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Recreate Your Ancestor’s DNA with the GEDmatch Lazarus Tool

Use Lazarus Tool to recreate your ancestors DNA with chromosome painting

We all have relatives who’ve passed away before taking a DNA test. Discover how with GEDMatch’s Lazarus tool can recreate your decease ancestor’s DNA.

Commercial DNA testing has been around for almost twenty years but only about ten years for genealogical purposes. We’ve had lots of relatives who may have been interested in genealogy or may have wanted to support a genealogy hobby during that time, but they passed away without taking a DNA test.

Thanks to GEDmatch’s Lazara Tool, you may be able to piece together their DNA and discover more matches.

How much of your ancestor’s DNA could you recreate?

Navigate to the GEDmatch Lazarus tool page. You’ll need to input information about matches that this person has to allow the tool to piece together DNA segments from the different matches.

If you want to read more about Lazarus and how it works, click on the GEDmatch Wiki link from this page (only accessible after you log in to GEDmatch).

For this to work, you will compare DNA kits related to the common ancestor whose DNA you’re attempting to recreate.

Use the Lazarus Tool to recreate the DNA of your deceased ancestor. #gedmatch #geneticgenealogy #dna

The first step to recreating your deceased ancestor’s DNA.

Begin Completing the Lazarus Tool Form

In the video, I use my dad’s DNA to recreate the DNA of a paternal ancestor.

Since my father is male, I select the appropriate option. Selecting the gender of the test taker comes into play because the tool needs to know if the kit has one X chromosome or two.

For the cM threshold for segments to make a new kit, I recommend using the default of six centimorgans. You can adjust the number depending on your family situation, for instance.

If you have endogamy in your family tree, you’re probably going to want to increase that to 12 or even 15 centimorgans.

If you want to explore some speculative segments, you might want to lower that number.

By sticking with six or seven centimorgans, you’ll have sufficient results for your needs.

Which process should you use with the GEDmatch Lazarus Tool to recreate the DNA of your deceased ancestor. #gedmatch #geneticgenealogy #dna

Which processing option is best for your Lazarus Kit?

Which processing option should you select for your Lazarus Kit?

  1. “Trial Run” option -- this lets you know if that kit has enough information to use the Lazarus tool successfully.

  2. “No batch processing” option -- this allows you to do one-to-one matches, but it won’t allow you to do one too many matches.

  3. “Full processing” option -- this uses the one-to-many comparison.

When you first explore the Lazarus tool, stick with the trial runs or the no batch processing until you can create a good kit that has enough to make the one-to-many comparisons. Then run the full processing option.

Enter Kits for Lazarus Tool

Group Zero (0ptional)

Notice that Group Zero is optional. You’ll enter kits, if you have them, of the deceased ancestor’s spouse. If you’re trying to recreate your father’s DNA, you will enter the kit number for your mother (if she has taken a DNA test).

If the spouse has not tested, then enter kit numbers for the spouse's biological relatives but not the focal ancestor.

For instance, you could enter the kit for a maternal aunt or maternal cousins if your focal ancestor is your father.

Group One

For the Lazarus tool to work, you need to have at least one entry in Group One. Group One includes the descendants of the target person. If you’re recreating your father's DNA, you would add kit numbers for his children, his grandchildren, or great-grandchildren.

Be aware. You don’t need to add the grandchild's kit number if you enter that grandchild’s parent’s DNA kit number into Group One.

For instance, if you only had four siblings and have taken DNA tests, you don’t have to input the kit numbers for your children or your nieces and nephews.

You would only add your father’s grandchildren's DNA if you do not have their parent’s DNA.

Ideally, you want to have all lines of descent represented, but you can still use this tool if you only have one child’s DNA.

Group Two

This group consists of people related to your target person but are not descendants of your target person. This would include the target person’s siblings, aunts, uncles, or nieces and nephews (no matter how ‘great’ or far removed).

This group ALSO includes your target person’s DNA matches that you have not established how they are related. In other words, your target ancestor’s Match List of distant relatives can go into Group Two.

If you lack many known relationships on your DNA match list, you’ll want to add as many people to Group Two as possible.

VIDEO: GEDmatch Lazarus Tool

Watch this video on YouTube.

Generate Your Lazarus Kit and Recreate Your Ancestor’s DNA

After you have added the DNA kit numbers to Group One and Two (and zero if you can), then press the “Generate” button to create your Lazarus kit.

GEDmatch is going to go through and analyze the data you’ve given it. This may take some time.

It will generate a table of all the matching segments between the kits in Group 1 and the kits in Group 2. The more people you put into Group 1 and Group 2, the larger the table will be.

The next thing the page has is a Group 0 segments table. This table compares Group 0 to Group 2, and it is finding any segments in common that it can remove.

The 3rd table here is the resulting Lazarus segments. These are the segments of DNA that have now been added to the new kit. Some segments may be large, but others may be small.

Overall, the kit I made had 3,558.7 centimorgans, which is close to the best you will get. The best Lazarus kits are in the range of 3,000 to 3,500 centimorgans, though having more centimorgans is possible, as in my case.

The final table on the page is which kits match with which segment on the Lazarus kit. It’s just the same table as above but sorted by location on the chromosomes.

Save Your Lazarus Kit

When you’re creating a Lazarus kit, this is the only time you’re ever going to be able to see this information, so you might want to save all of it on to a spreadsheet in case you want to look at any of this information. There’s no way to go back to this information or find it again.

At the bottom of the Lazarus generator tool page, there is the opportunity to download this file of people. This is not a file of all this information on this page but is instead the data file used to create the Lazarus kit.

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Points to Remember When Recreating Your Ancestor’s DNA

Before I end, let me reiterate a couple of things that I think are really important when dealing with Lazarus kits.

First off, this Lazarus kit that you create at best is only going to recreate about 50 percent of the DNA. That DNA is not going to be separated into paternal chromosomes or maternal chromosomes. It’s all going to be mixed together.

Additionally, keeping in mind whenever you match with a Lazarus kit is just a clue. There is a much greater possibility that matches with Lazarus kits are false matches than with another DNA kit. That is because those matches may actually be spanning part of a paternal chromosome and part of it of a maternal chromosome, which is all looking like one thing on the Lazarus kit. There’s no way to start to distinguish those in a Lazarus kit.

Also, keep in mind the diminishing returns I mentioned in the last half of my video (watch it to understand better). If you have more than four children, you’re not going to see much of a difference in the Lazarus kit. If you go beyond about a hundred distant cousins, you’re not going to see much of a difference in the Lazarus kit. But getting from 20 distant cousins to a hundred distant cousins can actually have a significant amount of DNA added to that Lazarus kit.

Finally, if you don’t have close relationships, like children, parents, and siblings, then it is unlikely that you’re going to be able to create a kit that has enough DNA to use the one-to-many matching.

Unfortunately, Lazarus is not going to be able to recreate all of a target person’s DNA. However, it’s certainly better than nothing, and I would encourage you to try it and see how much you can create.

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