What's the deal?

[Bucko]

Now to complicate the picture, Zinfandel and Primotivo are not exactly the same, but clones according to UC Davis research. Carole Meredith will be published shortly on the true origin of the grape. This from Winespectator.com:

Using DNA profiling techniques, Meredith and two Croatian scientists, Ivan Pejic and Edi Maletic, discovered in December that Zinfandel and an indigenous Croatian grape called Crljenak are one and the same.

The modern search for Zinfandel's roots, so to speak, dates back to the late 1960s. While traveling in Italy, USDA plant pathologist Austin Goheen noticed that the Primitivo grape widely cultivated in the Puglia region bore a strong resemblance to Zinfandel. He brought Primitivo cuttings back to the University of California, Davis, where he was based, for a closer look.

Goheen made his assumption based upon visual criteria, but he could never be sure that Primitivo and Zinfandel were exactly the same variety.

Other later tests backed up Goheen's theory, but a definitive answer didn't come until the 1990s, when Meredith -- a professor of enology and viticulture at UC Davis -- used DNA profiling techniques capable of establishing grapevine identity beyond doubt. Meredith determined that Primitivo and Zinfandel were indeed two clones of the identical variety.

Bucko