Livermore Valley AVA unique east-west orientation, unlike many other winegrowing valleys. Due to a reliable onshore afternoon/evening breeze off of the San Francisco Bay a wide fluctuation in temperature between sites and a large diurnal temperature swing occur. Livermore Valley is considered a Winkler Region III grape growing zone with temperatures comparable to northern Napa Valley appellations such as St. Helena or Calistoga. The relatively obscure Petite Sirah grape produced Livermore's best historically known red wine, although the climate also makes for interesting dessert wines as well as excellent Cabernet Sauvignon, Merlot and Rhone varieties. The original plantings of Sémillon and Sauvignon blanc
Petite mutation and exhibit Mendelian 1:1 segregation. Neutral petites (rho–N): Neutral petite when crossed to wild-type, all offspring are wild-type. It has inherited normal mitochondrial DNA from wild-type parent, which is replicated in the offspring. Suppressive petites (rho–S): crosses between petite and wild-type, all offspring are petite, showing "dominant" behavior to suppress wild-type mitochondrial function. Most petite mutants of "S. cerevisiae" are of a suppressive type, and they differ from neutral petite by affecting the wild-type, although both are a mutation in mitochondrial DNA. Mitochondrial genome of yeast will be the first eukaryotic genome to be understood in terms of both structure