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An Overview of the One-to-Many Tools on GEDmatch Genesis

GEDmatch One-to-Many Tool

Many people take a genealogy DNA test to find cousins. GEDmatch has released its Genesis upgrade with a host of great tools you’ll want to use to find your cousins. One tool to try is the One-to-Many tool on GEDmatch Genesis.

When you log into Genesis, the One-to-Many tool is going to be down under DNA applications. You still have access to this tool for those of you who do not have a tier-one membership.

Start with the One-to-Many comparison result.

Enter a kit number.

  1. This can be one of the kit numbers that you manage.

  2. It can also be any other kit number that is publicly available.

UNDERSTAND THE ONE-to-MANY Comparison Columns

You’ll see a table that is your One-to-Many comparison.

Each of the columns displays different information.

Kit Numbers -- this column displays the kits that you match. Each one is hyperlinked. If you click on the link, a new One-to-Many table will open up for that kit number. You can actually jump from kit to kit.

One-to-One: The second column is actually a tool to make a One-to-One comparison between your kit and the kit in that row. I’ll explain One-to-One comparisons in a later video.

Name & Email: This is the information to identify that kit number. Many people in the name field actually use an alias. The email is the email contact that you will use to contact the person that manages that kit. One thing to remember is, as you can see here, a lot of people manage multiple kits. In fact, if you come up with dna@lee, that means you match one of my kits. But I have a ton of kits. The kids belong to both my lines and my wife’s side of the family. In short, don’t assume that the person that you’re matching with is the person that’s going to be answering the email. Make sure whenever you email somebody, you include that kit number and that alias.

Largest segment -- Displays the largest segment in centimorgans that you share with that person. You’ll often see a fairly big number at the top of the list if you have very close relatives. As you go down further in the list, you may find that the number of centimorgans that you match is the same as the total centimorgans. That means that you match on just one segment.

Total centimorgans -this column is telling you how much total shared cMs you have. This is usually a good identifier of how closely you’re related. In some cases, you can actually identify what that relationship is just based on the number of centimorgans that this column shows.

Generations -this is an estimate of how many generations removed you and the specific kit is. In other words, how far removed is this person is to this next person. A small relationship is going to be either a twin or your parents. It will go to grandparents, then aunts and uncles, cousins, first cousins when you get further away. Etc. It’s really not a good predictor of how closely you’re related other than the fact that hey, you’re at least four generations removed. However, you could be distantly related.

Amount of DNA Overlap-- This column is interesting because this is part of why Genesis was created. You can see “N/a” with a lot of these entries. These kits were uploaded into the old GEDmatch system. They were initially analyzed using the GEDmatch algorithms. As you go down your list, you’re going to come across some that have a number and a color that highlights the overlap. This is the number of SNPs that are being used to compare these two kits. The more SNPs you see, the better. In one example, the color is red. This means it’s not necessarily an excellent comparison. Further down, you may see one that has 133,000 SNPs being compared. It doesn’t have a color at all, which indicates that this is a much better comparison.

Date-compared: this is the last time that these two kits were compared. When a kit is uploaded, it will be compared to all the other kits, as far as finding matches, during processing. In some cases, you can see dates when this first Genesis crossover with some of these newer kits happened. You can see the comparison was made back in December. Most likely, this kit was uploaded in December of that year.

Testing Company -- GEDmatch used the first letter of the kit number to indicate the testing company. Since then, they have gone to just random two characters for the first kit number. GEDmatch will actually tell you the testing company used in this column. The old GEDmatch kits used M for 23andMe, A for Ancestry, T for Family Tree DNA, and H for MyHeritage. The new system for all the new uploads this column will tell me the kit is from 23andMe or another company. Be aware that every now and then that some of these kit numbers will be highlighted in green. Whether it’s dark or light green, this green color indicates a new kit uploaded.

GEDmatch Genesis identifies what new kits are available. You want to review your GEDmatch periodically.

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GEDmatch One-to-Many Beta

The GEDmatch Genesis One-to-Many matching comparison does not include all for a lot of customization. You can’t sort the columns or move the entries. To do that, you need to go to another tool -- One-to-Many (Beta). Beta suggests that there are still some bugs that GEDmatch is working out.

However, I’ve used the One-to-Many (Beta) several times. I find it very useful.

When you click on One-to-Many (Beta), you can see it has a completely different user interface. You’re going to your kit number at the top. Then you can filter either autosomal and X. In this case, we want to do autosomal.

You’ll be asked what size you want, whether you want to tag groups, and what you want the overlap cutoff to be.

I use the default search to see a match list. You’ll see that there One-to-Many (Beta) actually has some different columns.

Select -- this column is for visualization options up at the top. It’s only available to tier-one customers. This column gives me an X that I can’t select any of these boxes.

Kit number: this is the same as I described before. If you click the kit hyperlink, then you’ll see a One-to-Many for that kit just like the other one.

Name & Email: Similar to what was described before.

GEDCOM or WikiTree -- this new column displays GEDCOMs or WikiTree profile links. If you find an entry, you can actually see how that person is related based on what they’ve uploaded as far as a GEDCOM. I’ll cover more about GEDCOMs in a future video post.

Age -- this column displays how long a kit has been uploaded. Some of the kits that I manage have been uploaded for about three-six years.

Type -- this column is new to me, and I’m still trying to figure out what this is. I might actually have to email the GEDmatch programmers to figure out what type it is.

Sex of Person, Haplogroups for mtDNA and YDNA -- this column shows male or female or the haplogroups for the different test types. These columns are self-reported by the person that uploaded this kit. Some of the information may be incorrect or outdated.

Total centimorgans -- this column displays the total amount of shared DNA that you have with that person.

Largest centimorgans -- similar to what we saw on the One-to-Many tool before. The difference now is, each one is hyperlinked. The one-to-one tool opens when you click on the link, and you’ll open up a one-to-one comparison.

Generations column -- same as the previous One-to-Many tool

X DNA -- In the beta table, you’re not only examining shared autosomal DNA but also the amount of X DNA that you share with those people.

Source: The company used for the test.

Overlap -- how much overlap there is between those two kits.

GEDmatch Genesis One-to-Many (Beta) Adds Sorting Functionality

The column changes are not dramatic but what you’ll notice is that each column can be sorted alphabetically or reverse alphabetically. You can systematically look at the kits.

If you want to look at the pages with the most recent one on top, you can sort that column.

If you only want to look at matches with a Gedcom or WikiTree, you can sort that column.

You can sort by cMs, Haplogroups, X-DNA, and so on.

Other One-to-Many (Beta) Features

How Many Matches You Can See

You can limit or expand how many matches you see. The default is One-to-Fifty, and you’ll see your matches number one to fifty. You can change that limit to just your top matches or 100 matches.

See Only Matches with More Than a Certain Number of Segments

You change the minimum number size of a segment shared. You can change the number to a larger one, eliminating those matches that only share a smaller segment.

If you have a lot of endogamy, which means family members who are not necessarily close relatives due to cousins' intermarrying, you share a lot of the same DNA. You’ll want to filter the thousands of matches that have small shared segments.

Filter Small Overlaps

Remember I said that the more overlap you have, the better it is for a match. You may want to eliminate some of these smaller kits with an overlap filter.

Give the One-to-Many Tool a Try

In short, GEDmatch Genesis One-to-Many has two tools: the basic that doesn’t allow for sorting and the beta version that allows filtering and sorting.

I would recommend that this is the first place you start when you begin using GEDmatch Genesis. Review your match list and discover which matches you actually already recognize and which ones you may have already matched with through one of the other programs like Ancestry or Family Tree DNA.

This was an overview of the One-to-Many tools on GEDMatch Genesis. If you have any questions, leave them below this post.

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