Frequently asked questions

Why two different trees?

New to this subject, and notice a discrepancy between your ISOGG-based and experimental-based prediction? Go with the ISOGG-based prediction.

The experimental tree is intended to help lighten the workload of ISOGG volunteers. So please kindly refrain from asking ISOGG volunteers to explain why discrepancies between the two trees exist. Here are some reasons:

The experimental tree aims to build on the ISOGG tree. The experimental tree is computer-generated, using an experimental algorithm. The algorithm may still require some fine-tuning. Unlike the ISOGG tree, the experimental tree does not draw from non-Geno datasets, or from the STR data associated with Geno-tested kits.

The ISOGG tree is subject to far greater scrutiny. ISOGG's tree does not include "private" SNPs -- those known to only define twigs on the Y-tree. Nor does the ISOGG tree include SNPs whose positions are still approximate. The nomenclature is also more stable.

Trying to make sense of your Geno 2.0 or Full Y-chromosomal results, and facing a list of dozens of unfamiliar SNP calls? It is helpful to know which of the approximately-placed SNPs have already been observed in your "Y-SNP neighbourhood", and which ones are truly novel. The tools provided by this website help you focus your investigation on a short-list of SNPs. The prediction based on the experimental tree will give you a shorter short-list. Some of these short-list SNPs may define your twig or leaf on the human Y-tree.

Once again, if in doubt, go with the ISOGG-based prediction.

What is this site's relation with ISOGG?

ISOGG's volunteers commendably maintain an up-to-date and high-quality Y-tree, free of charge. provides a tool for making sense of data-intensive broad-spectrum Y-SNP tests, using ISOGG's tree as an input in this analysis. is not run by ISOGG, nor is sponsored or endorsed by ISOGG. Nor does ISOGG endorse the experimental Y-tree (ISOGG does not even expressly endorse its own Y-tree).

The Y-SNP Subclade Predictor and experimental Y phylogeny are copyright © 2013-2024 Chris Morley. All rights reserved. Licensed for non-commercial use under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported license, with the additional condition that the underlying experimental Y phylogeny cannot be used in other prediction/classification software without the author's prior permission. Genetic genealogical consultants, businesses and others looking to use the predictor and/or experimental phylogeny as part of a for-profit activity must contact the author to discuss licensing. Visitors relying on any information do so at their own risk. Use of this service is subject to this privacy policy