Biodiversity of Brassicaceae in medieval landfills of Emilia Romagna (Northern Italy); archaeobotanical and genetic analysis (aDNA)

The records of Brassicaceae in archaeological sites of Emilia Romagna Region are rather scarce at Roman Period, while increasing in the Middle Ages (10th – 15th cent. AD). Indeed, many seeds of Brassica sp.pl. (approximately from 10 to 1500 seeds per liter) were recovered from garbage of kitchen, garden or craft activities (unpublished data) from two urban sites (Ferrara and Lugo, near Ravenna). Archeobotanical seeds were identified (Brassica cf. juncea, B. napus, B. nigra, B. cf. oleracea, B. rapa) and then analyzed to find any traces of aDNA (by Simona De Felice during PhD of Aberystwyth University, UK) using several precautionary measures to prevent exogenous contamination: a) seeds with unbroken integument were treated with UV light to break and immobilize any contaminant DNA present on seed coat surface; b) DNA extractions were made on internal seed tissues that had been isolated from their surrounding seed coat under a sterile dissecting microscope; c) DNA extractions and PCR (Polymerase Chain Reaction) were performed under sterile conditions (sterilized laminar flow hood), using pipettes with filter tips and in a different building from that where modern Brassica samples were routinely analysed. In total DNA of 325 seeds was extracted an approximately a third (98) of such samples were able to generate sequences. The results of genetic analysis confirm the Brassica genus to 97%, with a dominance of B. nigra