There is a very good video of ystrday's Ridge Winemaker Roundtable on The History of Zinfandel.
Can't figure out the direct link to the video (help if you can), but go to the Ridge home page, RidgeWine.com, scroll all the way to the bottom, click on the Facebook icon takes you to the Ridge Facebook page, then scroll down to the Videos, then click on The History of Zinfandel video.
Runs a bit over an hour. Usual suspects: MarkVernon/DaveGates/EricBauer/JohnOlney. Special guest is CaroleMeredith who appears to know something about the grape... at least she talks a good story!!
Near the end, she gives a very good discussion on varieties and clones.
Well worth the hour to view. I learned so new things.
Tom