The confusion was caused not by poor analysis but limited data.
Indeed, one of Dr Chen`s own papers provided evidence for the 400,000 year figure, based on some 70 varieties of wild grapes from a small region of Germany.
His new work tramples over such limitations by including over 3,500 varieties from the full terroir of existing viticulture: 1,000 or so wild; the remainder cultivated.
Getting hold of that many samples was not easy. Dr Chen`s team relied on the good will of collaborators, enthused by the prospect of participating in a definitive study with generous funding, provided mostly by Chinese scientific bodies.
Kristina Margaryan, of the Institute of Molecular Biology in Armenia, for instance, spent weeks trekking with colleagues through her country`s hills, collecting what would later turn out to be hundreds of hitherto unknown varieties of wild grape.