Reticulate phylogeny in the genus Sorbus: the case of Sorbus haljamovae Bernátová et Májovský

Abstract

Phylogenetic relationships between diploid sexual species S. aria and S. chamaemespilus and their putative alloploid hybrid S. haljamovae were studied on 8 localities in Central Slovakia. Six polymorphic chloroplast microsatellite markers were used to infer polymorphism levels in parental taxa and direction of hybridization. Six haplotypes were identified in the analyzed material. Haplotype 2 was found exclusively in S. chamaemespilus, which was found to be completely monomorphic. Haplotypes 1 and 4 were found only in S. aria, haplotypes 3 and 5 were shared by S. aria and S. haljamovae. A single specimen of S. aucuparia, used as outgroup in the phylogenetic analysis, contained a specific, highly divergent haplotype. Based on these results, we suggest that S. haljamovae is a polyphyletic taxon originating from at least two independent hybridization events.