Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 1.29

PLANT PHYLOGEOGRAPHY BASED ON ORGANELLE MARKERS: SOME CASE STUDIES ON MEDITERRANEAN TREE SPECIES

FINESCHI S.*, PETIT R.J.**, ANZIDEI M.***, CARNEVALE S.***, PASTORELLI R.***, SALVINI D.*, TAURCHINI D.*, VENDRAMIN G.G.***

*) CNR Istituto di Biologia Agro-Ambientale e Forestale, Porano -TR

**) INRA Laboratoire de Génétique et Amélioration des Arbres Forestiers, Gazinet, France

***) CNR Istituto Miglioramento Genetico Piante Forestali, Firenze

phylogeography, chloroplast markers, Mediterranean forest trees

Plants have unique biological attributes and a central place in ecosystems of great interest to researchers investigating population dynamics. Chloroplast DNA variation has been used extensively to construct interspecific phylogenies. Early studies of plant organelle revealed low levels of intraspecific variation: as a consequence, plant organelle DNA was considered not sufficiently informative for intraspecific studies. Progresses in molecular organelle genetics have provided insights into the features of organelle genomes (structure, variation, inheritance) that influence the generation of variation used in phylogenies. Several factors may influence the structure of the geographic distribution of plant organelle markers (gene flow within and between species, dispersal, history and selection). Organelle markers can provide useful insights into these processes, including many that are unique to plants. Phylogeographic studies can offer essential background information to unravel current from past processes, understand the consequences of crucial events such as colonisation in the life and longevity of plant species, and to test hypothesis on adaptation. To achieve this it is essential to consider life history traits and the genetic system itself. Chloroplast markers were used to study the phylogeography of some Mediterranean forest tree species, characterised by different geographic distribution and different life history traits. This presentation will focus on two Sicilian endemism, Zelkova sicula and Abies nebrodensis , and on Sicilian populations of a widespread species, Quercus ilex . Chloroplast markers allowed unravelling the history of these tree species in Sicily. Moreover, information obtained in these studies can be used in conservation and management of genetic resources and permit the identification of key regions deserving priority for conservation. Results showing the role played by life history traits of different forest species on the geographic distribution of haplotypic diversity will be provided and discussed.