Concepts: Chromosome Browser – What Is It, How Do I Use It, and Why Do I Care?

The goal of genetic genealogy is to utilize DNA matches to verify known ancestors and identify unknown ancestors.

A chromosome browser is a tool that allows testers to visualize and compare their DNA on each chromosome with that of their genetic matches. How to utilize and interpret that information becomes a little more tricky.

I’ve had requests for one article with all the information in one place about chromosome browsers:

  • What they are
  • How and when to use them
  • Why you’d want to

I’ve included a feature comparison chart and educational resource list at the end.

I would suggest just reading through this article the first time, then following along with your own DNA results after you understand the basic landscape. Using your own results is the best way to learn anything.

What Does a Chromosome Browser Look Like?

Here’s an example of a match to my DNA at FamilyTreeDNA viewed on their chromosome browser.

browser example.png

On my first 16 chromosomes, shown above, my 1C1R (first cousin once removed,) Cheryl, matches me where the chromosomes are painted blue. My chromosome is represented by the grey background, and her matching portion by the blue overlay.

Cheryl matches me on some portion of all chromosomes except 2, 6, and 13, where we don’t match at all.

You can select any one person, like Cheryl, from your match list to view on a chromosome browser to see where they match you on your chromosomes, or you can choose multiple matches, as shown below.

browser multiple example.png

I selected my 7 closest matches that are not my immediate family, meaning not my parents or children. I’m the background grey chromosome, and each person’s match is painted on top of “my chromosome” in the location where they match me. You see 7 images of my grey chromosome 1, for example, because each of the 7 people being compared to me are shown stacked below one another.

Everyplace that Cheryl matches me is shown on the top image of each chromosome, and our matching segment is shown in blue. The same for the second red copy of the chromosome, representing Don’s match to me. Each person I’ve selected to match against is shown by their own respective color.

You’ll note that in some cases, two people match me in the same location. Those are the essential hints we are looking for. We’ll be discussing how to unravel, interpret, and use matches in the rest of this article.

browser MyHeritage example.png

The chromosome browser at MyHeritage looks quite similar. However, I have a different “top 7” matches because each vendor has people who test on their platform who don’t test or transfer elsewhere.

Each vendor that supports chromosome browsers (FamilyTreeDNA, MyHeritage, 23andMe, and GedMatch) provides their own implementation, of course, but the fundamentals of chromosome browsers, how they work and what they are telling us is universal.

Why Do I Need a Chromosome Browser?

“But,” you might say, “I don’t need to compare my DNA with my matches because the vendors already tell me that I match someone, which confirms that we are related and share a common ancestor.”

Well, not exactly. It’s not quite that straightforward.

Let’s take a look at:

  • How and why people match
  • What matches do and don’t tell you
  • Both with and without a chromosome browser

In part, whether you utilize a chromosome browser or not depends on which of the following you seek:

  • A broad-brush general answer; yes or no, I match someone, but either I don’t know how are related, or have to assume why. There’s that assume word again.
  • To actually confirm and prove your ancestry, getting every ounce of value out of your DNA test.

Not everyone’s goals are the same. Fortunately, we have an entire toolbox with a wide range of tools. Different tools are better suited for different tasks.

People seeking unknown parents should read the article, Identifying Unknown Parents and Individuals Using DNA Matching because the methodology for identifying unknown parents is somewhat different than working with genealogy. This article focuses on genealogy, although the foundation genetic principles are the same.

If you’re just opening your DNA results for the first time, the article, First Steps When Your DNA Results are Ready – Sticking Your Toe in the Genealogy Water would be a great place to start.

Before we discuss chromosome browsers further, we need to talk about DNA inheritance.

Your Parents

Every person has 2 copies of each of their 22 chromosomes – one copy contributed by their mother and one copy contributed by their father. A child receives exactly half of the autosomal DNA of each parent. The DNA of each parent combines somewhat randomly so that you receive one chromosome’s worth of DNA from each of your parents, which is half of each parent’s total.

On each chromosome, you receive some portion of the DNA that each parent received from their ancestors, but not exactly half of the DNA from each individual ancestor. In other words, it’s not sliced precisely in half, but served up in chunks called segments.

Sometimes you receive an entire segment of an ancestor’s DNA, sometimes none, and sometimes a portion that isn’t equal to half of your parent’s segment.

browser inheritance.png

This means that you don’t receive exactly half of the DNA of each of your grandparents, which would be 25% each. You might receive more like 22% from one maternal grandparent and 28% from the other maternal grandparent for a total of 50% of the DNA you inherit from your parents. The other 50% of your DNA comes from the other parent, of course. I wrote about that here.

There’s one tiny confounding detail. The DNA of your Mom and Dad is scrambled in you, meaning that the lab can’t discern scientifically which side is which and can’t tell which pieces of DNA came from Mom and which from Dad. Think of a genetic blender.

Our job, using genetic genealogy, is to figure out which side of our family people who match us descend from – which leads us to our common ancestor(s).

Parallel Roads

For the purposes of this discussion, you’ll need to understand that the two copies you receive of each chromosome, one from each parent, have the exact same “addresses.” Think of these as parallel streets or roads with identical addresses on each road.

browser street.png

In the example above, you can see Dad’s blue chromosome and Mom’s red chromosome as compared to me. Of course, children and parents match on the full length of each chromosome.

I’ve divided this chromosome into 6 blocks, for purposes of illustration, plus the centromere where we generally find no addresses used for genetic genealogy.

In the 500 block, we see that the address of 510 Main (red bar) could occur on either Dad’s chromosome, or Mom’s. With only an address and nothing more, you have no way to know whether your match with someone at 510 Main is on Mom’s or Dad’s side, because both streets have exactly the same addresses.

Therefore, if two people match you, at the same address on that chromosome, like 510 Main Street, they could be:

  • Both maternal matches, meaning both descended from your mother’s ancestors, and those two people will also match each other
  • Both paternal matches, meaning both descended from your father’s ancestors, and those two people will also match each other
  • One maternal and one paternal match, and those two people will not match each other

Well then, how do we know which side of the family a match descends from, and how do we know if we share a common ancestor?

Good question!

Identical by Descent

If you and another person match on a reasonably sized DNA segment, generally about 7 cM or above, your match is probably “identical by descent,” meaning not “identical by chance.” In this case, then yes, a match does confirm that you share a common ancestor.

Identical by descent (IBD) means you inherited the piece of DNA from a common ancestor, inherited through the relevant parent.

Identical by chance (IBC) means that your mom’s and dad’s DNA just happens to have been inherited by you randomly in a way that creates a sequence of DNA that matches that other person. I wrote about both IBD and IBC here.

MMB stats by cM 2

This chart, courtesy of statistician Philip Gammon, from the article Introducing the Match-Maker-Breaker Tool for Parental Phasing shows the percentage of time we expect matches of specific segment sizes to be valid, or identical by descent.

Identical by Chance

How does this work?

How is a match NOT identical by descent, meaning that it is identical by chance and therefore not a “real” or valid match, a situation also known as a false positive?

browser inheritance grid.png

The answer involves how DNA is inherited.

You receive a chromosome with a piece of DNA at every address from both parents. Of course, this means you have two pieces of DNA at each address. Therefore people will match you on either piece of DNA. People from your Dad’s side will match you on the pieces you inherited from him, and people from your Mom’s side will match you on the pieces you inherited from her.

However, both of those matches have the same address on their parallel streets as shown in the illustration, above. Your matches from your mom’s side will have all As, and those from your dad’s side will have all Ts.

The problem is that you have no way to know which pieces you inherited from Mom and from Dad – at least not without additional information.

You can see that for 10 contiguous locations (addresses), which create an example “segment” of your DNA, you inherited all As from your Mom and all Ts from your Dad. In order to match you, someone would either need to have an A or a T in one of their two inherited locations, because you have an A and a T, both. If the other person has a C or a G, there’s no match.

Your match inherited a specific sequence from their mother and father, just like you did. As you can see, even though they do match you because they have either an A or a T in all 10 locations – the As and Ts did not all descend from either their mother or father. Their random inheritance of Ts and As just happens to match you.

If your match’s parents have tested, you won’t match either of their parents nor will they match either of your parents, which tells you immediately that this match is by chance (IBC) and not by descent (IBD), meaning this segment did not come from a common ancestor. It’s identical by chance and, therefore, a false positive.

If We Match Someone Else In Common, Doesn’t That Prove Identical by Descent?

Nope, but I sure wish it did!

The vendors show you who else you and your match both match in common, which provides a SUGGESTION as to your common ancestor – assuming you know which common ancestor any of these people share with you.

browser icw.png

However, shared matches are absolutely NOT a guarantee that you, your match, and your common matches all share the same ancestor, unless you’re close family. Your shared match could match you or your match through different ancestors – or could be identical by chance.

How can we be more confident of what matching is actually telling us?

How can we sort this out?

Uncertainties and Remedies

Here’s are 9 things you DON’T know, based on matching alone, along with tips and techniques to learn more.

  1. If your match to Person A is below about 20cM, you’ll need to verify that it’s a legitimate IBD match (not IBC). You can achieve this by determining if Person A also matches one of your parents and if you match one of Person A’s parents, if parents have tested.

Not enough parents have tested? An alternative method is by determining if you and Person A both match known descendants of the candidate ancestors ON THE SAME SEGMENT. This is where the chromosome browser enters the picture.

In other words, at least three people who are confirmed to descend from your presumptive common ancestor, preferably through at least two different children, must match on a significant portion of the same segment.

Why is that? Because every segment has its own unique genealogical history. Each segment can and often does lead to different ancestors as you move further back in time.

In this example, I’m viewing Buster, David, and E., three cousins descended from the same ancestral couple, compared to me on my chromosome browser. I’m the background grey, and they show in color. You can see that all three of them match me on at least some significant portion of the same segment of chromosome 15.

browser 3 cousins.png

If those people also match each other, that’s called triangulation. Triangulation confirms descent from a common ancestral source.

In this case, I already know that these people are related on my paternal side. The fact that they all match my father’s DNA and are therefore all automatically assigned to my paternal matching tab at Family Tree DNA confirms my paper-trail genealogy.

I wrote detailed steps for triangulation at Family Tree DNA, here. In a nutshell, matching on the same segment to people who are bucketed to the same parent is an automated method of triangulation.

Of course, not everyone has the luxury of having their parents tested, so testing other family members, finding common segments, and assigning people to their proper location in your tree facilitates confirmation of your genealogy (and automating triangulation.)

The ONLY way you can determine if people match you on the same segment, and match each other, is having segment information available to you and utilizing a chromosome browser.

browser MyHeritage triangulation.png

In the example above, the MyHeritage triangulation tool brackets matches that match you (the background grey) and who are all triangulated, meaning they all also match each other. In this case, the portion where all three people match me AND each other is bracketed. I wrote about triangulation at MyHeritage here.

  1. If you match several people who descend from the same ancestor, John Doe, for example, on paper, you CANNOT presume that your match to all of those people is due to a segment of DNA descended from John Doe or his wife. You may not match any of those people BECAUSE OF or through segments inherited from John Doe or his wife. You need segment information and a chromosome browser to view the location of those matches.

Assuming these are legitimate IBD matches, you may share another common line, known or unknown, with some or all of those matches.

It’s easy to assume that because you match and share matches in common with other people who believe they are descended from that same ancestor:

  • That you’re all matching because of that ancestor.
  • Even on the same segments.

Neither of those presumptions can be made without additional information.

Trust me, you’ll get yourself in a heap o’ trouble if you assume. Been there, done that. T-shirt was ugly.

Let’s look at how this works.

browser venn.png

Here’s a Venn diagram showing me, in the middle, surrounded by three of my matches:

  • Match 1 – Periwinkle, descends from Lazarus Estes and Elizabeth Vannoy
  • Match 2 – Teal, descends from Joseph Bolton and Margaret Claxton
  • Match 3 – Mustard, descends from John Y. Estes and Rutha Dodson

Utilizing a chromosome browser, autocluster software, and other tools, we can determine if those matches also match each other on a common segment, which means they triangulate and confirm common ancestral descent.

Of course, those people could match each other due to a different ancestor, not necessarily the one I share with them nor the ancestors I think we match through.

If they/we do all match because they descend from a common ancestor, they can still match each other on different segments that don’t match me.

I’m in the center. All three people match me, and they also match each other, shown in the overlap intersections.

Note that the intersection between the periwinkle (Match 1) and teal (Match 2) people, who match each other, is due to the wives of the children of two of my ancestors. In other words, their match to each other has absolutely nothing to do with their match to me. This was an “aha’ moment for me when I first realized this was a possibility and happens far more than I ever suspected.

The intersection of the periwinkle (Match 1) and mustard (Match 3) matches is due to the Dodson line, but on a different segment than they both share with me. If they had matched each other and me on the same segment, we would be all triangulated, but we aren’t.

The source of the teal (Match 2) to mustard (Match 3) is unknown, but then again, Match 3’s tree is relatively incomplete.

Let’s take a look at autocluster software which assists greatly with automating the process of determining who matches each other, in addition to who matches you.

  1. Clustering technology, meaning the Leeds method as automated by Genetic Affairs and DNAGedcom help, but don’t, by themselves, resolve the quandary of HOW people match you and each other.

People in a colored cluster all match you and each other – but not necessarily on the same segment, AND, they can match each other because they are related through different ancestors not related to your ancestor. The benefit of autocluster software is that this process is automated. However, not all of your matches will qualify to be placed in clusters.

browser autocluster.png

My mustard cluster above includes the three people shown in the chromosome browser examples – and 12 more matches that can be now be researched because we know that they are all part of a group of people who all match me, and several of whom match each other too.

My matches may not match each other for a variety of reasons, including:

  • They are too far removed in time/generations and didn’t inherit any common ancestral DNA.
  • This cluster is comprised of some people matching me on different (perhaps intermarried) lines.
  • Some may be IBC matches.

Darker grey boxes indicate that those people should be in both clusters, meaning the red and mustard clusters, because they match people in two clusters. That’s another hint. Because of the grid nature of clusters, one person cannot be associated with more than 2 clusters, maximum. Therefore, people like first cousins who are closely related to the tester and could potentially be in many clusters are not as useful in clusters as they are when utilizing other tools.

  1. Clusters and chromosome browsers are much less complex than pedigree charts, especially when dealing with many people. I charted out the relationships of the three example matches from the Venn diagram. You can see that this gets messy quickly, and it’s much more challenging to visualize and understand than either the chromosome browser or autoclusters.

Having said that, the ultimate GOAL is to identify how each person is related to you and place them in their proper place in your tree. This, cumulatively with your matches, is what identifies and confirms ancestors – the overarching purpose of genealogy and genetic genealogy.

Let’s take a look at this particular colorized pedigree chart.

Browser pedigree.png

click to enlarge

The pedigree chart above shows the genetic relationship between me and the three matches shown in the Venn diagram.

Four descendants of 2 ancestral couples are shown, above; Joseph Bolton and Margaret Claxton, and John Y. Estes and Rutha Dodson. DNA tells me that all 3 people match me and also match each other.

The color of the square (above) is the color of DNA that represents the DNA segment that I received and match with these particular testers. This chart is NOT illustrating how much DNA is passed in each generation – we already know that every child inherits half of the DNA of each parent. This chart shows match/inheritance coloring for ONE MATCHING SEGMENT with each match, ONLY.

Let’s look at Joseph Bolton (blue) and Margaret Claxton (pink). I descend through their daughter, Ollie Bolton, who married William George Estes, my grandfather. The DNA segment that I share with blue Match 2 (bottom left) is a segment that I inherited from Joseph Bolton (blue). I also carry inherited DNA from Margaret Claxton too, but that’s not the segment that I share with Match 2, which is why the path from Joseph Bolton to me, in this case, is blue – and why Match 2 is blue. (Just so you are aware, I know this segment descends from Joseph Bolton, because I also match descendants of Joseph’s father on this segment – but that generation/mtach is not shown on this pedigree chart.)

If I were comparing to someone else who I match through Margaret Claxton, I would color the DNA from Margaret Claxton to me pink in that illustration. You don’t have to DO this with your pedigree chart, so don’t worry. I created this example to help you understand.

The colored dots shown on the squares indicate that various ancestors and living people do indeed carry DNA from specific ancestors, even though that’s not the segment that matches a particular person. In other words, the daughter, Ollie, of Joseph Bolton and Margaret Claxton carries 50% pink DNA, represented by the pink dot on blue Ollie Bolton, married to purple William George Estes.

Ollie Bolton and William George Estes had my father, who I’ve shown as half purple (Estes) and half blue (Bolton) because I share Bolton DNA with Match 2, and Estes DNA with Match 1. Obviously, everyone receives half of each parent’s DNA, but in this case, I’m showing the path DNA descended for a specific segment shared with a particular match.

I’ve represented myself with the 5 colors of DNA that I carry from these particular ancestors shown on the pedigree chart. I assuredly will match other people with DNA that we’ve both inherited from these ancestors. I may match these same matches shown with DNA that we both inherited from other ancestors – for example, I might match Match 2 on a different segment that we both inherited from Margaret Claxton. Match 2 is my second cousin, so it’s quite likely that we do indeed share multiple segments of DNA.

Looking at Match 3, who knows very little about their genealogy, I can tell, based on other matches, that we share Dodson DNA inherited through Rutha Dodson.

I need to check every person in my cluster, and that I share DNA with on these same segment addresses to see if they match on my paternal side and if they match each other.

  1. At Family Tree DNA, I will be able to garner more information about whether or not my matches match each other by using the Matrix tool as well as by utilizing Phased Family Matching.

At Family Tree DNA, I determined that these people all match in common with me and Match 1 by using the “In Common With” tool. You can read more about how to use “In Common With” matching, here.

browser paternal.png

Family Matching phases the matches, assigning or bucketed them maternally or paternally (blue and red icons above), indicating, when possible, if these matches occur on the same side of your family. I wrote about the concept of phasing, here, and Phased Family Matching here and here.

Please note that there is no longer a limit on how distantly related a match can be in order to be utilized in Phased Family Matching, so long as it’s over the phase-matching threshold and connected correctly in your tree.

browser family tree dna link tree.png

Bottom line, if you can figure out how you’re related to someone, just add them into your tree by creating a profile card and link their DNA match to them by simply dragging and dropping, as illustrated above.

Linking your matches allows Family Matching to maternally or paternally assign other matches that match both you and your tree-linked matches.

If your matches match you on the same segment on the same parental side, that’s segment triangulation, assuming the matches are IBD. Phased Family Matching does this automatically for you, where possible, based on who you have linked in your tree.

For matches that aren’t automatically bucketed, there’s another tool, the Matrix.

browser matrix.png

In situations where your matches aren’t “bucketed” either maternally or paternally, the Matrix tool allows you to select matches to determine whether your matches also match each other. It’s another way of clustering where you can select specific people to compare. Note that because they also match each other (blue square) does NOT mean it’s on the same segment(s) where they match you. Remember our Venn diagram.

browser matrix grid.png

  1. Just because you and your matches all match each other doesn’t mean that they are matching each other because of the same ancestor. In other words, your matches may match each other due to another or unknown ancestor. In our pedigree example, you can see that the three matches match each other in various ways.
browser pedigree match.png

click to enlarge

  • Match 1 and Match 2 match each other because they are related through the green Jones family, who is not related to me.
  • Match 2 and Match 3 don’t know why they match. They both match me, but not on the same segment they share with each other.
  • Match 1 and Match 3 match through the mustard Dodson line, but not on the same segment that matches me. If we all did match on the same segment, we would be triangulated, but we wouldn’t know why Match 3 was in this triangulation group.
  1. Looking at a downloaded segment file of your matches, available at all testing vendors who support segment information and a chromosome browser, you can’t determine without additional information whether your matches also match each other.

browser chr 15.png

Here’s a group of people, above, that we’ve been working with on chromosome 15.

My entire match-list shows many more matches on that segment of chromosome 15. Below are just a few.

browser chr 15 all

Looking at seven of these people in the chromosome browser, we can see visually that they all overlap on part of a segment on chromosome 15. It’s a lot easier to see the amount of overlap using a browser as opposed to the list. But you can only view 7 at a time in the browser, so the combination of both tools is quite useful. The downloaded spreadsheet shows you who to select to view for any particular segment.

browser chr 15 compare.png

The critical thing to remember is that some matches will be from tyour mother’s side and some from your father’s side.

Without additional information and advanced tools, there’s no way to tell the difference – unless they are bucketed using Phased Family Matching at Family Tree DNA or bracketed with a triangulation bracket at MyHeritage.

At MyHeritage, this assumes you know the shared ancestor of at least one person in the triangulation group which effectively assigns the match to the maternal or paternal side.

Looking at known relatives on either side, and seeing who they also match, is how to determine whether these people match paternally or maternally. In this example below, the blue people are bucketed paternally through Phased Family Matching, the pink maternally, and the white rows aren’t bucketed and therefore require additional evaluation.

browser chr 15 maternal paternal.png

Additional research shows that Jonathan is a maternal match, but Robert and Adam are identical by chance because they don’t match either of my parents on this segment. They might be valid matches on other segments, but not this one.

browser chr 15 compare maternal paternal.png

  1. Utilizing relatives who have tested is a huge benefit, and why we suggest that everyone test their closest upstream relatives (meaning not children or grandchildren.) Testing all siblings is recommended if both parents aren’t available to test, because every child received different parts of their parents’ DNA, so they will match different relatives.

After deleting segments under 7 cM, I combine the segment match download files of multiple family members (who agree to allow me to aggregate their matches into one file for analysis) so that I can create a master match file for a particular family group. Sorting by match name, I can identify people that several of my cousins’ match.

browser 4 groups.png

This example is from a spreadsheet where I’ve combined the results of about 10 collaborating cousins to determine if we can break through a collective brick wall. Sorted by match name, this table shows the first 4 common matches that appear on multiple cousin’s match lists. Remember that how these people match may have nothing to do with our brick wall – or it might.

Note that while the 4 matches, AB, AG, ag, and A. Wayne, appear in different cousins’ match lists, only one shares a common segment of DNA: AB triangulates with Buster and Iona. This is precisely WHY you need segment information, and a chromosome browser, to visualize these matches, and to confirm that they do share a common DNA segment descended from a specific ancestor.

These same people will probably appear in autocluster groups together as well. It’s worth noting, as illustrated in the download example, that it’s much more typical for “in common with” matches to match on different segments than on the same segment. 

  1. Keep in mind that you will match both your mother and father on every single chromosome for the entire length of each chromosome.

browser parent matching.png

Here’s my kit matching with my father, in blue, and mother, in red on chromosomes 1 and 2.

Given that I match both of my parents on the full chromosome, inheriting one copy of my chromosome from each parent, it’s impossible to tell by adding any person at random to the chromosome browser whether they match me maternally or paternally. Furthermore, many people aren’t fortunate enough to have parents available for testing.

To overcome that obstacle, you can compare to known or close relatives. In fact, your close relatives are genetic genealogy gold and serve as your match anchor. A match that matches you and your close relatives can be assigned either maternally or paternally. I wrote about that here.

browser parent plus buster.png

You can see that my cousin Buster matches me on chromosome 15, as do both of my parents, of course. At this point, I can’t tell from this information alone whether Buster matches on my mother’s or father’s side.

I can tell you that indeed, Buster does match my father on this same segment, but what if I don’t have the benefit of my father’s DNA test?

Genealogy tells me that Buster matches me on my paternal side, through Lazarus Estes and Elizabeth Vannoy. Given that Buster is a relatively close family member, I already know how Buster and I are related and that our DNA matches. That knowledge will help me identify and place other relatives in my tree who match us both on the same segment of DNA.

To trigger Phased Family Matching, I placed Buster in the proper place in my tree at Family Tree DNA and linked his DNA. His Y DNA also matches the Estes males, so no adoptions or misattributed parental events have occurred in the direct Estes patrilineal line.

browser family tree dna tree.png

I can confirm this relationship by checking to see if Buster matches known relatives on my father’s side of the family, including my father using the “in common with” tool.

Buster matches my father as well as several other known family members on that side of the family on the same segments of DNA.

browser paternal bucket.png

Note that I have a total of 397 matches in common with Buster, 140 of which have been paternally bucketed, 4 of which are both (my children and grandchildren), and 7 of which are maternal.

Those maternal matches represent an issue. It’s possible that those people are either identical by chance or that we share both a maternal and paternal ancestor. All 7 are relatively low matches, with longest blocks from 9 to 14 cM.

Clearly, with a total of 397 shared matches with Buster, not everyone that I match in common with Buster is assigned to a bucket. In fact, 246 are not. I will need to take a look at this group of people and evaluate them individually, their genealogy, clusters, the matrix, and through the chromosome browser to confirm individual matching segments.

There is no single perfect tool.

Every Segment Tells a Unique History

I need to check each of the 14 segments that I match with Buster because each segment has its own inheritance path and may well track back to different ancestors.

browser buster segments.png

It’s also possible that we have unknown common ancestors due to either adoptions, NPEs, or incorrect genealogy, not in the direct Estes patrilineal line, but someplace in our trees.

browser buster paint.png

The best way to investigate the history and genesis of each segment is by painting matching segments at DNAPainter. My matching segments with Buster are shown painted at DNAPainter, above. I wrote about DNAPainter, here.

browser overlap.png

By expanding each segment to show overlapping segments with other matches that I’ve painted and viewing who we match, we can visually see which ancestors that segment descends from and through.

browser dnapainter walk back.png

These roughly 30 individuals all descend from either Lazarus Estes and Elizabeth Vannoy (grey), Elizabeth’s parents (dark blue), or her grandparents (burgundy) on chromosome 15.

As more people match me (and Buster) on this segment, on my father’s side, perhaps we’ll push this segment back further in time to more distant ancestors. Eventually, we may well be able to break through our end-of-line brick wall using these same segments by looking for common upstream ancestors in our matches’ trees.

Arsenal of Tools

This combined arsenal of tools is incredibly exciting, but they all depend on having segment information available and understanding how to use and interpret segment and chromosome browser match information.

One of mine and Buster’s common segments tracks back to end-of-line James Moore, born about 1720, probably in Virginia, and another to Charles Hickerson born about 1724. It’s rewarding and exciting to be able to confirm these DNA segments to specific ancestors. These discoveries may lead to breaking through those brick walls eventually as more people match who share common ancestors with each other that aren’t in my tree.

This is exactly why we need and utilize segment information in a chromosome browser.

We can infer common ancestors from matches, but we can’t confirm segment descent without specific segment information and a chromosome browser. The best we can do, otherwise, is to presume that a preponderance of evidence and numerous matches equates to confirmation. True or not, we can’t push further back in time without knowing who else matches us on those same segments, and the identity of their common ancestors.

The more evidence we can amass for each ancestor and ancestral couple, the better, including:

  • Matches
  • Shared “In Common With” Matches, available at all vendors.
  • Phased Family Matching at Family Tree DNA assigns matches to maternal or paternal sides based on shared, linked DNA from known relatives.
  • The Matrix, a Family Tree DNA tool to determine if matches also match each other. Tester can select who to compare.
  • ThruLines from Ancestry is based on a DNA match and shared ancestors in trees, but no specific segment information or chromosome browser. I wrote about ThruLines here and here.
  • Theories of Family Relativity, aka TOFR, at MyHeritage, based on shared DNA matches, shared ancestors in trees and trees constructed between matches from various genealogical records and sources. MyHeritage includes a chromosome browser and triangulation tool. I wrote about TOFR here and here.
  • Triangulation available through Phased Family Matching at Family Tree DNA and the integrated triangulation tool at MyHeritage. Triangulation between only 3 people at a time is available at 23andMe, although 23andMe does not support trees. See triangulation article links in the Resource Articles section below.
  • AutoClusters at MyHeritage (cluster functionality included), at Genetic Affairs (autoclusters plus tree reconstruction) and at DNAGedcom (including triangulation).
  • Genealogical information. Please upload your trees to every vendor site.
  • Y DNA and mitochondrial DNA confirmation, when available, through Family Tree DNA. I wrote about the 4 Kinds of DNA for Genetic Genealogy, here and the importance of Y DNA confirmation here, and how not having that information can trip you up.
  • Compiled segment information at DNAPainter allows you to combine segment information from various vendors, paint your maternal and paternal chromosomes, and visually walk segments back in time. Article with DNAPainter instructions is found here.

Autosomal Tool Summary Table

In order to help you determine which tool you need to use, and when, I’ve compiled a summary table of the types of tools and when they are most advantageous. Of course, you’ll need to read and understand about each tool in the sections above. This table serves as a reminder checklist to be sure you’ve actually utilized each relevant tool where and how it’s appropriate.

Family Tree DNA MyHeritage Ancestry 23andMe GedMatch
DNA Matches Yes Yes Yes Yes, but only highest 2000 minus whoever does not opt -in Yes, limited matches for free, more with subscription (Tier 1)
Download DNA Segment Match Spreadsheet Yes Yes No, must use DNAGedcom for any download, and no chromosome segment information Yes Tier 1 required, can only download 1000 through visualization options
Segment Spreadsheet Benefits View all matches and sort by segment, target all people who match on specific segments for chromosome browser View all matches and sort by segment, target all people who match on specific segments for chromosome browser No segment information but matches might transfer elsewhere where segment information is available View up to 2000 matches if matches have opted in. If you have initiated contact with a match, they will not drop off match list. Can download highest 1000 matches, target people who match on specific segments
Spreadsheet Challenges Includes small segments, I delete less than 7cM segments before using No X chromosome included No spreadsheet and no segment information Maximum of 2000 matches, minus those not opted in Download limited to 1000 with Tier 1, download not available without subscription
Chromosome Segment Information Yes Yes No, only total and longest segment, no segment address Yes Yes
Chromosome Browser Yes, requires $19 unlock if transfer Yes, requires $29 unlock or subscription if transfer No Yes Yes, some features require Tier 1 subscription
X Chromosome Included Yes No No Yes Yes, separate
Chromosome Browser Benefit Visual view of 7 or fewer matches Visual view of 7 or fewer matches, triangulation included if ALL people match on same portion of common segment No browser Visual view of 5 or fewer matches Unlimited view of matches, multiple options through comparison tools
Chromosome Browser Challenges Can’t tell whether maternal or paternal matches without additional info if don’t select bucketed matches Can’t tell whether maternal or paternal without additional info if don’t triangulate or you don’t know your common ancestor with at least one person in triangulation group No browser Can’t tell whether maternal or paternal without other information Can’t tell whether maternal or paternal without other information
Shared “In Common With” Matches Yes Yes Yes Yes, if everyone opts in Yes
Triangulation Yes, Phased Family Matching, plus chromosome browser Yes, included in chromosome browser if all people being compared match on that segment No, and no browser Yes, but only for 3 people if “Shared DNA” = Yes on Relatives in Common Yes, through multiple comparison tools
Ability to Know if Matches Match Each Other (also see autoclusters) Yes, through Matrix tool or if match on common bucketed segment through Family Matching Yes, through triangulation tool if all match on common segment No Yes, can compare any person to any other person on your match list Yes, through comparison tool selections
Autoclusters Can select up to 10 people for Matrix grid, also available for entire match list through Genetic Affairs and DNAGedcom which work well Genetic Affairs clustering included free, DNAGedcom has difficulty due to timeouts No, but Genetic Affairs and DNAGedcom work well No, but Genetic Affairs and DNAGedcom work well Yes, Genetic Affairs included in Tier 1 for selected kits, DNAGedcom is in beta
Trees Can upload or create tree. Linking you and relatives who match to tree triggers Phased Family Matching Can upload or create tree. Link yourself and kits you manage assists Theories of Family Relativity Can upload or create tree. Link your DNA to your tree to generate ThruLines. Recent new feature allows linking of DNA matches to tree. No tree support but can provide a link to a tree elsewhere Upload your tree so your matches can view
Matching and Automated Tree Construction of DNA Matches who Share Common Ancestors with You Genetic Affairs for matches with common ancestors with you Not available Genetic Affairs for matches with common ancestors with you No tree support Not available
Matching and Automated Tree Construction for DNA Matches with Common Ancestors with Each Other, But Not With You Genetic Affairs for matches with common ancestors with each other, but not with you Not available Genetic Affairs for matches with common ancestors with each other, but not with you No tree support Not available
DNAPainter Segment Compilation and Painting Yes, bucketed Family Match file can be uploaded which benefits tester immensely. Will be able to paint ethnicity segments soon. Yes No segment info available, encourage your matches to upload elsewhere Yes, and can paint ethnicity segments from 23andMe, Yes, but only for individually copied matches or highest 1000.
Y DNA and Mitochondrial Matching Yes, both, includes multiple tools, deep testing and detailed matching No No No, base haplogroup only, no matching No, haplogroup only if field manually completed by tester when uploading autosomal DNA file

Transfer Your DNA

Transferring your DNA results to each vendor who supports segment information and accepts transfers is not only important, it’s also a great way to extend your testing collar. Every vendor has strengths along with people who are found there and in no other database.

Ancestry does not provide segment information nor a chromosome browser, nor accept uploads, but you have several options to transfer your DNA file for free to other vendors who offer tools.

23andMe does provide a chromosome browser but does not accept uploads. You can download your DNA file and transfer free to other vendors.

I wrote detailed upload/download and transfer instructions for each vendor, here.

Two vendors and one third party support transfers into their systems. The transfers include matching. Basic tools are free, but all vendors charge a minimal fee for unlocking advanced tools, which is significantly less expensive than retesting:

Third-party tools that work with your DNA results include:

All vendors provide different tools and have unique strengths. Be sure that your DNA is working as hard as possible for you by fishing in every pond and utilizing third party tools to their highest potential.

Resource Articles

Explanations and step by step explanations of what you will see and what to do, when you open your DNA results for the first time.

Original article about chromosomes having 2 sides and how they affect genetic genealogy.

This article explains what triangulation is for autosomal DNA.

Why some matches may not be valid, and how to tell the difference.

This article explains the difference between a match group, meaning a group of people who match you, and triangulation, where that group also matches each other. The concepts are sound, but this article relies heavily on spreadsheets, before autocluster tools were available.

Parental phasing means assigning segment matches to either your paternal or maternal side.

Updated, introductory article about triangulation, providing the foundation for a series of articles about how to utilize triangulation at each vendor (FamilyTreeDNA, MyHeritage, 23andMe, GEDmatch, DNAPainter) that supports triangulation.

These articles step you through triangulation at each vendor.

DNAPainter facilitates painting maternally and paternally phased, bucketed matches from FamilyTreeDNA, a method of triangulation.

Compiled articles with instructions and ideas for using DNAPainter.

Autoclustering tool instructions.

How and why The Leeds Method works.

Step by step instructions for when and how to use FamilyTreeDNA’s chromosome browser.

Close family members are the key to verifying matches and identifying common ancestors.

This article details how much DNA specific relationships between people can expect to share.

Overview of transfer information and links to instruction articles for each vendor, below.

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Disclosure

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Transfers

Genealogy Products and Services

Genealogy Research

Fun DNA Stuff

  • Celebrate DNA – customized DNA themed t-shirts, bags, and other items

7 thoughts on “Concepts: Chromosome Browser – What Is It, How Do I Use It, and Why Do I Care?

  1. Thanks for sorting this all out so specifically & with excellent graphics for better understanding. I already know a good part of it but I read completely to keep everything in context, & where the parts I wasn’t as familiar with fit in. A lot to wrap my head around!!!

    Why will neither FTDNA nor 23&me allow us to actually print out the filled in chromosome browsers? Perhaps I’m missing something, but when I click on print (MacOS) I get a blank page so have to go in to reduce screen size as much as possible, then take 2-3 screen shots to get all the colored match data. Is this a Matches Privacy issue or perhaps proprietary information for the company?

  2. I am no longer able to get FTDNA to indicate my relationship to a DNA match when I enter the information in my tree. Maiden names will not show up in the tree. This is the part that does not work for me with the new software:
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    • Carolyn, If you haven’t already, please report this to support so they can document it as a bug.

      • The problems I have with my family tree began in December, maybe several months before that. I have sent detailed messages about what is wrong several times and each time been assured they would refer the problem to the tech department. The problem is their new software. If I could contact Bennett Greenspan, I would tell him what they had before was infinitely superior.

  3. Roberta,
    Awesome article as usual. I am so glad you defined certain aspects such as IBC and IBD and triangulation, I definitely have a better understanding of those terms now.
    I wish that Ancestry would do more on the aspect of what Family Tree DNA does with a matrix and a Chromosome Browser. Not that I don’t find the Thru-lines helpful but when other family trees lines keep certain people private then you have to go digging and only God knows where you will end up. Like coming to a fork in the road not knowing which direction to go. I do love Ancestry but it also is lacking and has issues too but I am sure that the rest of the testing sites have their own issues too.
    Well you definitely helped explain more with this article and I always learn more every time when I read these types of articles. Thank you and you are a God send for all this wealth of information…again thanks.

    Regards,

    Cindy Carrasco

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