Y-SNP Subclade Predictor: extract Y-DNA from an autosomal test (preprocessing stage 1 of 2)

Some autosomal genetic genealogy tests (such as 23andMe, AncestryDNA and MyHeritage – but not Family Finder) also contain a few hundred Y-DNA markers. The Y-DNA data from these tests is of lower quality, but may still suffice for a very, very general Y-DNA haplogroup classification.

This is useful if you need to make a very basic Y-DNA comparison between two men: if for instance one man is R1b and the other man is I1, then you can be certain their patrilineal connection is not genealogically significant. If both men have the same high-level classification then they will need further Y-DNA testing to confirm a recent patrilineal connection.


  • Only half the population has a Y chromosome. This tool will produce dubious results if your test subject is female.
  • The pre-processing script (step 3) has not been tested on mobile devices. At present I cannot guarantee that your phone is powerful enough to run it. Consequently, there is a risk of your mobile browser freezing or crashing. It is also not easy for iOS and Android devices to handle downloaded files without involving a third-party cloud storage service.
  • The Y-SNP Subclade Predictor was tuned for Geno 2.0 data. Your autosomal test has a far more limited offering of Y-SNPs. The predictor needs to be tuned for data like yours, and the underlying list of SNP aliases needs to be updated, but I don't have time at the moment for these tasks. It is going to take some extra effort on your part to assess each proposed classification.
  • Despite the predictor not being intended to handle your type of data, it is frequently used for this purpose. So I might as well provide an online Y-DNA extraction tool to streamline your work. I will only provide minimal support for this extraction tool and the subclade predictions resulting from it.
  • Please ignore predictions very close to the haplotree trunk, such as BT. This is a consequence of the predictor not being tuned for your type of data.
  • I want to stress that your predicted classification is only very, very general. If, for instance, you receive a classification that is no more specific than R1b, you are very likely not basal R1b. Rather, you are far more likely to belong to some subclade of R1b that your testing company overlooked or did not know about.


  1. Visit your testing company's website and download your raw results file:
  2. To consent to this service, tick the checkbox below.
  3. Click the "Choose File" button below and select the file downloaded in step 1. (Your web browser may give this button a different caption, such as "Browse...".)
  4. Your web browser will run my pre-processing script – no further software is required. This script extracts Y-DNA calls and generates a summary of your test's chromosomal coverage. The particulars for the rest of your chromosomes are ignored. Since this script runs on your device, my service never sees your autosomal DNA data.
  5. Review your Y-DNA data and metadata, and then click "Submit".
  6. Your Y-DNA data and metadata will be sent to my server, to be converted to a format that the Y-SNP subclade predictor can handle.
  7. If there are no error messages, click on the "Feed this data into the Y-SNP Subclade Predictor" link. This will populate the main form with your extracted Y-SNP data.
  8. Complete the "I'm not a robot" challenge questions. I suggest you use the main form's default settings: "FTDNA format (transferred Geno 2.0 results)" as the data format, and "Experimental tree" as the tree version.

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