Natural Hybridization in Saxifraga callosa Sm.

F. Grassi; M. Labra; L. Minuto; G. Casazza; F. Sala

doi:10.1055/s-2005-873047

Plant Biology, Table of Contents

Plant Biol (Stuttg) 2006; 8(2): 243-252
DOI: 10.1055/s-2005-873047

Research Paper

Georg Thieme Verlag Stuttgart KG · New York

Natural Hybridization in Saxifraga callosa Sm.

F. Grassi¹ , M. Labra² , L. Minuto³ , G. Casazza³ , F. Sala¹ ^, ⁴

¹Botanical Garden, Department of Biology, University of Milan, Via Celoria 26, Milan, Italy
²DISAT, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy
³DIP.TE.RIS, University of Genova, Corso Dogali 1M, 16136 Genova, Italy
⁴CNR, IBF, Via Celoria 26, Milan, Italy

Abstract

Saxifraga callosa Sm. is an evergreen perennial species distributed from Eastern Spain, through the Western Alps and the Apennines, to southern Italy. The existence of high morphological variation within different subspecies indicates that phenotypic characters are useful but not sufficient taxonomic tools. Indeed, available morphological data already suggested that S. callosa subentity lantoscana may be an outcross between S. callosa and S. cochlearis. In this work, by analyzing ITS (Internal Transcribed Sequences), AFLP (Amplified Fragment Length Polymorphisms), and cpDNA (chloroplast DNA) markers, a comprehensive study of the genomic relationships among S. callosa and related species has been carried out. The sequence of the ITS region of S. callosa subentity lantoscana gave no conclusive results on the taxonomy status of S. callosa subentity lantoscana. On the other hand, the use of the “NewHybrids” software to analyze an AFLP data-set (208 polymorphic amplified fragments) supported a significant posterior probability that S. callosa subentity lantoscana individuals are natural hybrids between S. callosa and S. cochlearis. The level of introgression of genes from alien genomes was confirmed by a simpler and quick methodology that analyze length variation in cpDNA sequences.

Key words

AFLP - introgression - ITS - hybridization - morphology - Saxifraga callosa - Saxifraga cochlearis - TrnL.

Full Text

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F. Grassi

Botanical Garden
Department of Biology
University of Milan

Via Celoria 26

20133 Milano

Italy

Email: fabrizio.grassi@unimi.it

Editor: M. Koornneef