You have thousands of matches, but where should you start as far as looking at them? How do you
know which ones are going to be the ones that you're going to be able to find out are actually
related to you? Well, I'm going to show you a tool that might be able to help you out. Howdy,
I'm Andy with Family History Fanatics, and this is a segment of DNA. Be sure to subscribe to our
Channel and click on that bell if you'd like to be notified about upcoming episodes. You may have
heard of triangulation in relation to genealogy or DNA and are wondering what does that mean?
Triangulation is a way that we can group a set of matches and know that they are related through
a common ancestor. Now, if you know a group of people is related through the same common ancestor
and maybe you know a little bit about how some of them are related, then you can focus your research
on those direct lines as opposed to trying to look at all of your different lines of where they might
fit in. So simply match A has to match match B, and then match B has to match match C, and
then match C has to match match A. Now, these are three different matches, at least three different
matches they all match each other, but this is not enough. The most important part of triangulation
is that all three of these have to match each other on the same segment. If they match on
different segments on different chromosomes, then the group's not triangulated. You still
may be related to a common ancestor through them, but that's not a triangulated group if they match
different segments on the same chromosome. And maybe those segments are adjacent to each other
it's still not a triangulated group. You still may have a common ancestor with all those people, but
it's not a triangulated group. But when you have this same segment that is matched by everybody in
that group, then that segment was passed down by a common ancestor. What you've basically formed here
is you form this triangle where everybody is equal to everybody else hence the name triangulation.
Now I started off with just three people, but you can have a triangulated group with multiple
people, five, six, ten, twenty people. The key is is that everybody has to match everybody else.
It's not good enough that you match all of them. Everybody has to match everybody else. In most
cases, triangulation indicates that you share a common ancestor because that segment that you
all share together had to have been passed down from preceding generations. Now there are a few
special cases where a triangulated group doesn't share a common ancestor, but those are really
rare. So from your match list, if you can start creating triangulation groups, then you're going
to be well on your way to actually identifying common ancestors you share with those particular
matches. Now in GEDmatch Tier 1, there is a tool that you can use to help speed up this process.
There's ways to do this manually, and I've shown some of those before on the YouTube channel, but
the GEDmatch Tier 1 tool speeds up this process greatly for you. I've logged into my GEDmatch
account, and as I scroll down, you're going to be able to see the different tools. Now the free
tools are in DNA applications, and that's not the one we're going to use. There is a way that
you can do triangulation using these free tools. It takes a lot more time and a lot more effort,
but the one that we want to look at is down in the Tier 1. And it is called triangulation. Now
on the triangulation page, there's going to be some information that you have to enter in. So
first off, you have to enter in a kit number. So I'm going to put in one of my kit numbers. Next
is what is the maximum number of clothes match is that you want to look? at now, you should
have an idea on your match list of how much DNA you share out to you know how many matches. So,
for instance, if you have a lot of people that share a lot of DNA, let's say 20 or 30 or 40
centimorgans or more, and it is in the hundreds. Or maybe even in a thousand or a couple thousand.
Then you might want to go with a higher number for people who don't have that many closely
shared matches. Then you probably want to stick with the default of 500. The more that you go,
the longer it's going to take, but you might have more triangulation groups that are created
from that. The next thing is the upper segment threshold limit. This is the people that you want
to exclude really from your triangulation groups. For instance, right now, it is set as a default
at three thousand, which means that everybody except for my parents and my twins are going to
be included in this analysis. Now why you might not want to do this is because your siblings are
going to be included. Now you share a lot of DNA with your siblings, and because you both
have that common parent, there's going to be a lot of triangulation groups between you, one sibling,
and some other match. In fact, your sibling triangulation groups are going to be the vast
majority of these. So I usually like to make sure I lower this to eliminate siblings. And, in fact,
eliminate a lot of close relatives. So if I put this at 2,100, it's going to eliminate siblings,
but it's going to still have grandparents, aunts, uncles, and of course, my cousins. Now again,
I still share a lot of DNA with all of them and even with my grandparents. For instance,
if I'm doing triangulation through my grandfather. Well, it's just me and my grandfather. Technically
it is triangulation because we both got that same segment of DNA with whatever third match that
there is. However, it's not really a good check of it because it's really just between my grandfather
and that match. So I can lower this even further at 1500. I'm only gonna have a few of those aunts,
uncles, and grandparents. I like to actually lower it down to 1100 or even to 500. At 500, you've
eliminated most of your first cousins. If you're particularly looking for people on your mother's
side or your father's side, you might not want to eliminate your first cousins because that will
tell you automatically where that match is going to be, on your mother's side or your father's
side. However, it's still going to produce a lot of triangulation groups. So starting out, I'd
actually go with lower and start to build up from there. Next in line is the minimum segment length.
I usually never change this. I keep this at the 7 centimorgans as a minimum. Now, if you are part
of an endogenous population, you might want to increase that to 15 centimorgans or more. Next, we
have what chromosome you want to triangulate on? now you can do all of them, and that's going to
give you all your drew from triangulation groups, or you can do a particular chromosome. If you are
already researching something that you know may be a match that you have on a particular chromosome.
So for this, I'm just going to look at chromosome 1. It's gonna take less time to run right now, and
you can always do it as many times you want with a Tier 1 membership. I keep the build the same at
the default of build 37. Next is the different display options, and there's two options the
show the results sorted by the chromosome segments in the start position. And then show the results
sorted by the kit number. The chromosome segment in start position I like to show up both ways,
but if you want to just look at one way after you've seen it, then that's fine. Now we'll get
into cross-matching after I show you this initial search. So I've set up all of my options I'm
going to submit, and that's going to give me my triangulation list. So right now, what it's doing
is it's going through, and it's analyzing the kits. There's 500 kits that it's analyzing, and
you can see the progress on little asterisks as they appear down below. Once it's done processing,
it's going to come up with this match list. Now a couple things about this match list that's
different from others. This is a triangulated match list. So you're actually matching with two
people. So, for instance, there's going to be a kit 1, which is one person that matches you,
and there is a kit 2, which is another person that also matches you, but that kit 2 also matches kit
1. So as I go and scroll over, what is going to give me is it's going to give me the star in the
end location, how long of a segment that is, and then a little representation of where that is on
the chromosome. So you can see that there's these first few that are scattered throughout
the beginning part of the chromosome, and then it looks like I have a big chunk of people who
are all in the same part of the chromosome. Now I mentioned before that there is cross-matching. So
let's go back to cross-matching and see how that is a little bit different because right now, each
one of these lines represents one triangulated group you've just matched between the three
people. I'm going to do everything the same except this time I'm going to click on the cross-matching
box and what this is going to do is not only is it going to look at just those three people,
me and then two matches together, but whenever there is a segment that is similar to another
segment it's also going to add in that person. Let me show you what I mean by that. Now before
all of these segments were the same color. They were green because it was just looking at each
individual one. But now, as I go through, I can see that some of these are green which is clearly
just those three people are triangulated, but then there's a group that we saw before
that's all around the same segment what all those segments also triangulate with each other. So this
isn't a group of three people. This is a group of, it looks like almost 50 people altogether.
Now we can see down here at the bottom there is another segment. This little green segment right
here then it overlaps this, but it's not colored red. So it doesn't triangulate with that. We can
see that this also overlaps with this next one which is orange, and it doesn't triangulate with
that. So this is a separate group than these other ones. So using cross-matching allows you
to take your triangulated segments and then even further group those into a claw of people that
are going to share a common ancestor with you. Triangulation is a great way to help focus your
genetic genealogy research because now you have a group of people that you know have to be related
through a common ancestor, and you can communicate with those people and find out share trees and
see where your families may match up together. If you have any questions about how to use the
GEDmatch Tier 1 tool for triangulation, put it in the comments below, and I'll try to answer
it. And if you like this video be sure to give it a thumbs up and share it with all your friends.