None of these factors makes the Population Y signal simply an artifact.

Multiple studies using different methods and different datasets have found signals consistent with Population Y, and the consistency across different approaches is one reason the finding is taken seriously.

But the variability in results means that the signal is not as robust or as clearly quantified as it would be if all studies found it at the same intensity using the same methods.

This variability is itself scientifically informative: it suggests that the Population Y signal, if real, is a subtle one — a small contribution to the ancestry of some populations rather than a dominant component — and that resolving its nature will require larger datasets, better-preserved ancient specimens, and more carefully calibrated analytical methods than have been available to date.