Searching for Segments on GEDmatch

Video Transcription

Segments in DNA are so good today, I’m going to give you two for just watching one video

Howdy, I’m Andy Lee with his fanatics, and this is a segment of DNA. Be sure to subscribe to our channel line. Click on that bell if you wanna be notified about upcoming episodes. DNA segments can be really useful in genealogy because they help to identify whether or not you might have a common ancestor with someone else. Now, GEDmatch has a couple of different tools that I’m gonna show you today how you can use these segments to find other people that share those segments. Now, one of these tools is a tier one tool and the other is a brand new free tool that you can use today. So over on GEDmatch, we’re gonna go look at the tier one tool first. Now this is part of the paid subscription and this is called segment search. Now this is gonna allow us to search for particular segments that we may share in common with other people.

So when we’re on the segment search screen, what we need to do is we need enter a kit number and this is going to be the kit that it’s finding all the matches for those segments of that kit. Now in this case, I’m gonna use just one of my kits. Next it’s gonna ask us what’s the maximum number of matches we want to look at. It defaults to just your 1000 closest matches, but you can go up to 10,000 matches if you want to. I’m just gonna leave it at 1000. You have the build to display and this defaults at B 37. If you want to show B 36 or B 38, you can do that. And then we have, just like with most matching, if you wanna change the thresholds, the minimum number of snips or the minimum segment size to be able to look at, then you can do that.

I usually just leave this at the defaults. The next part is what chromosomes we wanna scan. Now we can scan all of ’em by default or we can scan a particular chromosome. Today I’m gonna show you just one chromosome. I’m gonna do chromosome number one cuz it’s the longest chromosome, and I’ll come back to these other two here in a moment. But then we want to submit, and this is going to take us to the match screen. So once we get to the match screen, it’s going to take about 10, 20, maybe 30 seconds to gather all the data. And then you’ll be seeing this now right at the beginning here, it’s gonna give you a little warning that it didn’t have any mattress closer than 2100 sent to Morgan’s. So this would be siblings and parents. It would also be some of your half siblings, some of your aunts and uncles, some of your grandparents if you shared a lot of DNA with them.

And it does this just to conserve resources because that’s going to increase the total number of matches that there are. But even if you don’t have those people included, you’re still gonna get a lot of great data from this information. Now as we go down, we can look and see that we have the kit number, we have what chromosome it is, and in this case I just looked at chromosome one. We have the start and the end position. We have how much cent organs we share, how many snips. Then we have their contact information. And then there’s a little graphic over here that shows us roughly where on that chromosome it fits. Now as part of this graphic, we can see that there’s different colors. This is to get different matches together in the same general area. So for instance, when we looking at these red ones right here, if we come over to the start position, we see that hey, all those red ones start roughly in the same spot between 75 or that’s like 750,000 and 800,000, and then it switches over to orange, which jumps up to 4 million.

So there’s a definite gap in between there. And then we see that at yellow right here, while they’re starting at around 137 or 13 million is where those are. Now, that isn’t going to mean that everything is all close together. So for instance, the yellow starts at 13 million, but it goes all the way down to 30 million. In this case, this is helpful in that by color coding these we can get a rough idea of where some groups may be. So for instance, if I’m looking at a group, I can see that hey, all these reds, they all share almost the same starting point and some of ’em share the same ending point. We see this a hundred and twenty one, a hundred and twenty one, a hundred and twenty one, but if I actually look down, I can see that hey, there’s a couple of these forties that also share that 1-1. So there’s a good chance that this whole group might have some different groups of triangulation within it just because there’s so much commonality between those segments that’s shared.

And so this should be a big clue to help you know what we want to do next. Now, what do you want to do next? There’s two options really here. First off is we can download this, you click on this and you’re gonna get this information now into a CSV file, which you can put in a spreadsheet. And depending on how you organize your matches, that may be something that’s really useful to you. The other way is through the multiple kit analysis. Now, since this is a tier one tool, we can use the multiple kit analysis. And to do that, all we need to do is check certain boxes. So in this case, hey, you know what, I’m gonna check these boxes right here and I’m gonna not just check the red ones. I’m gonna check these orange ones too since I saw some commonality as far as where they were ending.

And then I can go and I can click on the multiple kit analysis and do some further work on that. Now the multiple kit analysis just takes me over to the GEDmatch visualization options. And then I have a lot of other tools that I can use to analyze all of those kits. So now that gives us our big segment list, but what if we want to narrow it down to just something really specific? That’s where a couple of these other options come in. Now I said before that we want to just look on chromosome one, but let’s say that I’ve already identified a triangulation group on chromosome one and it is between 65 million and 120 million. What I can do is I can look for the matches that just overlap that segment. Now in this case, since I’m just looking at this one segment, I might want to increase the overall matches.

So I’m gonna go from that 1000 to 10,000. So it’s going to look at my 10,000 closest matches to see who matches in this chromosome one 65 million to 120 million. So now what it’s done is it’s gone through and it’s analyzed just for the segments that overlap with this 65 million to 120 million. Now it can overlap at any amount as we’ll see in this match list. So for instance, so here we see a couple of matches that they just overlap a little bit right here in the 65 to 68 million. Now they go down to 62 million, but the overlap is really just a really tiny part of that, whereas others, like these first two right here, they overlap between 20 30 million and 120 million. So they actually cover a very large range of that from 65 million to 120 million. And really it’s anywhere within that. If there is any part of a matching segment that falls within that 65 to 120 million range, then it’s gonna show up on here.

So, you can see that this list is a much shorter list, but I have the same functionality that I can download that as a CSV file or if I want to do the multi kit analysis, then I can check some of those and go to the multi kit analysis to analyze them in some different ways. So that is the first tool, the tier one segment search. It allows you to see which segments you match with your matches rather than just seeing that you match somebody. And that can help you to group together, which matches you want to look at as a group as opposed to just looking at an entire match list. Now if you don’t have tier one, there’s a way that you can do something similar but also a little bit more focused. This is a new feature that showed up just in the last couple of weeks, and it is called Ancestor Projects.

It’s right down there at the bottom. Now this is going to be able to do something similar, but you have to be part of a project. So I’m gonna go to the page and show you what it looks like. Then also talk about what you need to do to get to be part of a project. So on the Ancestor project you’ll see that a lot of the information you enter in is the same stuff that you enter in for the segment search. So for thing, I’m gonna enter in my GEDmatch kit number, and then if I want to change the segment threshold, I can change that. I can add in what chromosome I want to look at specifically. And just like with the segment search, I can add in a lower and an upper limit as far as a position on that chromosome. I can sort it in different ways.

And then I’m going to go and get my list. Now this is the list of this project now. So what it is doing is it’s doing a subset of all of my matches. It’s only doing those that are part of this project. And so you have to have joined projects to be able to get this. And I’ll explain those projects in just a minute of why they can be so valuable. So in this case, in this project, there’s only three people that match me and I can see from the chromosome and the start and the end location. They all match me on different chromosomes in different locations. But if I wanted to do the select, I can select on the boxes and then go to the multiple kit analysis and look at those kits in some other different ways. Now, in this case, there was 29 kits in this project.

So this isn’t comparing to a whole lot of kits, depending on how big the project is. Well depend on whether or not you can get any information out of this. So let’s go back and let’s take a look at the projects. Now, if you’ve done some work with Family Tree DNA, you know that Family Tree DNA has their projects that you can join, which allows other people to see specific parts about your DNA. And usually those projects are centered around a surname or a location or a family or something like that. In this case, it’s the same way You can set up a project really based on just about anything. And it’s gonna give you a list of the available projects right now. And again, this is really new just within the last couple of weeks in August of 2019. So if you’re looking at this video a year or two years from now, there might be lots more projects to join, but there’ll be the name of the project, there’ll be a description, and then there’ll be an email contact or some other way of contacting the administrator of that project.

So you can go through and you can see some of the different things that people are looking at. And down here at the bottom it gives you some information on if you want to set a project, what do you need? So if you want to set up a project, then what you need is you need at least 20 kits, and that can be your own family’s kits maybe that you manage. It can also be any of your matches maybe that you’ve identified that you want them to all be part of the project. And what you’re going to do is you’re going to arrange those in a spreadsheet and send that information to GEDmatch. And then they will review over that, get that project set up, and identify who the project administrators are and have your project listed on here. And so then in the future, if you have other people that want to join that project, then they’ll be able to join that project and be able to add their DNA to it.

Now the idea behind this is you want to have people on a project who have some common DNA. So you’re sharing either some particular ancestor or maybe you’re all from some particular part of the world but anything that might have an idea of how you share DNA. And like I said, since this is a brand new feature, there’s not that many projects right now, but I’m hoping that as time goes on, we’re going to see a lot more projects that people may want to be able to be a part of. So that is two tools that you can use to search for segments on GEDMatch. Now, segment searching is really good because from that you can go onto triangulation and seeing how you are related to certain common ancestors. And it really helps to organize your work in identifying the people that are likely related to the same common ancestors. So if you have any questions about segment search or about the ancestor projects, put it in the comments below and I’ll try to answer it for you. And if you’ll like this video, be sure to give it a thumbs up and share it with all your friends.