If you ever commit a serious crime, murder or so, you will have to be very cautious with the traces you leave.
And they will get your relatives easily if they commit a crime. Which may be good or bad, depending on your relatives. I know what I think of most of mine
The 23andMe results are much more subjective than they’re presented, and recombination doesn’t make that any less confusing. For example, my mom’s always told us she has a Native American ancestor; my results show no NA whatsoever while my (same parents) brother’s show 4% NA. If we relied on my results alone we’d say that eliminates a Cherokee ancestor but w/ my brother’s results we can’t.
The sole exact number my brother and I share is our Neanderthal comparison; greater than 74% of the tested population. I wonder which explains my lactose intolerance?
You’re part centaur.
Someone please correct me if I’m wildly wrong, but from what I’ve understood reading about this is that your DNA is like a novel, but the DNA testing companies can’t read the absolute whole thing, and have to make educated guesses on what they can’t read. If someone was reading Jane Eyre and there were chunks missing, they might be able to accurately summarize the story or they might get major things wrong depending on what chunks of the book they are missing.
And this also explains why different DNA companies could give you different results, or why close relatives could get results that are more different than expected, because the company is looking at different parts of the book.
Even identical twins who were thought to have the same exact DNA have been proven they don’t. https://www.biotechniques.com/omics/not-so-identical-twins/
Great thread title / username combo!
Looking at your percentages, I see a microcosm of World War I (Western Front, at least)
That’s a bit of a strained analogy. In the case of ancestry, I’d say it’s less trying to summarize the story, than trying to identify the book. Your DNA is a whole jumble of shredded pages. The different companies have different methods and libraries they are matching it to. One comes back and says we think your jumble is a mashup of Jane Eyre with War and Peace. The other company comes back and reports War and Peace, but they don’t have Jane Eyre in their library, so they say it sort of kinda looks like Wuthering Heights to them, and your all, that’s not even the right sister.
Take it one step further, different tissue in your body don’t have the same DNA. For example, sequencing cancer cells and non-cancerous cells can reveal what mutations might be causing the cancer. That’s all super interesting, but is way zoomed in too far for discussing ancestry. To use another strained analogy, it is like telling somebody how to get to your house, and saying that Google Maps shows your driveway 6 inches north of where it actually is located. It’s not going to make a bit of difference for the direction finding use case, but if the surveyor gets your driveway off by 6 inches, that might be a big deal.
We had the same issue wrt family history and lore. My dad, for instance, expected our results to show Greek ancestry since one of our family stories is about a Greek ancestor who was trying to come to the US and ended up in Mexico. When we did the test, however, there was zero Greek. What there was that was unexpected, was some Southern Italian. My WAG was that the ‘Greek’ ancestor (assuming such a person existed) was either of Italian stock that colonized Greece sometime in the past or was actually from Italy (which would be pretty much the same thing for most Mexicans in the 1800’s).
Most of the rest of my results made sense. Lots of Native American, some German/French (both of who were heavily in Mexico at various times), and of course Iberian from the Spanish (though happily, when my 2.0 results came out it turns out they were Portuguese) and then some Eastern European/Russian from my mother’s side. The most exotic thing I had was some Turkish/ME blood and, off the wall and out of now where, 2% from India (gods know where THAT came from). Mainly the results were what we thought, but my dad was seriously bummed about the Greek thing. I think I’ve been able to explain that away with the whole Roman Empire colonized Greece in the past part, but it was definitely a discontinuity. Not surprising since, unlike seemingly a lot of Americans (or Europeans), we don’t actually know much more than oral family history for my dad’s side of the family.
Scientifically there is no such thing as an “Italian” or “Greek” gene. Italy and Greece are close enough that it is actually more likely that the DNA service you used simply didn’t have a reference population from Greece with those markers.
While the general public’s response to ancestry testing has been enthusiastic, scientists response is barely luke warm. Most of the data behind these ancestry assignments are proprietary, in this study 92% of the alleles were found in more than one region and half were found in all 7 regions they tested.
From a scientific biological perspective separate racial or ethnic groups do not actually exist. Even when they find region-specific alleles they typically only occur in a tiny fraction of that population. For heritage genetics is simply a field of probabilities and not of hard facts. It can tell you where other people who happen to share an allele were from. With that information you an infer that others may be from the same area, but is unable to say your father has “zero Greek”.
In sociology an ethnic group is a group of people who share a common heritage, culture, and/or language. In the U.S., ethnicity is often used to refer to race.
Heritage, culture, language and even “race” are not based on biology or passed via DNA. DNA can be a useful tool for inferring a connection with these groups but is is not hard evidence for or against connections.
I want to be clear that I am not suggesting that DNA can’t be a useful tool, but in cases like yours it is extremely important to remember the limitations of this method.
While it is a bummer, for heritage, DNA can provide hints but it will not provide answers without additional reliable evidence.
And Ancestry (which is the service we used instead of 23 and me) discussed a lot of what you are saying, once you dig in past the dashboard. And, intellectually, I get it. But to my family, they are looking at the pretty colors and percentages on a world map, and the colors on said map had no Greek, but instead had Southern Italian. Since a lot of the other results are in line with their expectations (i.e. we knew we had a lot of Native American and that it was from the South West…and that’s exactly what we saw, South West US and Northern Mexico and partially into Central Mexico), it tends to reinforce that there is something to this to someone who doesn’t have a clear idea of even what a gene is. It also makes explaining things like why the results might not conform to family history…challenging.
Personally, I found the results interesting, but a lot of my family was much more into it since, as I noted, so little of our own actual family history outside of oral stories is known. Literally going back beyond my own grandmother on my fathers side is like pre-history, as it’s only some stories with zero evidence, so something like DNA at least gives something to folks like that.
I have to say that, on my mothers side, the results are pretty much what is documented, so while it might not be scientific, it conforms pretty well to the records we have…i.e. part of my mothers family comes from Eastern Europe, and that’s basically what Ancestry said as well.
Saying that race and ethnic groups don’t exist is a bit of an oversimplification. What I would say is the more complex statement that in humans there is genetic variation in which there are clusters of similarity. People can be grouped by these similarities. At a very narrow level, these similarities will identify first and second degree relatives. At a much broader level these similarities can identify groups with similar ancestry. Among scientists, these ancestry groups are often referred to as “races,” but the mapping of these genetically determined racial groups to traditional racial groups is poor at best.
For example, an African American may actually have 70% European genetic ancestry, but out in the world will be called “black” just the same as a person with 100% African genetic ancestry.
And when we do genetic studies, we usually use principal components, which is a statistical test that converts the similarity in DNA between subjects into values. The values that individuals get on a particular component will cluster in relation to genetic ancestry. This doesn’t give clean answers, and experience and rules of thumb go into much of the determination of where to draw lines separating clusters. Depending on the analysis being done, it might be appropriate to do the analysis separately for different clusters, or it might only be necessary to take into account subjects’ principal components scores as part of the analysis. The problem is, that there are many pitfalls in genetic analyses if the clustering of similarity—racial groups—is ignored.
*I’m saying all of that with my genetics researcher hat on, and mean it all in as connotation free way as possible from **a white privileged hetero cis male seat. I’m not in any way trying to minimize the damage that has been caused by racism and prejudice. I can deny that culturally assigned race is a good reason to hate people, and at the same time accept that there are observable and important differences between groups of people.
*
Feel free to point me to a cite showing a scientific biological basis for race and ethnic groups and that is based on DNA. Note I am not talking about finding markers and estimating the probability that someone may match a data-set, but that there are actual genetic delineations and not just fuzzy associations with convenient correlations.
Plus I never said that race and ethnic groups don’t exist, they are social constructs but so is money. The effects of these social constructs are very very real.
I know this is IMHO, but to help people out who may be interested in this:
Here is a cite on where this does matter, but it will never be “Greek or Italian” which are useless labels
Note this quote from that paper that directly related to the issues posters have communicated in this thread.
I’m not quite sure what you are asking. What is the difference between a genetic delineation and a fuzzy association? These things are all probabilities. Sometimes it is an easy call, lots of people sort into very distinct clusters. Other times it is much harder, what about the edges where clusters overlap? If you want strict rules and determinism, then stay away from genetics, and probably all of biology.
There are differences in DNA between people. These differences are not completely random. People with more similar ancestry will probably have more similar DNA, and people with more similar DNA will probably have more similar ancestry. For better or worse, we in the field call those groups races and ethnic groups. Maybe that doesn’t meet your definition of a biological race, but that is the term used.
You asks for cites, but that is a bit nonsensical. Show me a genetic study that doesn’t mention race and ethnicity and I’ll show you something that should never have been published (and yes, they exist).
Any groups who are reproductively isolated by mountains, oceans, distance, culture, or whatever will become genetically distinct over time. They are still all humans and can interbreed with other groups given the opportunity (and will). So these reproductively isolated groups will all be living in a similar region, where maybe they share a language, culture, and other things. So all of the sudden we have a social construct—this group of people who share a language and culture. Through random genetic drift, a founder effect, or whatever, they also share some DNA. Now we have a pattern of DNA that maps on to a social construct.
There are also lots of people who are a mixture of different groups. The term we use is admixture. Most people who identify as African American are a mix of African and European genetic backgrounds. Most people who identify as Hispanic/Latino are varying mixtures of European, Native American, and African genetic backgrounds.
All of this shows the wonderful complexity and diversity of humanity.
“If we relied on my results alone we’d say that eliminates a Cherokee ancestor”. If you said that you’d be wrong, even if the test was absolutely accurate down to single digit percentages. At that distance it is entirely possible to have 0% DNA from a specific ancestor, so a test can confirm, but eliminate, ancestry.
If we stick to the novel analogy everyone has a copy of Jane Eyre, a really long one, 3 billion letters. There are 10 million known typos with varying frequencies and DNA-tests look at 500k to 1 million of these, but not necessarily the same, although the overlap between all, except the most recent 23andMe*, is way above 50%.
The different results between companies are more about it being unscientific to pick people today with a few generations of ancestry in a region and assume they are particularly representative of the population going back centuries. If we could test everyone in, say 1500, there would probably be more clumping than we see today, but there’d be clumps within national borders and there would be clumps spanning borders. The population today isn’t the result of perfect mixing of these clumps within national borders or “ethnicities”, and I was just picking 1500 as a random point anyway.
To take one concrete example. Ancestry “updated” their estimates to split up Scandinavian to Norwegian and Swedish. It is reasonable to assume that there’s a continuum of variation in Norway and Sweden, with the far West and South of Norway being the most different from the far East and South of Sweden, the southern border region having more of a mix, and the far north having a mix as well, but different, with a heavy element of Sami and Finn.
So when Ancestry slaps the label Norwegian or Swedish on these bits of DNA, what does that actually mean? It certainly doesn’t mean “that Norwegian” DNA can’t have existed entirely within the Swedish borders for many generations.
You seem to be fixated on the labels for some odd reason, as if you think most folks on this board don’t get the whole race thing. Since you seem fixated on it, I’ll clarify (again) that the Ancestry results gave broad regions of people, and my particular results as with most of my immediate family gave southern Italy as the region of origin for some of our ancestors (about 9%), but didn’t label us ‘Greek’ or ‘Italian’. There was, of course, several regions in, you know, Greece, that we apparently didn’t have any percentage of ancestry from.
Now, if you want to make the case that the regional indicators are complete bullshit, feel free to do so. I’m all ears as I don’t pretend to be even well versed on this sort of thing. But if you want to go on and on about the labels I put on things for convenience because folks will understand those labels as broad indicators of regional populations then you are basically just picking nits for your own pleasure.
Does human genetic variation form clusters or clines? echoreply points out, I think, that the distinction between clusters and clines is fuzzy; and that Principal component analysis is the way forward. For visualization it’s common to plot the 2 or 3 highest variance components on a diagram like this one. African Americans and Native Americans are definitely in different ‘clusters,’ but the distinction between East Asians and Native Americans might be more like a ‘cline.’
It might be interesting to compare that diagram with one for a species with an accepted division into distinct subspecies.
Here’s a paper discussing and diagramming genetic diversity among species and subspecies of great apes. It might be an interesting paper; I’ve not waded through it.
Here is a good page related to this, the potential for psychological, social, and political harm is high without realizing the limitations.
Regional indicators are complete bullshit with any length of time even going back to the 17th or 18th century. The number individuals who could have contributed to your genetics is so large and their possible genetic contribution so small (0.098% for 10 generations back), it is useless for any claims about who they were in person.
Regional indicators have some use for a snapshot of a population at one point in time but outside of selling services to consumers their value is minimal from a scientific point of view related to “heritage” which isn’t even a genetic trait.