Applicazione della tecnica del DNA-barcoding alle conifere italiane
Author(s)
Armenise, Laura
Date Issued
March 11, 2011
Type
Doctoral Thesis
Abstract
DNA barcoding is a technique for characterizing species of organisms using a short DNA sequence from a standard and agreed-upon position in the genome. It differs from molecular phylogeny in that the main goal is not to determine classification but to identify an unknown sample in terms of a known classification.
Forests play a crucial role in self-sustaining of natural ecosystems and human environment at both local and regional scales. Conifers constitute over 39% of the world’s forests and are highly exposed to threats and exploited at high frequency. They have an urgent need to be identified through DNA barcodes, but received little attention up to date. Currently, conifer DNA barcoding is greatly impeded by low rates of successful species identification and a lack of consensus on the selection of markers.
We examined whether four marker regions (trnh-psba, rbcL, rpoc1, matK) matched conifer species taxonomy in a practical biodiversity survey of Italian forested land. Our objective was to provide a test of future in situ applications of DNA barcodes by evaluating the efficacy of species discrimination under the criteria of uniformity of methods and natural co-occurrence of the species.
Twenty-five conifer species (62 individuals) were included in a floristic study based on regional sampling. Methods based on genetic distances, similarities and phylogeny were used to assess identification of taxa and species monophyly. We obtained 100% total discrimination success, with rbcL+trnH-psbA as the suggested two-locus barcode in terms of efficiency and universality. Consistent barcoding gaps, supported monophyly and regional patterns of diversity were evidenced in most cases.
It’s possible to conclude that the time is ready for the application in practice of barcoding campaigns at national levels: the conifers national database recovered can be efficiently used to compile biodiversity surveys in local floras and can be easily repeated even by non-taxonomist specialists, for identification of native, naturalized or ornamental species. The dataset of conifers DNA sequences achieved, may have relevant outcomes for future studies and applications in forest ecosystems, such as in the advancement of community ecology studies and local biodiversity surveys.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
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