RLP 228: The Effect of Pedigree Collapse on DNA Matching: A Case Study

Nicole (0s):
This is Research Like a Pro episode 228 The Effect of Pedigree Collapse on DNA Matching A Case Study. Welcome to Research Like a Pro a Genealogy Podcast about taking your research to the next level, hosted by Nicole Dyer and Diana Elder accredited genealogy professional. Diana and Nicole are the mother-daughter team at FamilyLocket.com and the authors of Research Like a Pro A Genealogist Guide. With Robin Wirthlin they also co-authored the companion volume, Research Like a Pro with DNA. Join Diana and Nicole as they discuss how to stay organized, make progress in their research and solve difficult cases.

Nicole (41s):
Let’s go. Hi, everyone. Welcome to Research like a Pro.

Diana (47s):
Hi. Nicole. How are you doing?

Nicole (49s):
Hi mom. I’m Doing. Great. It’s good to be here today to talk about Pedigree Collapse.

Diana (53s):
Oh great. Well I know we have a lot to cover. So let’s do our announcements and then we’ll jump right in. Registration for Research Like a Pro DNA will begin December 1st, 2022 and it will go from February 1st, 2023 to May 10th with three break weeks. So the study group will take up most of your spring if you want to join us, so plan for that. But we are excited to get going on another DNA adventure. We have our peer group leader application on our website if you’re interested in a complimentary registration for being a peer group leader. And then join our newsletter for coupons, especially with the holidays coming up.

Diana (1m 35s):
We’ll have some Black Friday sales coming up and holiday sales and you’ll want to take advantage of those for our courses. We are excited for Roots Tech. We are right now in the process of getting our syllabus material ready. Hard to believe we’re having to do that right Nicole?

Nicole (1m 50s):
Yeah, I need to get started.

Diana (1m 54s):
Yeah, so let’s talk about our topic for today. And today we’re talking about Pedigree Collapse in our dna. Such a good topic because this can really make a difference in our DNA analysis and if we are not aware of how to deal with it, it could be a real problem.

Nicole (2m 12s):
Yeah, some people just want to kind of avoid it and because it’s hard to know what to do so. Right,

Diana (2m 18s):
Right. So let’s do a definition first. Pedigree Collapse occurs in a person’s family treat. If one of their ancestral couples are related to each other, this causes the same ancestors to be repeated in their tree. For example, if a person’s parents are second cousins through their great-grandparents, Joseph Dyer and Anna Smith, then Joseph Dyer and Anna Smith appear in the test taker’s Pedigree twice. Instead of having 32 unique third great grandparents, this test taker has 28 unique third great grandparents.

Nicole (2m 51s):
So in the picture that goes along with this and the blog post I wrote about it, you can see that the ancestral couple appears twice and then, then if instead of having them in there twice, if you just have your line connecting go up to where they are in the other spot, that’s how the Pedigree collapses down because instead of having these unique people in each position in the family tree, there’s some positions in the family tree that are empty because the lines are going back to somebody else, the same person and a different spot.

Diana (3m 20s):
Right? And it leaves an empty spot where that extra set of four great grandparents should be for this example. So that’s a great illustration.

Nicole (3m 30s):
Yeah. So since we have been talking about endo, Pedigree Collapse in multiple relationships, let’s just remind everyone what the definition of these three terms are because this case study actually uses both Pedigree Collapse and multiple relationships, which is often the case when you’re working with a case like this that it doesn’t always fit neatly into one of these three definitions. You know, sometimes it’s a combination of two. So multiple relationships is different from Pedigree Collapse that occurs when you have more than one common ancestral couple with a ma a DNA match. So you’re related on more than one of your family lines. Your family tree looks normal, you don’t have the same ancestors in two positions in the tree.

Nicole (4m 12s):
But when you compare your tree with the DNA matches tree, you find that between you two you have more than one set of common ancestors who both contributed shared dna. Pedigree Collapse is a little different because it’s when in your own tree you have the same ancestors in more than one position and then Pedigree Collapse can become inmy if it repeatedly occurs over many generations. But two or three instances of Pedigree Collapse does not make endo. So the definition of inmy is when related people reproduce within the same population for hundreds of years, generations and generations. And if your ancestry is ous, you’ll have multiple distant ancestors repeated in your family tree over and over.

Nicole (4m 53s):
And so this is just like extreme severe Pedigree Collapse over a long, long, long, long time.

Diana (5m 0s):
Right. And sometimes it’s hard to know when one ends and one begins, but the important thing is just to realize it does affect how you look at the dna. And so that’s what we’re working on with this series, understanding how to use DNA with these situations in the family tree. Right. So how do you find out if a test taker has Pedigree Collapse?

Nicole (5m 21s):
Well, the best way is to look at their tree. But one way you can check to see if a DNA test acre has the same common ancestors on both their maternal and paternal sides is to use the are your parents related tool at Juma. And this is a free tool that can help you figure out if there are any runs of HOMOZYGOSITY or R O H, which indicate segments of DNA where the test taker’s parents contributed identical DNA at the same location, meaning the parents match DNA at that spot. So all you need is to have your DNA transferred over to GMA or your test taker and you can use this pre tool and it’s pretty easy to just put the kit number in the tool and then it returns results and tells you there’s no runs of homozygosity or there are some runs of Homozygosity and that just means a segment of DNA that in the tool is green, meaning that the maternal chromosome matches the paternal chromosome in that spot and it will tell you how long the segment is.

Nicole (6m 22s):
And if there’s a lot of that then the parents were related more closely. And if there’s only like a few small segments of the runs of Homozygosity, then the parents were related more distantly.

Diana (6m 32s):
But that tool is only on Gedmatch, right? So you have to upload your DNA wherever it comes from, whichever company to Juma and then use the tool there.

Nicole (6m 44s):
Right. And there’s another tool I believe at David Pike’s website.

Diana (6m 48s):
Okay, well that is an interesting thing and you might be wondering why you’d really need to use this. While we are often using test results from other people, not just ourselves, we may know our Pedigree really well, but say we ask someone to share their results with us and we want to use their DNA test results and maybe they don’t even have a tree or they don’t know their tree as well, this would be a great thing to do just right at the beginning to make sure you’re not going to be dealing with Pedigree Collapse or endo.

Nicole (7m 19s):
Yeah, exactly.

Diana (7m 19s):
So have you ever found someone with runs of Homozygosity with this tool?

Nicole (7m 25s):
I recently did and it’s a person who’s DNA match to my father-in-law on all the different sides and, and I was looking at his tree on family tree DNA and I didn’t notice the Pedigree Collapse but then when I ran the Are your parents related tool at jma, he had two short runs of Homozygosity revealing that his parents are distantly related. So once I knew that, I looked more carefully at his Pedigree and saw one of the surnames repeated in the third grade grandparent level and followed them back to see that they both descended from the same ancestral couple.

Nicole (8m 5s):
So his parents ended up being third cousins once removed and also third cousins, so they were related twice. There was also another instance of Pedigree Collapse further back on his paternal line, but it only affected the paternal side and his mother wasn’t related to that side. So he had a couple instances of Pedigree crops. And so I took his tree and I put it into the exploring family trees visualization tool@learnforeverlearn.com slash ancestors. And that is the tool you might have seen before that can visual help you visualize Pedigree Collapse and Endo mean. And it kind of shows these curved lines going back to the same ancestor when the Pedigree collapses.

Nicole (8m 49s):
So that was kind of interesting to see that. And you can look in the blog posts that accompanies this podcast to see what it looks, looks like. But if you have a jcom you can upload that to learn forever learn.com/ancestors and you can see what it looks like in your tree to have the same ancestors repeated. Yeah, in multiple positions.

Diana (9m 8s):
I really like that visual. And this is strictly on a family tree. This has nothing to do with dna. This is strictly using a jcom which is just your family tree file. Correct.

Nicole (9m 20s):
Yeah.

Diana (9m 20s):
Interesting.

Nicole (9m 21s):
Yeah, so that’s what I like about the are your parents related tool because that one is just a DNA tool. It just looks at the DNA to see if the parents have any overlapping segments, you know, in the maternal and pater chromosome Matching and that won’t catch all Pedigree Collapse because if you just have Pedigree Collapse on only one of the parents’ side, you know like your paternal grandparents married each other or something, then it won’t show up as runs a porosity with you. So you would have to test your father for that one.

Diana (9m 49s):
Okay, that’s so interesting. So how does this Pedigree Collapse affect DNA match analysis? Can you still compare expected amounts of DNA sharing with actual amounts for evidence of a relationship? You know, we’re so used to using DNA painter shared Center Morgan project tool to verify our relationships. But you know as we are learning and as we’re working it that we’re finding that Pedigree Collapse has some impact on that. So what are you finding?

Nicole (10m 17s):
You still can compare the expected amounts of DNA with the actual amounts for evidence, but it’s trickier you have to do some different things. You can’t use the Sheen Morgan project. It doesn’t work with Pedigree Collapse in Endo mean. So let’s do A Case Study showing how we can do this with Glen Hopper. The test taker for this hopper case does not have any known Pedigree Collapse in their own family tree. But then the discovery of a close DNA match who did have Pedigree Collapse on the relevant line caused additional analysis to be done. So let me tell you about this. So Glen Hopper was born in 1902. He was the son of Susan Hopper and an unknown father and family.

Nicole (10m 58s):
Laura stated that Glen’s father was Dan Daniel, a coal miner and evidence from Y DNA testing did point to the father of Glen’s surname being Daniel. However, the social security application that Glen created in his lifetime stated that his father’s name was Robert Daniel, not Dan Daniel.

Diana (11m 21s):
Oh, interesting. I wonder if that is a Welch name. I was just starting a little bit about Wells and they seem to have names like that where they have the first name and the last name be similar and they were calling

Nicole (11m 33s):
Yeah, Thomas Thomas and whatnot. Yeah. Interesting. Okay, so you have got the DNA match who has Pedigree Collapse. So that can affect anybody cuz we don’t know what our DNA matches have in their trees, Right? Yeah. We have to be very careful as we analyze the pedigrees of our matches.

Diana (11m 56s):
Okay, so you have this Y DNA evidence that showed the surname was Daniel and you’ve got these clues of Dan Aura, Robert Daniel. So what did you do to further your objective with autosomal dna? Because Y DNA you have to use along with autosomal,

Nicole (12m 13s):
Right? Those, the Daniel surname matches had a common ancestor in the 17 hundreds and this was focused in 1902. So we needed to use autosomal DNA to figure it out with more close matches. So to determine the father of Glen Hopper, whether it was Robert Daniel or some other man, the autosomal DNA results of one of Glen’s children were analyzed. A close DNA match was discovered and we will call him Joseph, which is not his real name, just for privacy. And he shared 239 cent Morgans with Glen’s child, our tester and looking at Joseph’s tree, several ancestors with the surname Hopper and Daniel jumped out and at first the most obvious set of common ancestors with Joseph was Robert Anderson Hopper and Susan Pollard on Glen’s mother’s side because we already knew Glen’s mother’s side of the tree.

Nicole (13m 3s):
Glen’s father’s side was empty with just the surname Daniel as the clue. At first we saw the common ancestor on Glen’s mother’s side and that was a third cousin once removed relationship. But according to the shared Sun Morgan project, third cousins once removed on average share 48 cent Morgans or from zero to 192, Joseph and Glen’s child shared 239 outside of that range. So that tipped us off that more relationships likely exist than just that one common ancestral couple. So looking at Joseph’s tree, we saw Robert Daniel in his tree. So that’s one of our hypotheses that Glen’s father was this Robert Daniel, could we just use that relationship and say, yep, Robert Daniel’s the father?

Diana (13m 45s):
That’d

Nicole (13m 45s):
Be easy. That would be an erroneous assumption, right? Because there’s already another relationship besides that one on the mother’s side. So no, if that hypothesis is correct, there’s already multiple relationships, right? Yeah. So Joseph’s grandmother was a daughter of Robert Daniel. So if Robert Daniel was the father of Glen, then Glen’s child and Joseph are half first cousins once removed in addition to third cousins once removed on Glen’s mother’s side.

Diana (14m 15s):
Oh it’s so confusing. If you are listening and confused, just look at the blog post and see the diagram. That’s the tricky thing. You really cannot visualize these types of multiple relationships or Pedigree Collapse without drawing diagrams. It just, you can’t wrap your head around it. But I think it’s such a good point that you made that when you start seeing these surnames pairing multiple times, that’s such a good indication that you’ve got something going on. All right, so we’ve got this hypothesis and you’ve got inflated amount of dna. What does the shared center Morgan project say about this? Because you’ve got two different relationships right going on.

Nicole (14m 57s):
Right, so like I said, for the third cousin once removed relationship that was an average of 48. But since we’re hypothesizing, there’s also a half first cousin once removed relationship. The shared Cinema Morgan project says for that that the average is 224 with a range of 62 to 4 69. So with Joseph and Glenn’s child sharing 239 cent Morgans, it seems closer to the 224 average of the half first cousin once removed. But then if you add 48 cents, which is the amount for third cousin once removed to 224, you get 272. So with multiple relationships you can use the strategy to estimate the expected amount of shared dna.

Nicole (15m 39s):
You just take the average for each relationship that you found in the two trees and you add it up. So 48 plus 224 equals 2 72. So if you’re seeing two relationships like that, you can say this is an average expected amount that you might see and say okay, well 239 is pretty similar to 2 72 but this strategy is not one you can use for Pedigree Collapse or Inmy So. It only works for multiple relationships. And after reviewing Joseph’s Pedigree further, we see that Joseph’s great-grandparents were Robert Daniel and Eda Hopper and they were first cousins who got married to each other.

Nicole (16m 20s):
So this results in Pedigree Collapse in Joseph’s tree. So his third great-grandparents Marcus Daniel and Martha Mays are in his tree twice. They’re occupying two different positions. So Joseph received extra DNA from them possibly causing him to share even more DNA with Glen’s child. If our hypothesis is correct that Robert Daniel was Glen’s father, so if Robert Daniel was Glen’s father, Glen’s child has three distinct relationship paths with Joseph.

Diana (16m 53s):
Oh wow. That is a lot. And that is tricky. I had a question for you. How did you discover all of this? Did this test taker Joseph have a good tree?

Nicole (17m 2s):
Yeah, he

Diana (17m 3s):
Did. Okay, so you were able just look at the tree and see it all?

Nicole (17m 6s):
Yep, just looking at his tree you can see all the hoppers and the Daniel people and just, okay, here we go, there’s a bunch of ’em.

Diana (17m 14s):
So you know, that is just such a good point because if you have a DNA match and they don’t have a good tree, then you have to build it or figure it out. And so we really wanna use those amounts of shared DNA from the shared center working project to tip us off that there might be something else going on. You know, cuz if there’s no tree or if it’s an unknown parentage case, you know and you’ve got something out there that you just don’t know and things aren’t adding up, it could be multiple relationships or the Pedigree Collapse. So it’s just good to be aware of this.

Nicole (17m 44s):
Well and it just reminds me of the standard about reviewing the matches pedigrees and not just focusing on, oh I built this one line out and this is where the common ancestor is. I can ignore that other side of the Pedigree that’s empty. Yeah because if we’re using that as evidence, we could be using it wrong if we don’t realize that there are other possible relationships.

Diana (18m 7s):
Oh yeah it and it also reminds me of something that we hear a lot in genetic Genealogy that the DNA doesn’t lie but the analysis can be wrong. And I think this point, so a really good example of how the analysis could really be wrong if we’re not taking into account these other relationships, right?

Nicole (18m 24s):
Yeah. If I didn’t notice all these other relationships, I might just say, oh Robert Daniel is the father of Glen Hopper because look, they share this amount that’s consistent with half first cousin one’s removed, right? So that must be it, right? All right, so with Pedigree Collapse now added in, we need a new strategy to use the match with Joseph as evidence for or against the hypothesis because we can’t just add up all these different relationships from the shared Cinema Morgan project, you know these averages because we have to kind of break it down into these distinct relationship paths.

Nicole (19m 4s):
And because our test taker doesn’t have Pedigree Collapse but our match does, that’s one really good reason why we need to break it down into distinct relationship paths. And we can’t use the shared son Morgan project because the test taker only has the ancestral couple in their tree once, but the match has the ancestral couple in their tree twice So. It would be too much DNA if we use the average from the shared son Morgan project. And so we really need to just focus on finding these distinct paths and then estimating the amount of DNA for each path and adding them up. At first we might think we could just go add up those averages and so we would get 48 cents for first cousin once removed and we would add that up twice and then we would add up 224 for half first cousin once removed and that would give us 320 cent Morgans.

Nicole (19m 53s):
But that’s not going to be a correct estimate for the expected amount of shared dna. And one issue with that method is that the shared cent Morgan project is biased to be high because some third cousins once removed won’t match at all. But people who are self-reporting their matches to the shared cent Morgan project are not likely to report that cousins don’t match cuz they’re looking at their match list and just choosing the matches that do match. Right? And so volunteers who submit data are just picking, you know, the ones that do match also the volunteers who submit data are more likely to figure out the relationship with cousins who share more DNA rather than the ones lower on their list.

Nicole (20m 34s):
Usually we start at the top of our list. So anyway, the average from the she center Morgan project is a little higher than you know like a statistical average. And so rather than adding up the averages from the shared center Morgan project, when you have Pedigree Collapse, a better option is to use the coefficient of relationship calculation. And this helps you break down each path to all the common ancestors like I was saying before.

Diana (20m 59s):
Okay, so let me just recap. If you have multiple relationships you can add up the average amounts from each relationship to get your estimate. But I thought it was really interesting what you said about the shared center Morgan project biased to be on the high end because that makes total sense. If you are sharing more DNA with those relationships further back, you’re going to report it and the ones you don’t share much with you just won’t know. So that’s such a good thing to keep in mind. So we need to use this coefficient of relationship in working with Pedigree Collapse. So tell us more about that.

Nicole (21m 33s):
Right, so that works with Pedigree Collapse, it works with Endo and it works with multiple relationships. But what doesn’t work with Pedigree Collapse and Endo is adding up the averages from the shared set of Morgan project. So that one’s not a good strategy for when you have Pedigree Collapse. So when you have Pedigree Collapse, we need to use a calculation called coefficient of relationship and this helps you estimate the expected amount of shared DNA between two people. And it’s a formula used by geneticists, it was a term coined by who write in 1922. He originally called it the coefficient of inbreeding and it ranges from zero to one with one being the most related and zero being the least related.

Nicole (22m 19s):
And so the first thing you do to use this formula is identify each individual who is a common ancestor between the two people. And so a straightforward example of this would be first cousins, they share two most recent common ancestors, their grandfather and their grandmother. And so the number of generations separating each cousin is the next thing we need to find out. And so we have cousin A and they go two steps up their tree to their shared great-grandfather, their shared grandfather, and then two steps down to cousin B for a total of four steps. And then this is repeated for the grandmother, so up cousin a’s tree to grandmother and down to cousin B.

Nicole (23m 5s):
Two more steps for four steps total. So you have two ancestors and you have four generational steps. And so what you do is you raise one half to the fourth power for grandpa and then raise one half to the fourth power again for grandma and that equals one over 16 and then you add one over 16 for grandma plus one over 16 for grandpa for a total of one over eight. So your coefficient of relationship is one over eight or 0.125. So that is the same as 12.5%. So first cousins have a coefficient of relationship of 12.5% and the equivalent of about 875 centa organs.

Nicole (23m 51s):
So that’s how you know genetic Genealogist can estimate how much DNA a person might share with their relatives.

Diana (23m 58s):
So when we see those percentages in all the different charts, that’s exactly how we have come to those numbers using the coefficient of relationship,

Nicole (24m 8s):
Right? And the reason why you’re taking one half and raising it to the power of how many generational steps is because you are assuming that the DNA is halved in each generation. So from you to your parent half and then half again. So that brings us to one fourth from a grandparent and then half again and each generational step in half.

Diana (24m 32s):
Yeah, that makes sense. And nobody told me I’d have to do math when I did Genealogy apparently, apparently with DNA we have to do math, right?

Nicole (24m 41s):
We were just maybe thinking you’d have to like subtract some years to calculate like you know, birth years easy math

Diana (24m 48s):
Have to do, it’s easy math, not this stuff. But actually it’s, it’s really nice and you’ve explained it really well in the blog post with some really good visuals, especially I think the thing that’s important to understand is just that whole idea of the steps, you know from the test taker all the way up to the common ancestor and them back down to the DNA match. And so you know, for those listening, take a look at the blog posts and check that out so you can kind of get that in your head how you get those steps. So now tell us a little bit more about breaking down the distinct relationship paths.

Nicole (25m 23s):
Okay, this is a tricky concept. So it’s important to remember that each ancestor, each person or individual in the tree is considered a separate relationship path rather than thinking of ancestral couples being grouped together in the relationship path. Because we often in genetic Genealogy think of common ancestral couples, but when calculating the coefficient of relationship we need to think of each ancestor separately. So with the hopper example, we need to list each common ancestor between Glen’s child and Joseph, including those who are in Joseph’s Pedigree twice to to put Pedigree Collapse. Then we’ll count the number of generations separating them all.

Nicole (26m 4s):
And I used a lucid chart to do this and so I mapped out all five of the relationship paths because even though I said there were three ways they’re related, there’s five relationship paths, one for the half first cousin once removed and then two for the third cousin once removed and then two more for the other third cousin once removed relationship because both of those two had two ancestors in common. So there’s five total paths to an individual in the tree. The way that I did this was using Lucidchart to kind of map each of the five paths out and then on the connecting lines, connecting each box, I added a small blue number on the line to count how many steps there were.

Nicole (26m 52s):
So for the first one, Robert Daniel, the hypothesis is that he was the father of Glen and so if he was the father then Susan was the mother. And so his wife EDA Hopper, she had a daughter named Elsie that was Joseph’s grandmother. And so there were, there was only that one common ancestor because he would’ve had two relationships if he was the father he would’ve had a relationship with Susan Hopper and then a relationship with EDA Hopper, that’s why it’s a half. Anyway, so there are five generations separating Glen’s child and Joseph. So we start with Glen’s child and we go up two steps and then we’re at Robert Daniel and then we go down three steps to Joseph and so that’s five.

Nicole (27m 37s):
So we would take one half raise to the fifth power, which is one over 32 or 0.03125. So that’s our first one. So the next relationship path is to Robert Anderson Hopper and Susan Pollard. And so Glen’s child and Joseph are third cousins once removed through these two common ancestors. So from Glen’s child up to Robert Anderson Hopper is four steps and down to Joseph is five steps since they’re in different generations for a total of nine generations of separation. And then it’s the same exact number for Susan up four and down five for a total of nine.

Nicole (28m 17s):
So we would raise one half to the ninth power, which is one over 512 and that’s the same as 0.0 0 1 9 5 3. So then you would add those two together for those two relationship paths.

Diana (28m 30s):
So I have a question here because this is not a half relationship, he’s related through this couple, you do the calculation for both the man and the wife. Yeah

Nicole (28m 41s):
Because you have to consider that both of those two individuals contributed DNA and not just you know, one of them.

Diana (28m 48s):
So, so that’s how they get the percentages for the half relationships versus the full relationships,

Nicole (28m 54s):
Right? So we have one half to the ninth plus one half to the ninth for those two relationship paths. And then for the last ancestral couple, Marcus, Daniel and Martha Daniel. So although they already appear in Joseph’s Pedigree as the grandparents of Robert Daniel, they also appear in another spot in Joseph’s Pedigree as the grandparents of EDA Hopper. So we need to include this path in our calculation to account for the extra DNA they passed through EDA to Joseph. So we would go up the Pedigree from Glen’s child to Robert Daniel the hypothesis and continued going up to Marcus, Daniel and Martha Daniel and then down five more steps to Joseph and this time we would go through Edna Hopper instead of through Robert Daniel like we did did in our first relationship path with Robert Daniel.

Nicole (29m 45s):
And so one half to the ninth power is one over five 12 and we would do that twice and add those together. So we are adding up for all these five relationship paths, you know the first one which was 0.03125 and then all the other ones are one half to the ninth. So if we can do four multiplied by 0.0 0 1 9 3 5 and add that to 0.3125, which makes a coefficient of relationship of 0.039 or 3.9%. So that’s a lot of numbers but just know you can look at the blog post to see all of the explanations for that,

Diana (30m 27s):
Right? And so we are usually used to using number of Cent Morgans to compare DNA matches to our test takers. So we do see these percentages on some of the DNA testing websites, but how do we translate that into Cent Morgans,

Nicole (30m 45s):
Right? That’s exactly what I wanted to do first as well. Like what does this mean in terms of Cent Morgans? So to convert a percentage or the coefficient relationship into Cent Morgans, we can multiply the coefficient by 7000 cent Morgans. So 0.039 times 7000 cent Morgans equals 273 cent Morgans. Oh that’s interesting. Coefficient of relationship formula predicts that Glen’s child should share about 273 with Joseph. If Robert Daniel is the father of Glen, the actual amount they share is 239, which is pretty close. So that’s just a difference of 34 cent of Morgans So. It could be that our hypothesis is correct.

Nicole (31m 26s):
In the past many have used 6800 cent Morgans as the total genome size to multiply by when converting percentages of shared DNA into Cent Morgans. However, Lea Larkin reviewed my article and suggested using 7000 cents instead of 6800 cent Morgans because that 6,800 was based on an old map by family tree dna. And she says that the genome size at each testing company varies but most are either slightly over or under 3500 cents. And when you double that for both sets of chromosomes, maternal and paternal, the total genome size would be 7,000. Oh that’s good to know. And those are nice round numbers, you know, 3,500 from each parent, 7,000 total.

Nicole (32m 9s):
I like that. All right, so this is all with that first hypothesis for the father of Glen Hopper and in an unknown parentage case we often need to have another hypothesis to test. So did you have another hypothesis and what would that be? Yes. So in order to get to proof for these kind of cases, we need to eliminate all the other hypotheses so that you’re only left with one conclusion that could be right. So we need to test some other ones to see if they would also work. So we looked, you know, at the family of Robert Daniel and he had a bunch of older brothers, so perhaps one of Robert Daniel’s older brothers, James George Luther or Jesse was the father of Glen.

Nicole (32m 50s):
In that case, we would need to adjust one part of our coefficient of relationship estimate and instead of having a half first cousin once removed relationship with Joseph through Robert Daniel Glen’s child would be a second cousin once removed through the parents of Robert, Daniel Marcus, Daniel Jr. And Jane Hopper, the coefficient of relationship calculation would now include two paths, one to Marcus Daniel Jr, and one to Jane Hopper, the parents of Robert Daniel. And so then we would have six paths instead of five, but they would be a little bit further back and more generations of separation. As a side note here, you might be wondering, oh no, another person with a surname hopper and that’s correct, we saw that as well.

Nicole (33m 38s):
Jane Hopper, you know, are they related again through this woman so far the research has found that she was not a daughter of Robert Anderson Hopper and Susan Pollard, but her parentage is unknown, we assume she is probably related further back, but research is ongoing on that. So there could be yet another instance of Pedigree Collapse from that for both the test speaker and the match. That’s another confounding factor in our hypothesis. Back to this second hypothesis here with this hypothesis, the calculation for the coefficient of relationship came out to 2.34% and to express this incentive organs we multiplied by 7,000, which is 164 cent Morgans.

Nicole (34m 23s):
So that’s a little bit lower than the amount that Joseph and Glen share, which is 239. And so that’s 75 cent Morgans less. So both hypotheses actually seem possible, right? They’re not that far away from how much they share. And with the confounding factor of Jane Hopper and possibly more Pedigree Collapse distantly of a tree, it’s possible that that could be contributing extra DNA as well. Unfortunately, after doing these calculations, we cannot make a conclusion we need to do more work. So we, we don’t know which hypothesis is accurate because they’re both kind of falling close enough where you know, because of random recombination some people just inherit a little more or a little less than the average statistical amount that you would expect them to share based on having the DNA in each generation.

Nicole (35m 21s):
I inherited 28% from one of my grandparents and 22 from the other. So it’s not an actual like forced like one half every time it’s only one half for your parents. But then from grandparents it could be like 20 and 30

Diana (35m 36s):
And it gets more pronounce that difference as you go further back on the family tree. You know, we see second or third cousins that are brothers and sisters or first cousins and they’re Matching much differently than you would expect So it, it can get tricky with that random recombination.

Nicole (35m 55s):
It can. And because we only talked about one data point in this case study, it’s hard to see if the amount of shared DNA we observe between Glen’s child and Joseph is an outlier. If we had several data points and they all pointed to, you know, clustering around this being closer with Robert as Glen’s father, then we would have a stronger case. But we would also need to eliminate Robert’s brothers as potential fathers. And one way to do this is by testing descendants of his brothers and his other siblings,

Diana (36m 27s):
Right? We’re always looking for more people that can add further evidence to our DNA conclusions. So what were your final conclusions?

Nicole (36m 35s):
The intermediate conclusion is that both hypothesis one and hypothesis two are possible and the future research that needs to be done is to identify additional test takers and matches to confirm or reject the hypothesis that Robert Daniel was the father. Of course we have some documentary evidence pointing to him on the social security application So, it seems that that’s slightly more likely than the others, but because there was already a conflict with the family information saying Dan Daniel, we wonder if there was some kind of confusion or not wanting to tell the truth about it. So we can’t take that as truth, right? It would be confirmation biased to say, okay, well it looks like this is what it says in documentary evidence and so we’re just gonna go with that because that hypothesis seems to work.

Nicole (37m 23s):
First we need to eliminate the other brothers. One way to prioritize additional test takers is to focus on any test takers whose ancestors did not intermarry with the same population. And Paul Woodbury calls these genetic pioneers and this is super important for endo me and it can also also be useful for Pedigree Collapse. And so we would hopefully try to find a, a test taker who descends from one of the brothers of Robert Daniel who doesn’t have any extra hopper ancestors in their tree beyond what’s already intermarried between Robert Daniel married at a hopper. It’s

Diana (37m 59s):
Always so exciting when you can find someone that moved away from the mess and then you can test one of their descendants and see if you can get a little bit cleaner tree without all of the Pedigree Collapse or multiple relationships. So that’s a good concept too. I just think it’s really important to remember that we have to have more than one test taker generally, like you said, data points. We can’t just rely on our own DNA or the DNA of our parent to prove something when we have these really difficult cases and especially if we’ve got something that’s so close, like these two different hypotheses. Well now that we’ve talked through some of this information about coefficient of relationship, I’m sure everyone listening would like to know where they can go to learn more.

Diana (38m 46s):
Because if, if you listeners are like me, you know it’s gonna take a few times to get this through your head and you’ll need to look at some examples and really have some good tools for using this in your own research. So Nicole, where do we learn more?

Nicole (38m 59s):
Right? So in order to figure out how to do this, I read everything I could about Pedigree Collapse. So I have a big list of resources at the end of the article that I consulted and one of them was Diane Suthers blog, your DNA Guide, and she has some really great explanations. One of the writers on their team, Jane Ekins, wrote the blog post about coefficient of relationship and Pedigree Collapse. So be sure to check that one out. I also read the chapter in Advanced Genetic Genealogy by Kimberly Powell and that one is really well done and I reached out to her with some questions and she clarified some things for me. Her example is, is great because it includes both the test taker and the DNA match.

Nicole (39m 40s):
Having Pedigree Collapse on my example, only the match had Pedigree Collapse. And so her example has Pedigree Collapse as well as multiple relationships. And you know, I did five and six distinct relationship paths with this case study. And her example had 10 distinct relationship paths and they were a little bit further back So. It resulted in a coefficient of relationship of about 1.76%. And so what she used in hers was one diagram that showed all of the relationships between the match and the test taker. And she used like the genetics Pedigree diagram with the males as squares and the females as circles.

Nicole (40m 21s):
And then she just labeled each common ancestor with a letter A through J to succinctly identify relationship paths between them. And so she lists out all 10 relationship paths saying like through a E and H and then through a J and H and stuff like that So. It was really helpful to to trace those paths in her diagram and then see the list of them and then see how she calculated each one. And hers were like one half raised to the ninth power, one half raised to the 10th power, so they were a little more distant. Go check out that chapter in the book, advanced Genetic Genealogy edited by Debbie Parker. Wayne and Kimberly also shows two methods of calculating the expected amount of shared DNA with Pedigree Collapse, the coefficient of relationship, of course like I’ve been saying, but also using the expected percentages of shared DNA for relationships based on the autosomal DNA statistics page at the ISO wiki.

Nicole (41m 15s):
And for this method, Kimberly used a matrix showing the relationships between the test taker and the match and the expected percentages of dna. Then she added up all these percentages and the answer was very similar to the coefficient of relationship calculation. So if you wanna do it that way, you might prefer that both are good.

Diana (41m 35s):
Yeah, I’m looking at that chapter right now and I had read this book when it first came out, but that’s been a while and I am loving all of the visuals that Kimberly’s got in this chapter. So if you’re really interested in learning more about DNA and some of these more complicated scenarios, you’ll probably want to get the book Advanced Genetic Genealogy Techniques in case studies, which has got several chapters by all sorts of different genetic genealogies. And it is edited by Debbie Parker Wayne. So good tool to have on hand when you run up against something like this

Nicole (42m 10s):
And you can even get the book from the library and that’s what one of our colleagues has done when she needs to consult it. But I had to ask Kimberly because when I was looking at the diagram image 6.7, I felt like there was one connecting line missing and I just couldn’t figure out how it was gonna work out without that line. And so I asked her and she said, yes, that line got deleted in the final draft somehow. And so in my blog post and the footnote for that, you can see she sent me a couple corrections for that and one of the relationship pass was raised to the wrong power. So anyways, it’s sad because Debbie Parker Wayne passed away and so she’s not gonna be able to do a new addition of the book eventually.

Nicole (42m 51s):
So if you have questions, you can always reach out to the chapter authors.

Diana (42m 55s):
That’s a disappointing when you’ve worked so hard on a chapter and have all of your diagrams perfect. And then in the printing or the editing or you know how that happens that something gets messed up. Oh darn

Nicole (43m 6s):
It. Yeah. And it’s, it’s super, it’s a big loss for the genetic Genealogy community. Yeah, with the passing of Debbie Parker Wayne a couple years ago

Diana (43m 13s):
Because she was such a pioneer in genetic Genealogy and just did so much to explain and teach.

Nicole (43m 19s):
Yeah, I’m really grateful for the book that she put together. I mean, I’ve consulted it many times and it’s just great to have experts sharing more advanced information.

Diana (43m 28s):
Well, my very first book that I studied was edited by Debbie, or written by Debbie and Blaine Beninger, it’s Genetic Genealogy and Practice. And I took that book and worked on it every day and studied it so I could learn the basics of dna. And it was extremely helpful as a good foundation. So even though it’s, you know, now it’s getting a little bit old, but the basic DNA principles of certainly not changed, of inheritance and how you work with it. So this book was written or it was copyrighted in 2016, which isn’t that old I guess. But you know, the world of DNA

Nicole (44m 6s):
Changes. It’s so crazy how much it changes when we edit our research like a Pro with DNA slides every year we have to make all these changes.

Diana (44m 15s):
Yes. And my, my lesson is on ethnicity and every single company has done an ethnicity update by the time the next year comes around. So that’s fun. But I, I love it. I think it’s great that we’re constantly getting updates. It’s really neat. Well let’s wrap up this podcast with your main takeaways after you’ve done all this study to write this and teach us all about it, what should we remember?

Nicole (44m 40s):
So the takeaways for this case study are checking for runs of Homozygosity with the JED Match tool are your parents related, which I didn’t use with the Glen Hopper case study, but it’s just such a good easy way if your test taker or match is at jma to quickly find out if there’s Pedigree Collapse and it’s free. Another takeaway is that you can visualize a JCOM file to see Pedigree Collapse at learn forever learn.com/ancestors using the exploring family tree visualization tool. Another takeaway is to be careful when you review pedigrees of a test taker and a match looking for Pedigree Collapse or multiple relationships and extending that Pedigree back as far as you can on all lines is really important.

Nicole (45m 30s):
And if Pedigree Collapse occurs in one of your DNA matches trees and the RCA couple is in their tree twice, that’s going to impact it. If it’s on the RCA couple that’s in there twice, if they have Pedigree Collapse with a different couple that’s not the Mrca couple, then that may not be relevant to your match with them. So just check for those inflated amounts of shared dna. Another takeaway, calculate the coefficient of relationship to estimate expected amounts of shared DNA for each relationship path to a common ancestor. And then if there’s Pedigree Collapse, then that ancestral couple could appear as a separate path. And then what do you do about all this while you incorporate more test takers and focus on genetic pioneers?

Nicole (46m 15s):
Consider Y DNA and mitochondrial DNA tests. Those direct line tests are often very helpful in untangling Pedigree Collapse in Endo. And we had used that Y DNA test to help us figure out the surname for Glen Hopper’s father, and that ended up being helpful. And then lastly, be sure to, to reach out to those who have worked with Pedigree Collapse before for advice. And I did that with this article and I was really grateful to receive feedback from Leah Larkin and Kimberly Powell and Paul Woodbury and a couple of our colleagues that I work with at Family Lock at Genealogies. So thank you to Yvonne and to all of the people who helped me make sure I had this right.

Diana (46m 56s):
Yeah, you know, it’s one thing to read about it, it’s another thing to actually work with it and it’s even harder to write about it and to make sure that you have it really understood, but it’s really a good way to get it really internalized because now you’ve got this down right

Nicole (47m 15s):
Before I understood it in theory, but now I understand it more in practice because applying it, you have to really dive in and make sure you get the concept.

Diana (47m 24s):
You really do. Totally. You do. And I think that’s why we enjoy doing our client works so much because we gotta try so many different projects and why we enjoy our study groups because we get to see so many different examples and we wanted to do this entire series on inmy multiple relationships and Pedigree Collapse because we see this over and over in our study groups with people doing the leads method and then thinking, oh, I’ve got a dog atmy or gut Pedigree Collapse. You know? So being able to really understand what each one of those scenarios is and how the DNA works is just so helpful. And I’m excited that we are doing the series and hopefully it’s helping everyone listen to it, at least to just know that it’s out there and when you need to, you can refer back to these podcasts or blog posts to learn more.

Nicole (48m 15s):
Right. And you know, we didn’t talk at all about the effect of Pedigree Collapse on clustering, but we do have a blog post in the works, so that’ll be coming out soon to, to kind of look at it from a clustering standpoint and genetic networks and how that Pedigree Collapse can make that a little more fuzzy.

Diana (48m 34s):
Right, right. Well I think it’s just encouraging that even though you’ve got some of these sticky situations in your family tree or those of your DNA matches, there are ways to work with them. And we don’t just have to throw our hands up in the air and say, oh, it’s impossible. You know, there’s some stuff we can do. And I think that’s always really good to know and people are figuring out better and better ways to work with it too, which is exciting.

Nicole (48m 59s):
It is exciting. And you know, even like right after I published this, I got an email from somebody who is working on a tool to help calculate the coefficient of relationship more efficiently. So that’s exciting,

Diana (49m 11s):
Right? Every time we talk about these really tricky things to calculate or figure out, my hope is always that someone will do a tool and you know that, that I can just plug my data into and it will tell me something. So,

Nicole (49m 24s):
Well, hey, that actually happened recently with the coverage estimator. I

Diana (49m 29s):
Know. See, I just had to wait for the tool and then I didn’t have to learn how to do it myself.

Nicole (49m 35s):
That was a tricky one. Yeah, we had talked on the podcast about calculating coverage and then, and I think kind of at the same time that we were talking about that Paul Woodbury and Leah Larkin and Johnny Pearl were working on making a tool. And so now you can find that coverage estimator tool at DNA painter. It’s pretty

Diana (49m 54s):
Great. It is pretty great. Yep. We love it. Well, thanks everyone for listening and thanks Nicole for doing all this work. I know it was a lot of work for you to, to get this all down in a good example that we could understand. So I encourage everyone to go check out the blog post, listen to this podcast again, let these concepts kind of soak in. And then when you’re working on your DNA research and you come across some of these situations, you’ll have at least in the back of your mind an idea of what to do. So have a great week everyone, and we’ll talk to you next time.

Nicole (50m 28s):
All right, bye bye. Bye. Thank you for listening. We hope that something you heard today will help you make progress in your research. If you want to learn more, purchase our books, Research Like a Pro and Research Like a Pro with DNA on Amazon.com and other booksellers. You can also register for our online courses or study groups of the same names. Learn more at FamilyLocket.com/services. To share your progress and ask questions, join our private Facebook group by sending us your book receipt or joining our courses to get updates in your email inbox each Monday, subscribe to our newsletter at FamilyLocket.com/newsletter. Please subscribe, rate and review our podcast. We read each review and are so thankful for them. We hope you’ll start now to Research Like a Pro.