title: Isolation and characterization of microsatellite loci inSorbus porrigentiformisand cross-amplification inS. ariaandS. rupicola(Rosaceae).
abstract: OBJECTIVE
  Southwestern Britain is an emblematic hotspot of polyploid diversity of whitebeams (Sorbus ariaagg.; Rosaceae) with ca. 30 polyploid endemic species. The tetraploidS. porrigentiformisis postulated as one of the parents of most of these endemics, along with the sexual diploidS. arias. str. and the tetraploidS. rupicola.
  
  
  RESULTS
  We isolated 16 nuclear microsatellite loci fromS. porrigentiformisand characterized them on 45 trees representing the three putative parental species. Eleven loci were polymorphic, and eight of them exhibited species-specific alleles. Allele numbers ranged from one to 11, and observed heterozygosity ranged from 0.40 to 1.00. The intraspecific levels of variation were very low, in agreement with the facultative apomictic reproduction hypothesized for this species.
  
  
  CONCLUSIONS
  The species-specific alleles will be useful for tracing the origin of the narrowly distributedSorbustaxa. In addition, the assessment of diversity levels will help design a conservation strategy for the polyploid complex.
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom.
authors.forename: Rosalía
authors.initials: R
authors.lastname: Piñeiro
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom.
authors.forename: Freja
authors.initials: F
authors.lastname: Karrman-Bailey
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom.
authors.forename: Robyn S
authors.initials: RS
authors.lastname: Cowan
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom; School of Plant Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Fay
keywords: British whitebeams; Rosaceae; Sorbus porrigentiformis; conservation; nuclear microsatellites; polyploid evolution