DNA has unlocked links to thousands of matches. But are
you related to all of them?
Howdy, I'm Andy Lee with Family History Fanatics and this is a
segment of DNA. Be sure to subscribe to our channel and
click on the bell if you want to be notified about
upcoming episodes. Now that you've tested and checked out
your ethnicity results, it's time to take a look at all of
those DNA matches. These are the people who have also tested
that we share some segment of our DNA with. If you have a
small extended family, you may be surprised that you share DNA
with so many people but are you related to all of them? I hate
to pull a Bill Clinton here but it depends on what you mean by
related To begin, the simple answer is yes because all
humans are related. Through DNA, we can actually see that
everyone, all humans, are related to YDNA atom and
mitochondrial eve. To individuals who lived at
separate times in East Africa, about 1100, 000 to 200000 years
ago. More than 99 percent of your DNA is the same with
everyone else. But that's probably not the answer you're
looking for. Saying somebody is your 5, 000th cousin 250 times
removed doesn't imply a really close relationship next let's
look at a genealogical time scale this is where there are
records that might be able to corroborate a relationship that
is suggested by your DNA. Now this really depends on where
you're from. In Europe where almost all of my lineages can
be traced back to there are records that are reliable back
to about one thousand CE. However the vast majority of
those lineages really can only trace our records back to about
1, 600 CE so let's use that as our reference point from 1600
CE to 2000 CE there are 400 years, which is about 10 to 15
generations so the question is are all of our DNA matches
related to us in the last 15 generations the short answer no
there are a couple of ways that you can have a DNA match with
some and not be related within the last 15 generations or 400
years. The first one is common population segments. There are
certain segments in certain populations that are shared by
the majority or the vast majority of members of that
population and so those segments continue to get passed
down on and on through the generations. In this case, you
may be related to these people but it's not going to be in the
last fifteen generations and so you're probably not going to be
able to corroborate that with any kind of genealogical
records. You may be 20 or thirty generations removed from
that DNA match. Now, these are usually small segments below 15
centimorgans but they can be larger. As large as 30
centimorgans in some rare instances. The second way that
you can have a DNA match and not be related to somebody is
because you have two chromosomes for each pair. That
make sense but the computer analyzing your DNA data doesn't
know that. You could have one chromosome from your father
that looks like this and you could have one chromosome from
your mother that looks like this. Now, together, you may
match somebody with a chromosome that looks like this
and you can see that it actually doesn't match either
one of your chromosomes. What it's doing is it's going
through each location and hopping back and forth between
the chromosomes. So, this is a false match. Now,
statistically, somewhere around seven centimorgans to 10
centimorgans, the number of false matches start to
outnumber the number of real matches? That is why you hear
from a lot of genetic genealogist to not worry about
matches below 7- 10 centimorgans. Those two
categories account for the majority of your matches that
are below 20 centimorgans but what about those matches that
share more than 20 centimorgans. Are you related
to all of them? The quick answer is yes. It is very
likely if you share more than 20 centimorgans other than the
cases that already talked about that you are genetically
related to them within the last 15 generations and so it's
possible depending on the genealogical records to
identify who that specific common ancestor is now if you
share 50 centimorgans or more you are definitely related to
that individual within the last ten generations so that's only
about 300 years you can check out some of my other videos
that talk about how we share DNA different relationships and
as always, if you have any questions, put it in the
comments below and we'll try to answer it. If you like this
video, be sure to give it a thumbs up and share it with
your friends.