Genealogy with DNA Discussion Group Meets on Wednesday Dec 4 at Noon

if you plan to do research at your FHC, bring a thumbdrive!

IMPUTE: assign a value to something by inference from the value of the products or processes to which it contributes.

IMPUTATION in Genetics: using statistical inference to deduce unknown genotypes based on known ones. Genotype imputation is usually performed on SNPs, the most common kind of genetic variation.

IMPUTATION is the process whereby your DNA is tested and then the results “expanded” by inferring results for additional locations, meaning locations that haven’t been tested, by using information from results you do have. In other words, the DNA is adjacent locations is predicted, or imputed, by their association with their traveling companions. In DNA, traveling companions are often known to travel together, but not always. From DNAeXplained.

How does this relate to me? Some DNA testing companies allow you to upload your DNA DATA file generated at another company. For example, Family Tree DNA will accept DATA files from 23andMe as input to their Family Finder product. The price for this service is lower than if you took the “spit test” obviously because they do not have to mail kits and do the processing required to sequence the DNA.

But, there is a “gotcha” here. The different companies do not all use the same chips nor sample the same SNP locations. They also upgrade their own chips periodically. To be able to be backward compatible and to provide MATCHING services, they need to “equalize” the data enough so they will be reasonably accurate. This is fine except when chromosome browsers are used to compare segments.

My view is to remember your purpose. If you are after accuracy above all else, then spend the extra money to get the “spit test”. But if you just want to broaden your cousin match pool, by all means try uploading your data somewhere else at the discounted pricing.

An example of how we used data uploads. Sisters A & B had tested at FTDNA. Sister C had tested at 23andMe. In order to get all 3 sisters together, we downloaded sister C data from 23andMe and then uploaded it into FTDNA for only $19.

AncestryDNA and 23andMe do NOT accept DNA data uploads, the other companies do. I recommend testing at one of these companies, downloading the data and uploading elsewhere. Unless, like me, you want purity everywhere. 🙂

Let’s discuss it.


”I hate when people accuse me of lolly gagging when I’m quite clearly dilly dallying.” – Rebelsmarket


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