What qpAdm does
qpAdm is part of ADMIXTOOLS, software widely used in academic studies of ancient ancestry. You give it a target, a short list of candidate sources and a longer list of outgroups. It then asks whether the target relates to the outgroups in the way a mix of those sources would, using f4 statistics computed from genotype data.
The answer is a statistical test. A model with a low p-value is rejected at the chosen threshold. A model that is not rejected remains compatible with those outgroups, but that does not prove it is the true or unique ancestry history. The estimates come with standard errors. Estimates outside 0% to 100% indicate an infeasible mixture and must not be silently removed or clamped.
What a G25 model does
G25 places each sample at a point defined by 25 principal components. A G25 model searches for the percentages of your chosen sources whose weighted average sits closest to your point, and reports the remaining distance. It is fast enough to try hundreds of models, works from a single line of numbers, and shows you visually where you fall among ancient and modern samples.
Its weakness is compression. Twenty five numbers cannot hold everything in a genome, so some different histories end up at the same coordinates, and there is no p-value to warn you. Reading a G25 result well means comparing models, as the guide on admixture calculator accuracy explains.
Side by side
| Aspect | qpAdm | G25 |
|---|---|---|
| What it is | A formal admixture test from the ADMIXTOOLS package | 25 principal component coordinates per sample |
| Input | Genotypes for the target, the sources and an outgroup set | Your 25 coordinates and those of the reference samples |
| Output | Proportions, standard errors and a p-value per model | Proportions and a fit distance per model |
| Speed | Depends on data preparation and the number of models | Seconds per model |
| Main risk | Results depend on the outgroups chosen | Different histories can produce the same coordinates |
| Best for | Testing a specific model rigorously | Exploring many models and seeing where you sit |
What MYDNATLAS offers
The qpAdm Workspace tests models with ADMIXTOOLS 2 using an existing DNA upload. Genotype preparation, allele alignment and reference merging run automatically. Choose one to five sources and more outgroups than sources. Read the estimates, standard errors, p-value and actual SNP and block diagnostics, then download the complete result and configuration. The workspace is included in the paid toolkit and checks the engine and reference availability before accepting a model.
The automatic flow uses a pinned, quality-checked subset of the official AADR v66.p1 Compatibility_HO genotype reference. Your original DNA upload must still be stored, with sufficient usable SNP overlap; a deleted original cannot be reconstructed from G25 coordinates. Already merged EIGENSTRAT files remain available as an advanced option. For coordinates, MYDNATLAS continues to provide Multi-Way Fits for mixtures of 2 to 8 sources, Closest Populations and PCA plots. For ancient G25 sources specifically, see the ancient DNA admixture calculator guide.
If you have a raw DNA file from a testing company, the raw DNA to G25 guide shows how to turn it into coordinates.
Questions
What is the difference between qpAdm and G25?
qpAdm is a formal statistical test: it uses f4 statistics against a set of outgroup populations to ask whether a target can be modelled as a mix of chosen sources, and it returns proportions with standard errors and a p-value. G25 is a set of 25 principal component coordinates; a G25 model finds the mix of sources closest to your coordinates and reports a distance, with no p-value.
Does MYDNATLAS run qpAdm?
Yes. The paid qpAdm Workspace runs ADMIXTOOLS 2 from your existing DNA upload. It checks your SNP identities and alleles, merges compatible calls with the verified AADR genotype reference panel, then tests your chosen sources and outgroups. The original DNA file must still be available and pass overlap and quality checks. Advanced users can also upload already merged ASCII EIGENSTRAT files. G25 coordinates alone cannot provide qpAdm genotypes.
Which one should I pay for?
For exploring your own ancestry and trying many models quickly, G25 is the practical choice. qpAdm is worth commissioning when you need a formal test of a specific model, and only from someone who will show you the outgroups they chose, the p-values and the models that were rejected.
Is there a qpAdm calculator I can run on my raw DNA file?
The MYDNATLAS qpAdm Workspace prepares an existing raw DNA upload automatically, including genotype parsing, allele alignment and merging with compatible reference genotypes. You choose the sources and outgroups. Consumer chips cover only part of the ancient reference panel, so the analysis reports actual overlap and can refuse insufficient data. A G25 admixture calculator works from coordinates instead.
Can G25 and qpAdm disagree?
Yes. G25 compresses the genome into 25 numbers, so a mixture of two populations can land at the same point as an unmixed population that sits between them. qpAdm can sometimes separate those cases because it tests the full set of f4 statistics.