Clustering is a method of looking at multiple DNA matches at one time to see how you might be
related to them, and GEDmatch now has a clustering tool. 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 the bell if
you want to be notified about upcoming episodes. Just in the last year, there have been several
clustering tools that have been developed and put on various websites. GEDmatch now has their own
clustering tool as well. And I'm going to show you some of the features of it. The first thing
to remember, though, is with their clustering tool, it is part of their tier 1 package. So you
have to be a member that you're paying the $10 a month in order to access this tool. So here
we are on the GEDmatch website, and if I scroll down to the tier 1 tools, I'm going to find the
clustering tool. It's called clusters single kit input the basic version. I click on that,
and I'm going to get to the screen of where it's gonna ask me for some input. Now what you need
in order to cluster is you need a kit number, and then you need to define what these thresholds are,
and we'll talk about the thresholds in just a second. I'm gonna leave them at the basic
thresholds initially. Genesis is now going to go through, and it's going to start gathering all the
data to create the cluster table. Now depending on what your thresholds are, depending on how
many matches you have. This could take several minutes, so just sit tight and wait. One said
match has figured out where everything is. It is now going to display the table, and initially,
it's going to show you it by the kit number. But as you can see, it's going to reorganize it
based on the average shared centimorgans for each cluster. Now again, this can take a little bit,
but it's nice to actually watch this graphic as you're seeing kits move back and forth. And you're
starting to see these clusters form, and depending on what you set your thresholds at and depending
on the matches, this table could be humongous. In this case, this is about 500 matches. If I look
across the top and if I look down the side, I'm gonna see the exact same names of these matches
that I have. Now each one of these matches match between that threshold that I've set,
but they also match other people between that threshold as well, and that's what these boxes
all indicate. Now one of the things that you can do with the clustering tool on GEDmatch is you can
actually change how this is going to be displayed. So if I look at the drop-down menu up at the top,
it's going to let me change that by the name, by the kit number, by the cluster number. What
I'm gonna do is I'm gonna change it to the cluster size. And once I change that to the cluster size,
everything's gonna reorganize based on whichever is the biggest cluster and then on down the line.
Now you can see here for this giant cluster at the beginning. They all share on average about fifteen
or sixteen centimorgans except for one person now. This is gonna be a very distant relations that all
these people have to myself. So normally, what I like to do is I like to focus on those clusters
that have the most amount of shared DNA with me, and that would be the cluster average cm to the
reference kit. So the cluster that has the most average between all the matches with the main
kit. Now on this page, there's actually a lot of information that you can access. For instance,
if you go to each one of the amount of shared centimorgans clicking on it is going to show you
the one-to-one comparison for autosomal. So you can do a one-to-one comparison with any one of
those matches. The other thing is by just clicking on the box itself. The colored box of the match
it will also go to that one to one. So there's two different ways that you can do a one-to-one
comparison really quickly between a specific match and yourself. The little eye icon is going to open
up an information box. And that information box is gonna tell you about that match their name,
the kit number, and the email that is associated with that kit. So let's talk a little bit about
thresholds. I've done just the basic thresholds, which were 15 centimorgans to 50 centimorgans.
If I go back, I can actually change that number, and changing the thresholds can have a true Matic
effect on the cluster chart. It can affect how many people are gonna be showing. It can affect
how big some of those clusters are. All because you're looking at different ranges of the amount
of shared centimorgans between all these people. So, in this case, I'm actually going to just
change this lower threshold from 15 centimorgans up to 20 centimorgans, and then I'm gonna click
on my cluster. So that's all I've done is just change that by 5 centimorgans. Now you can see
initially right off instead of 500 matches. It's only found 371 matches that meet that criteria.
So I've already decreased the total matches by 1/3 just by going up by 5 centimorgans. Now where this
could be important is for people that have a lot of endogamy in their family history. By changing
the amount of the threshold from 15 to 20, you're gonna eliminate a lot of people that may be even
more distantly related than what you want to be looking at. So now that the chart is finished,
it actually looks a little bit different. I've blocked out the names, but I can tell you right
now that these names at the top are not the same ones that were at the top before. All because of
that change in the threshold, not only that, there's actually a little bit larger cluster
right at the beginning. If I go and I look at cluster size, if you remember that we had this
really giant cluster before, that was our big cluster. Now, as I can already see, this cluster
is much smaller than what it was before. Before, people were sharing about 15 to 16 centimorgans.
I've changed that threshold up to 20 centimorgans. So it's going to be looking at people that share
more than that already. So let me go back and let me actually change the size again.
I'm gonna actually change it up to 25 this time, but I'm also going to change the upper threshold,
and in this case, I want to include some of my cousins in this, and so I'm gonna change this
up to 1,300 centimorgans. So it's not gonna be getting into my aunts and uncles and grandparents,
but it should be getting into my cousins, second cousins, and all of that. Now because I've changed
that from 25 to this 1,300. That 25 makes a big difference. You can see instead of that 371,
it's only looking at 55 kits even though I've changed that upper threshold all the way up to
1300. So just another 5 centimorgans dramatically affected how many matches I am showing. Now,
as I scroll down, I can see some of these clusters. The more centimorgans, the higher
the upper threshold for centimorgans, the more of these grey squares you're going to find. Now,
these grey squares indicate that they actually probably belong in multiple clusters. So, for
instance, these people right here not only do they belong with this orange cluster, but they also
belong down here with this purple cluster. And again, that's because we're looking at more and
more relatives that are closer related to us. So, for instance, I'm gonna share a lot more relatives
with my first cousins than I am with my second or my third cousin. So it's really important that you
play around with the thresholds to find out the information that you're trying to look for. But in
essence, what you're doing is you're categorizing people based on other people as well. So no matter
what type of clustering you do, you're going to be getting some information that may help you in your
genealogy. So one of the really tricky things with clustering is families that have endogamy. Because
there is so much shared DNA, you may end up with this huge giant cluster that covers most of your
page. Let me show you an example. Here this is a family that hasn't talked to me, and initially,
these clusters are looking ok, but then we start to see this orange cluster down here,
and as we scroll across, we can see whoa this orange cluster is covering everything. This is
all still one cluster and in actuality, when I go through this cluster is 450 people large. Now
from a genealogy standpoint, that is just way too many people to try to work with at one time, and
so from a clustering standpoint, this large of a cluster is not very useful. So what somebody with
endogamy needs to do is they need to go through, and they need to adjust their thresholds to try
to break up a club like this. Now the other thing with this is this may take a long time to load,
so for instance, this chart took about seven minutes to actually get created, and that's
just because of all these connections that we see here in this one giant cluster. Now, this is the
same family. Only what I've done is I've changed that lower threshold up to 25 centimorgans. Now
initially, what you can see is that it's broken out, and there's a lot more little clusters,
and so I've taken that great big giant when I broke it out into little ones. Although once we
get down far enough, there is going to be a really big cluster that still is the majority of it,
but it's not as much. Before it was 450 people that were in this giant cluster. Now, it's only
344 people that are in this giant cluster. So I've started to break this cluster down,
and again as you change those thresholds, you're gonna be able to start to separate out how some of
these families fit together as in which ones are most closely related together. So what
are some of the things that you can do with this information? Well, first off, if you want to save
this information, you can actually do that as an HTML file, and all you need to do is anywhere on
the page. Just do a right-click and then do a save as, and for that, you want to save it as an HTML
file. So change that to HTML. When you open it up, you can see that the page looks very similar,
and one of the nice things about that is you still have the ability to rearrange things based off of
the cluster number or the size or however you want is still going to go through that motion
of rearranging your clusters in that way. The one thing that you do lose is you'll notice is
you're gonna lose your links to do that one-to-one comparison, and you can also lose that info link,
but it still gives you most of the information that you're going to need. So if you don't do the
tier one every single month and what it is, is it's a good idea to do your clustering for your
kits, save those as HTML files, and then at least you have the basic information that you can use
later when you aren't a tier one member. Another thing that you can do is use this clustering
in conjunction with the multiple kit analysis. Now the multiple kit analysis is another tier
one tool that can be used to look at several kits in lots of different ways. I'm only going to show
you a little bit about that in this video, but I will have more videos that show how you can use
multiple kit analysis with all their different functions. So for the multiple kit analysis,
what you need is you need to select some kits that you want to analyze. It automatically selects your
base kit. So I've been selected, then I can go through, and I can select some other kits.
So let's take a look at this blue cluster right here. I can go through, and I can click on each
one of these individually. If I want to, but if it is a large cluster, that's gonna take a long
time. So what I can do instead is I can go over, and I can find the legend. And in the legend,
it's all organized, and it has the colors of those kits. So, in this case, I want this blue kit. If I
click on that, I can see it has selected all of those kits already for me. The nice thing about
this is if I want to select multiple clusters, then I can do that. Now, where would you want
to select multiple clusters? Well, if you're seeing that, there's a lot of overlaps. So,
for instance, right here, I can actually see that, hey, between this red and this blue,
there's actually this one person that overlaps. So let me select the red and the blue cluster
just to see how those people combine together. Now once I have selected the kits I want to analyze,
I go up to the multiple kit analysis. I click on the button, and I'm gonna just look at a compact
map for my segments. I'm gonna see what segments I share in common with those people. Now, remember
I had two selections. I had the blue kit, and I had the red kit. I'm gonna zoom in just a little
bit here so we can see this more. Now, these first four people were all part of the blue kit,
and you can see that we all share a segment on chromosome number 5. Now, these other people
they were part of the red kit. You can see that we share a segment all on chromosome number four,
and then, of course, there was one person that was a link between those two, and that is this Logan
Brown. Now it doesn't show me how Logan Brown matches with those, but then I could change my
primary person to Logan Brown, and I can see how Logan is related between those. Maybe Logan shares
DNA with them at another location on it, and that is a quick introduction to the clustering
tool on GEDmatch. Now clustering involves a lot of different things as far as analysis, and so in the
future, I'll have some more videos on clustering and specific cases of how clustering can be
used to solve some problems, but if you have any questions about clustering, put it in the comments
below and if you like this video be sure to give it a thumbs up and share it with all your friends.