sally is Italian!” Instead, Sally’s DNA can only be “interpreted” as Italian in comparison with the DNA of others in the same database. The reason for this is because DNA, by nature, is comparative.

But DNA is not different from many other things in our world. Take night, for example. How do you know when it’s night outside? Sure, you see the moon and the stars in the sky, but you only know it’s night because there’s “daytime” to compare it to. Daytime brings the sun and clouds, and night brings the moon and stars.

How do you know that someone’s eye color is green? You know it’s green because of the color green on the color scale. But how did that color become “green”? The color comes from an ancient Greek word that means “grass” and “grow.” And yet, the color green is only known by its contrast to the color red, for example (or blue or some other color). We know green because it is “not blue,” for example.

How about physical features? We may not be able to look at a man and say “he’s 6-feet tall,” but we can tell that he’s “tall” as opposed to being “short.” Again, these are comparative terms, and comparisons are effective in us understanding our world. Without comparisons, such as “male versus female,” we wouldn’t be able to understand a number of things.

When it comes to DNA, DNA must be compared to that of other humans to determine just how you stand out. Remember, we’re looking at the 0.1% of your DNA that separates you from someone else because you’re unique. We’re not all exactly the same, and even biological twins have some interesting differences.

Your DNA is comparative and not self-defining.

Determining your DNA origins is “a statistical guess”

Since DNA is comparative and not self-defining, it also must be said that determining the percentages of your ancestral origins is “a statistical guess.” Based on certain algorithms and mathematical computations, software systems can determine certain percentages. So, for example, your 42% Irish ancestry is based on a computer algorithm and the percentage of DNA markers in a DNA company’s database. If your DNA marker matches up with so many other DNA markers, and genetics research tells a company that your DNA is so much Irish, then a DNA company declares it “Irish.”

How do DNA companies determine if your DNA is Irish versus Italian, or Welsh versus English? The answer to this, my friends, is a mystery. We simply don’t know. But there are ways for us to determine our ancestry without prying through this mysterious process. We can trust Ancestry (the company) and its analysis without presuming the company is deceiving us or committing a “sleight of hand” when it comes to telling us where we come from.

This means that there’s some guesswork involved in the analysis. The DNA doesn’t inherently say that you’re 42% Irish or 50% Welsh, for example. That’s a little mystery work done by DNA companies. But, when a company like Ancestry has 16 million+ DNA samples in its database, you can rest assured it knows its stuff when it comes to your Irish declaration. “It’s not a 100% sure thing,” the population geneticist says in the CBC video. It isn’t. But paternity tests are only 99.99999% sure. Nothing in life is 100%, absolutely accurate, a lofty level that nothing on earth can reach.

So if the lack of absolute certainty discourages you in DNA determinations, it will exclude you from the rest of life itself because nothing in life is guaranteed and so accurate that it doesn’t have some small or slight risk or error. There’s always a margin of error. Does that make DNA analysis phony or fraudulent? Of course not.

DNA ancestry commercials

Ancestry.com has its own commercials to entice TV viewers to purchase DNA ancestry kits. In one case, Kyle believed he was German but then, after doing his Ancestry DNA test, discovered he was 52% Irish and Scottish. “So, I traded in my lederhosen for a kilt,” he says, showing his identification with his newfound discovery from his ancestry results. One professor says that your DNA doesn’t determine if you want to wear lederhosen or a kilt. But, many of us know that. DNA doesn’t determine what you like to wear. DNA doesn’t tell us that. It tells us about our ancestral origins, to be sure. And in the commercial, the lederhosen/kilt discussion is a byproduct of Kyle discovering his Irish and Scottish heritage. It’s his heritage that made him want to dress to identify with his ancestral roots.

This same professor says that these DNA companies are selling consumers a story that “isn’t supported by the science.” 23andme’s commercial¬†mentions you can discover “your percentages of DNA,” which the professor says is “misleading.” And yet, “percentages” imply probability, right? And probability implies likelihood. And likelihood means “maybe,” not absolute accuracy, right? Well then, how are companies misleading? Perhaps “percentages of your DNA” is an inaccurate statement because these DNA tests cannot tell you what percentages of your DNA are anything.

Since determining one nationality in DNA from another is a matter of comparing your DNA to someone else, there’s no absolute certainty there. As I’ve said above, DNA is comparative, which means that your DNA is compared with someone else’s DNA to arrive at a conclusion about how much Irish or Native American you are (examples). And there’s also the declaration of whether DNA is to be labeled Irish or Welsh or anything else, depending upon mysterious guesswork of the DNA companies themselves.

DNA companies admit to best guesses and “unassigned” DNA

The company Living DNA says in the fine print of its results:

“Here we highlight the sources of your ancestry, which are likely to be present, using our best-guess of the exact source. Ancestry that cannot be attributed to one of our reference populations is shown as being unassigned!”

First, the word “best-guess” obviously reveals that there’s some guesswork involved. There has to be, since your actual DNA isn’t self-defining. Next, there is a thing called “unassigned” DNA, and it has to do with the reference populations of ancestry DNA companies.

Remember, DNA is comparative. How are your origins determined? DNA companies compare your DNA markers to those of other humans to find similarities and differences. So, with that said, companies do this by using reference populations. These reference populations consist of people that have traced their ancestry back to their earliest beginnings and “know” their history. How these individuals have done this is anyone’s guess, but these people appear to be experts on their origins. They are used to determine how to analyze your DNA based on what they believe your origins could be. There’s guesswork involved, since DNA companies don’t reveal all the details behind your analyses and how they arrive at them. And yet, the guesswork doesn’t undermine the legitimacy of the work. Guesswork can be educated, informed, and accurate.

There’s more to say in Part 2 of this post. For now, you can check out the identical twin DNA ancestry test results below.

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