Visual Phasing Part 3 - Assigning Segment Matches to Grandparents

Video Transcription

You started visual phasing and now you want to assign those segments. Well, today we’ll show you how

Howdy, I’m Andy Lee with Family History Phonetics, where we help you understand your DNA, climb your family tree and write the story of your ancestors along the way. This is a segment of DNA. Be sure to subscribe to our channel and click on that bell if you wanna be notified about upcoming episodes. This is the third video in a four-part series about visual phasing. Now, in the first two videos, we set up our visual phasing and we created the segments based off of the recombination points and the assignments we made to them. Today we’re ready to actually start assigning who those segments belong to. After you’ve created as many segments as you can, you’re ready to start assigning those segments. There may be some segments that haven’t been created, you haven’t assigned a color to them. We’ll go through how you can assign those colors.

As we’re going through the assignment steps, the first principle of assignment is to remember that the four colors represent four grandparents. Now I want to bring in one of the principles I talked about in the first video, and that is, is that each chromosome is separate. So one thing not to be confused is that the four colors representing the four grandparents in this chromosome don’t necessarily correlate to the next chromosome that you do. So each chromosome separate, these four colors represent four grandparents, but between chromosomes, those grandparents that are assigned to those colors, they may change. In fact, they will change. But right now we are just worried about this one chromosome. So step one is I want to go through and I want to add the megabase numbers to each one of these recombination points. Now, you can find this on GEDmatch. Let me show you where I’m on.

And this is the comparison between person A and person B. And the one that I’m looking at is chromosome number 10. So I can see that on chromosome number 10, I have a start of 1 35 6 56, which really I just need that first digit. It’s 0.1 and it goes to 93 million. So let me go and take a look at where these numbers fit in. So on GEDmatch, that was showing where it was just a half match. That 0.1 was the very start of this part right here, and the 93 million is where it ends. So it’s gonna be this point right here, which is why I’ve put that 93.6. Now I’ve gone through on AC and on BC to find where each one of these different recombination points are. Now that’s going to be important as we’re comparing with other people because all those other people may not be on GEDmatch, but we may be able to have this segment information to find out how we are matching with them.

So step two is you need to have some kids that you know your relationship. Now you don’t necessarily need to know the exact relationship, but you at least need to know which grandparent that person is related to you through. Now for this chromosome, I actually have four that I know are related through the paternal grandfather, and I have four that I know are related through the maternal grandmother. So I’m going to use those eight different cousins to compare which of these colors belong to which people. So let me start with my first match. And this is on the paternal grandfather’s side, and this person matches person A from 29.3 to 34.9. So that’s right in this area here. Now again, I don’t know which color the paternal grandfather associates with, so I’m gonna just highlight both of those chromosomes on person A. Now in person A and B, this person matches from 108.7 to 118.3.

So that’s about right here, halfway through on both of these that they match. And it goes up almost to that line probably. Now, one of the things with this is these values of where these recombination points are is they’re not always going to be exact because there’s some different things that all feed into that. So if it is close, it’s probably right at that line. In this case, I have this match that actually looks like he matches across two different recombination points. Now what I want to do is I want to take a look at that and decide, okay, what color is in common with all of those matches? And I can see that orange is the color that’s in common with all of those. And so I’m going to go over and I’m going to give me 1.4 orange. Next, let me do match number two.

Now, you can see on match number two, it matches between 1 27 to one 30, which is gonna be right in here. Now you might say, well, this could be purple or orange, except that there’s a problem here because if my paternal grandfather was orange in this case, well then he’d have to match up here and he’d also have to match down there. If he was purple, well he wouldn’t match there and he wouldn’t match there because they’re blue. So this is really a point for purple. So I’m going to go over here and give 1.4 purple. Now my third match. Now this person matches person A from 36.3 to 1 0 2 0.4. That’s a big segment. So 32.3 to 1 0 2 0.4 in this area here, and they match person B from 95.9 to 1 0 2 0.4. Well, that’s right up against this right here. And again, it looks like the common thing between those two is the color orange.

And so I’m going to give another mark for orange and we’ll make that number two. So match number four, right now it’s two looking up for orange and one for purple. Match number four matches person A between 28.7 and 34.4. Well, the 28.7 is really close to 29, so I’m actually going to guess that is that area right in there. Now again, this looks like it could be orange or it could be blue, except that if it was blue, it would match down here and here. So it would match all three of these people and it doesn’t. So this match is only for person A and the orange is what’s different between person A and person B and person C in this case. So this is gonna be another point for orange being my paternal grandfather. Now just looking at the numbers, my initial assumption here is that orange is a paternal grandfather and red is my paternal grandmother.

Now again, I say that’s my initial assumption because I still have this that I’m going to worry about. That’s gonna be in video four. But for right now, let’s label everything that’s orange as my paternal grandfather and everything that is maroon as my paternal grandmother. Now let’s look at those maternal grandmother matches and see where they line up. So match number one matches A from 11 to 56.2. So that is going to be in this area to 56. Point two is probably about halfway matches B from 24 to 56. So that’s actually right here, and it matches C from 16.9 to 56.1. So there’s a 16.9 right there to 56.1. It’s sort of nice that they all end at roughly the same spot. Now, since I’ve already labeled the orange and the maroon as my paternal grandmother and grandfather, I’m going to focus on the purple and the teal.

Now, one thing you will notice about all three of these is they all cover the teal, and for two of them it looks like they end at a recombination point where a color has to change. So in this case, I’m going to say that this is probably a good evidence of teal. Let’s go on to the next match. Match number two, they all start at 73.2 and they go to a couple of different places. So let’s just start this here for a 73.2 to 108.8 and 73.1 to 92, that’s about right there. And then 73.1 2, 108.8. Well, this is interesting because now we actually have the colors to show us. We can see when we’re looking at the teal, that B ends right at a recombination point where we know the color changes. And so this is another good evidence of teal being the right color.

Let’s go to match number three. Now, match number three, they match person A from 12.6 to 55.7. This is looking similar to what the other one was. This is from 24 to 55.8, and this is 12.6 2, 55 0.7. So this is almost like match number one for my maternal grandmother, and it again is very similar to a teal. Finally, match number four. Now this one’s a little bit interesting. We start at one 12, which is where the other one ended, if you remember. And it goes from one 12 to about 1 31 0.5. It goes from one 19 here to 1 31, and it goes from one 12 to 1 31.

And the reason why I say this is interesting because so far I’ve been looking at teal as my maternal grandmother. All four of these matches are on my maternal grandmother, but as we can see, B clearly does not have any teal there. Now, there is orange on some of these, but on person C, there is not orange all the way across because there’s some maroon right there. So this could be orange, it could be something else. We’re not really sure. We got a question of where this is, but for the most part, we can make our initial assumption. And that is is that teal is our maternal grandmother. And so we’re going to label the teal ones as a maternal grandmother and the purple ones as our maternal grandfather. Now, again, when we get to video four, we’re going to take another look at this and see whether or not it’s accurate, but we’re ready for the next step.

And, that is the step three. What we want to do is we want to use that match information to extend some of these segments. Let’s go back to match number one. Now, match number one, it ended right here and it ended right here. And the other one was actually right in the middle here. Now, these two A and B, they have these segments ending right where we know there is an end segment. And since this is what we’ve already said is gonna be a maternal grandmother match, then there’s good chance that we’re gonna be able to figure out what color one of these is. So let’s use some logic here. If we said that teal was a maternal grandmother and this person matches person A from 11 to 55, well, if the teal did not change, and if the maroon changed instead, then we would have a match actually on B from 11 to 56.1. But we don’t. What that means is this can’t be teal, it has to be purple because otherwise we’d have that match for B from 11 all the way up. So I’m just going to extend that all the way because that is between my two B points. Well, that means that the switch happened there. So this top one has to be maroon. So I can go through here and I can color that one maroon.

Well now I can use my ab match up here. It has to be the same. So it’s saying that this is maroon because those two are maroon, and it’s saying that this other one is purple. And so I’m going to color that purple. Let me clean that up. Now I can see where some of these segments are for my entire chromosome. I’ve actually got all of these segments created, and just from those eight matches, I’ve got all of those segments assigned. So again, just to reflect back on a couple of the principles is this is for just one chromosome. And just because I have maroon as my paternal grandfather on this chromosome doesn’t mean that maroon is gonna be my paternal grandfather on the next chromosome teal could be my paternal grandfather on that chromosome. Don’t get the colors confused between chromosomes. Remember, look at each chromosome separately completely separately.

And that’s why I like to work on just one chromosome at a time so that I don’t get confused in thinking that one is related to the other when they’re not. But at this point, our assignment of chromosome segments is complete, and you may think that you’re done right now, but if you do, then you’re gonna be missing the last step. So stay tuned for the fourth video in the series. So that is how we can assign those segments on our chromosome, but also how we can fill in some of those blank spaces that we have left over from creating those segments. Now, if you have any questions about how to assign segments based off of visual phasing, then put it in the comments below and I’ll try to answer it for you. And if you like this video, be sure to give it a thumbs up and share it with all your friends.