title: The genetic ghost of an invasion past: colonization and extinction revealed by historical hybridization in Senecio.
abstract: Hybridization is an important evolutionary factor in the diversification of many plant and animal species. Of particular interest is that historical hybridization resulting in the origin of new species or introgressants has occurred between species now geographically separated by great distances. Here, we report that Senecio massaicus, a tetraploid species native to Morocco and the Canary Islands, contains genetic material of two distinct, geographically separated lineages: a Mediterranean lineage and a mainly southern African lineage. A time-calibrated internal transcribed spacer phylogeny indicates that the hybridization event took place up to 6.18 Ma. Because the southern African lineage has never been recorded from Morocco or the Canary Islands, we hypothesize that it reached this area in the distant past, but never became permanently established. Interestingly, the southern African lineage includes S. inaequidens, a highly invasive species that has recently become widespread throughout Europe and was introduced at the end of the 19th century as a 'wool alien'. Our results suggest that this more recent invasion of Europe by S. inaequidens represents the second arrival of this lineage into the region.
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand. pieter.pelser@canterbury.ac.nz
authors.forename: Pieter B
authors.initials: PB
authors.lastname: Pelser
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Abbott
authors.forename: Hans P
authors.initials: HP
authors.lastname: Comes
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Milton
authors.forename: Michael
authors.initials: M
authors.lastname: Möller
authors.forename: Mark E
authors.initials: ME
authors.lastname: Looseley
authors.forename: Glynis V
authors.initials: GV
authors.lastname: Cron
authors.forename: Julie F
authors.initials: JF
authors.lastname: Barcelona
authors.forename: Aaron H
authors.initials: AH
authors.lastname: Kennedy
authors.forename: Linda E
authors.initials: LE
authors.lastname: Watson
authors.forename: Rubén
authors.initials: R
authors.lastname: Barone
authors.forename: Fabián
authors.initials: F
authors.lastname: Hernández
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Kadereit
mesh_terms: D000353:Africa, Southern; D000595:Amino Acid Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D053476:Extinction, Biological; D014644:Genetic Variation; D006824:Hybridization, Genetic; D058865:Introduced Species; D008969:Molecular Sequence Data; D009018:Morocco; D010802:Phylogeny; D058974:Phylogeography; D011995:Recombination, Genetic; D012674:Senecio / Q000145:classification* / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013030:Spain
chemical_list: D018744:DNA, Plant