## 1 Introduction  
_Saccharomyces cerevisiae_ represents the yeast mainly responsible for alcoholic fermentation in wine. The use of _S. cerevisiae_ commercial active dry wine yeasts drives a vigorous fermentation process linked to a rapid start of fermentation and a complete consumption of fermentable sugars [1], ensuring uniform and constant quality of the wine over the time. On the other hand, pure fermentation could lead the loss of aromatic variability, complexity, and sensorial varietal aroma of wines [2]. Moreover, the widely use of commercial yeasts contrast with the growing interest for organic and natural wines, a new relevant trend in the wine sector. For this reason, a great interest of winemakers is addressed through the use of indigenous _S. cerevisiae_ yeasts. They are new yeasts with unknown new genotypes and characterized by a specific secondary metabolite profile. A suitable strategy to detect new _S. cerevisiae_ strains is to carry out a sampling campaign of isolation in their natural ecosystem such as vineyard [3] or cellar environments. In the latter case, it is better to choose collars that never use active dry yeasts to avoid contamination by commercial starters.  
Indigenous yeasts in their natural ecological niches are well adapted to climatic conditions and grape varieties surviving during winemaking practices of a specific wine-growing area [4] with a possible enhancement in the typicity of wines. In this picture, spontaneous wine fermentation conducted by several indigenous _S. cerevisiae_ strains, and also indigenous non-_Saccharomyces_ yeasts, may be a way to obtain distinctive aromatic profile of wine. It has been widely demonstrated that, although different indigenous _S. cerevisiae_ strains are involved in the process, only a few strains represent the dominant population of the fermentation process [5; 6; 7; 8]. This advantage could be related to the highest competitivity of the dominant yeasts to survive under oenological conditions such as increasing ethanol concentrations, low pH values, temperature variations and cell-to-cell interactions with other yeasts [9; 10]. Another feature of indigenous yeasts is the so called \"winery effect\" meaning that some indigenous _S. cerevisiae_ strains may persist in the same winery for several consecutive years characterizing the wines of the territory [7; 8; 11]. This is probably due to the better adaptation of these resident yeasts to a specific winery's winemaking managements, including climate and agricultural practices. They may play a relevant role in determining organoleptic properties of the wines, which also related to the specific winery [7]. These aspects may reinforce the relationship between the provenience of indigenous _S. cerevisiae_ strains and the aroma profile of the resulting wine [12]. On the contrary, [PERSON] and co-workers [4] found that there are no representative strains from the winery or the area in the long term (3-4 consecutive years) when investigating the biodiversity of native _S. cerevisiae_ in 11 wineries.  
In this work, the occurrence and persistence of _S. cerevisiae_ populations of two wineries situated within the Verdicchio DOC winemaking area (distant c.a. 20 Km) was investigated with the aim of increasing knowledge on genetic variability of indigenous _S. cerevisiae_ populations in relation to a specific winery, known as the \"winery effect\", and their contribution on the typicity of wine. Both wineries never used commercial wine strains, and instead employed spontaneous fermentations of a pre-inoculum (\"_pied de cuee_\") that involved collecting grapes a few days before harvest and fermenting must in a reduced volume to induce and control the alcoholic fermentation which is then used to inoculate successive bathes of must. The isolated _S. cerevisiae_ strains were bio-typed and oenologically characterized to evaluate the relation among origin, biotype, and oenological characters.