Have you had a DNA test and it's not what you expected
because something that you thought was going to be there
was not there. Let's go over some of the reasons today.
Howdy, welcome to Family History Fanatics where we love
helping you climb your family tree and have fun along the
way. If you're new to genetic genealogy, chances are you have
lots of questions. Be sure to check out the link in the
description below that contains our free guide to the five most
common DNA questions we are asked. Usually this questions
comes up with a specific ethnic group and probably the most
common one that I have seen is about a Native American tribe
or something with Native American and that's really
because a lot of the DNA test that have happened have been by
people in the United States and there is a lot of mythology in
the United States about a ancestor being Native American.
So, let's go over some of the reasons why a specific
ethnicity result just wouldn't up after you have a DNA test.
The first thing we need to understand is the reference
population and what that reference population is. Now,
to be a part of the reference population means that you have
a family history that is from a specific region and this has
been confirmed through a paper trail. So, the problem with
this is is that means there's got to be a set of records that
really identifies your family having been in a certain
location a long period of time. Many cultures don't actually
have written records and this makes it a little bit
difficult. Now, they get around this in some ways by assuming
that certain indigenous populations have been there for
many many years, many generations but that doesn't
always account for any kind of intermixing that may have
happened during that time period. So, if we look at
Ancestry DNAs reference population, they give a some
facts about it. There's more than 44, 000 samples in that
reference population. Now, that is still only about. 2% of all
of their DNA database. They have about 20 million samples
in their DNA database. So, it's not necessarily a very large
part of it but this is again what everything's being
compared to so it doesn't necessarily need to be as large
as the database. They divide this up into regions. Now, the
population with the most samples of those 70 regions is
actually indigenous Puerto Ricans with $4, 791 and in
fact, there are several places in the Caribbean that have a
few thousand samples in their populations. Uh indigenous
Cubans is another one as well as some others. Now, this is
because there were some studies done on these indigenous
populations in particular where a large of DNA samples were
taken from them. So, to give you an idea, Puerto Rico as a
whole is a population of about 3 and1/ 2 million but from the
data that I gathered, the indigenous population of Puerto
Rico only constitutes about 30 or 40, 000 So having 4, 700
plus samples in the database is really more than 10% of that
indigenous population which means that's going to be very
representative of what the overall population looks like.
On the other hand, the least number of samples in a
population in the Ancestry database is the which is a
group in Pakistan. Now, there's about 80 or 90, 000 that are
considered part of this ethnic group and only 23 samples for
this overall population. It's interesting first off that the
population with the most still is only a population about 40,
000 people and the population of the least is about 80, 000
people when you actually compare that to some other
population so for instance Russia and Eastern Europe
there's about 1, 000 samples in the Ancestry database to
represent Russia and Eastern Europe and yet that covers
about 200 million people so even though there's quite a bit
as far as a sample compared to many of the other groups and
regions in the Ancestry database because population is
just so large and so massive it's probably not very
representative another instance of that is the populations in
China or India where there may be a few hundred samples for
that but the populations that they're covering are 20300
maybe even 400 million people that are supposed to be
represented by that 250 sample depending on how big the
overall population is most of the regions don't really have
enough samples in them to really be representative of
everybody and so it's actually not surprising that as people
test they might not have something like Russian or
Scandinavian or something else that they thought they were
going to have simply because their populations of those
places are large enough that even just a few hundred samples
doesn't really cover the total variety of genetics within that
group. Now, we look at a map. It looks like in some cases,
there are really big regions. Now, part of that is the map
projection but when we start to look at the actual populations
of many of these regions, they're actually really really
small. So, for instance, if we're looking at the the top of
North America, there's one region that covers half of
Canada and all of Alaska that is really the Inuit population,
that's as small population. It is not millions of people. Um I
believe it's just a 50 to 100, 000. I'm not sure if it's even
much more than 100, 000. On the other hand once you go over to
Europe and you can see that in the British Isles there's
actually divided up into four or five different groups but
each one has several million people in each one. And then
with some place like Germany it's not that there's one
population there. It's actually that there's a half a dozen
groups that actually overlap that in several different
areas. Once we get down into Africa like Nigeria that has a
couple hundred million people doesn't have more than one
group and so this can be a problem in trying to identify
really the real genetic diversity with everything
ideally we just test everybody and be able to have that
diversity but we really can't with 7 billion people. So let's
ask the question to ourselves. Well how many different ethnic
groups could there possibly be? Now I decided well let me use
languages as a proxy for ethnic group. It's not really a
perfect one but languages develop over time and usually
with certain ethnic groups, they might have a unique
language. Some languages obviously have gotten much more
native speakers like English has what 500 million or so
native speakers. Mandarin Chinese upwards of 800 million
native speakers and some languages are more spread
throughout the world than so it's not a perfect proxy but
it's a start and there's about 7, 000 languages that are
spoken in the world today so if we did some math here and we
said we need at least 23 people from each one of these 7, 000
ethnic groups that would mean we need a reference population
database of $164, 000 now Ancestry has the largest one in
just over 44, 000. I think 23 and me's the latest information
I had is there's about twelve thousand but the majority of
Ancestry's database also happens to be this this
Caribbean Island studies where several thousand of the natives
from each one of these islands were tested and so the real
overall global reach if you take out those those Caribbean
Island studies is only about 20, 000 or so. So none of the
DNA companies are anywhere close to this minimum to
actually have spread throughout the whole world. Now on the
other hand if we actually look at the the database population
that would be needed for this we take that 164, 000 and we
divide it by the. 2% and we would need at least 82 million
in the database now Ancestry is about 20 million so they're
about one fourth of the size of the database that you would
need to even have this 164, 000 reference population to cover
all of these different ethnicity groups. But that was
the low end. Remember that was just looking at the minimums.
So let's look at the maximum. Let's take again that
indigenous Puerto Rican where we have just 4700 4791 samples
in it. Multiply that by our 7, 000 different ethnic groups
based on languages and you have a reference population. Now
again let me clarify this is not the database size. This is
just the reference population. You'd have to have a reference
population of 34 million. Right now, if you combine all of the
databases, 23 and me, Ancestry, my heritage, family tree DNA
and living DNA, we're just really over about 34 million
total samples for the total database but you would need
that many in the reference population to really have a a
good spread of the overall genetic diversity of all of
these different groups. Now, in order to have that then, we've
got to again do that math to out how big of a database
population it is and this is where it's key is only a small
percentage of people actually qualified to be in that
reference population so the database population doing the
math would need to be 16 billion with a B-16 billion
samples large which is twice the population of the world
right now in other words there's really no way we could
get to that maximum to have that spread of you people from
each one of these cultures to be representative of the
genetic diversity of that ethnicity and so that is the
reason why lots of people take a DNA test and they don't have
some ethnic result that they were expecting. Many of these
ethnic groups just don't exist. For instance, there's not a lot
of diversity in the database populations for North American
indigenous tribes. There is not a lot of diversity for places
like China and India simply because there had not been that
many people that have tested. Now, as testing grows as we
have more people particularly outside of the United States
that test and these are added to the populations, I would
expect to see that places like Northern India and Northern
China where right now, the region covers hundreds of
millions of people, it will to get divided up into smaller
regions. As the reference population for that starts to
increase. But overall I think there's always going to be some
ethnic groups or some you know specific subdivisions that just
aren't going to be represented simply because they're too
small. Not enough people are testing from them. And there's
not going to be enough information for a reference
population to actually distinguish them from everybody
else. Now if you would like to learn more about reference
populations you can watch this video up here. But if you want