Do GEDmatch Superkits Give You More DNA Matches Than Non-Superkits?
Have you been wondering whether or not GEDmatch Superkits will give you more matches? Wonder no more.
On Facebook, I recently discussed with somebody about Superkits and the matches you get for them. The discussion eventually considered whether or not GEDmatch Superkits provide you with more DNA matches.
I decided to try and see whether or not those Superkits would give you more matches.
What is a Superkit?
A GEDmatch Superkit is a combination of two or more DNA kits. Basically, if you've tested with any two genetic genealogy companies (23andMe, Ancestry DNA, Family Tree DNA, MyHeritage DNA, or Living DNA), you can combine your DNA data into one kit. This results in more SNPs.
Perhaps you tested with Ancestry DNA, 23andMe, and MyHeritage. Each kit has a different set of SNPs, but some of those SNPs overlap.
For instance, perhaps we number our SNPs 1 - 10. Then we record the different SNPs that each one of these companies has. Perhaps:
Ancestry has SNPs 1, 2, 4, 6, 7, and 9.
23andMe has SNPs 2, 3, 4, 6, 7, 8, 10.
MyHeritage has SNPs 1, 2, 3, 5, 6, 8, 9, 10
By combing the kit results together, we create a Superkit, but only on GEDmatch.
As we compare the results from each company, we do find coverage for SNP 1-10. Even though each one of these kits individually doesn't have that many SNPs, our Superkit ends up with all 10 SNPs.
The nice thing that the GEDMatch Superkit does is for instances where you have multiple copies of the SNP. The tool will have more than one place to verify against itself.
If the SNPs between each company conflict, then GEDmatch will not use that data because it can't determine which one is correct.
However, we end up having a kit with more SNPs in our Superkit than in any individual kits.
Be sure to listen as I explain the problems more fully in this video.
Will You See More DNA Matches with a Superkit?
This is something that we can look at based on actual data. I have tested with multiple companies, and I have made multiple different types of Superkits. In the video above, I show you the data and explain what I found.
I did find some discrepancies when I combined different kits from the various commercial genetic genealogy companies I have tested with.
Why do the discrepancies in SNP totals occur?
Perhaps it depends on how GEDmatch has interpreted the different SNPs.
When GEDmatch was originally created, only 23andMe and Family Tree DNA were commercially available. As such, GEDmatch was initially created to compare kits from those companies. It makes sense that 23andMe and Family Tree DNA are roughly equivalent as far as the number of SNPs.
However, if you tested with 23andMe before 2017, you're going to have an older chip version, which means you're Superkit will have fewer SNPs for comparison.
I believe MyHeritage and Family Tree DNA use the same chip since the MyHeritage DNA is processed at Family Tree DNA labs. As such, I noticed a small fraction of MyHeritage SNPs that were different from the Family Tree DNA kit.
So, I can understand why 23andMe, MyHeritage, and Family Tree DNA have roughly the same amount of matches in GEDmatch.
With Ancestry, the GEDmatch database is not optimized for that Ancestry kit. A significant amount of the SNPs that Ancestry tests find are not part of the GEDmatch database. As such, some of the data is lost.
With Living DNA, they are using the new processing chip. Sometimes, the number of SNPs is in line with Family Tree DNA, MyHeritage, and 23andMe. But in some instances, it has less than half the total number of SNPs.
I believe the variation between the older and newer chips accounts for different SNPs and DNA match totals.
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Will you get more matches?
It depends on how you create your Superkit.
If you are using that 23andMe version 3 test as the baseline, then you're probably going to get maybe 10% percent fewer matches.
If you're using your Ancestry as the main kit with one other kit, then you might be getting significantly fewer matches.
With my experiments, I have seen that other than the Ancestry kit, both of my Superkits have fewer matches than any one of the other testing kits.
When it comes to whether or not you're going to get matches that are 20 centimorgans or more, what I find is there's actually very little difference between these Superkits.
So while you may get fewer matches, it doesn't look like you're going to get significantly fewer of those matches that are of the higher CM amounts.
To sum up, what you're doing with a GEDmatch Superkit is eliminating many false matches or matches that are marginal. Whereas, with DNA matches that share more than 20 centimorgans, those will be solidified.
Such matches are so long and have many SNPs involved, so adding more SNPs has a very low likelihood of turning that into "Not a Match" or removing that match from your list.
Hopefully, that answers your questions about how the GEDmatch Superkit affects the number of DNA matches you receive.
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