title: Tracking ancient polyploids: a retroposon insertion reveals an extinct diploid ancestor in the polyploid origin of belladonna.
abstract: Polyploidy is a prominent process in plant evolution and adaptation, but molecular phylogenetic studies of polyploids based on DNA sequences have often been confounded by their complex gene and genome histories. We report here a retroposon insertion in the nuclear gene granule-bound starch synthase I (GBSSI or "waxy") that clearly reveals the ancient hybrid history of the medically important polyploid species belladonna (Atropa belladonna) and resolves the controversy over the taxonomic group to which it belongs, the tribe Hyoscyameae (Solanaceae). Our inferences based on the pattern of presence or absence of the retroposon insertion are corroborated by phylogenetic analyses of the GBSSI gene sequences. This case may suggest that retroposons are promising molecular markers to study polyploid evolution.
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors.forename: Yao-wu
authors.initials: YW
authors.lastname: Yuan
authors.forename: Zhi-yun
authors.initials: ZY
authors.lastname: Zhang
authors.forename: Zhi-duan
authors.initials: ZD
authors.lastname: Chen
authors.forename: Richard G
authors.initials: RG
authors.lastname: Olmstead
mesh_terms: D001532:Atropa belladonna / Q000235:genetics*; D004171:Diploidy; D019143:Evolution, Molecular; D053476:Extinction, Biological; D018628:Gene Dosage / Q000502:physiology; D016254:Mutagenesis, Insertional / Q000502:physiology*; D010802:Phylogeny; D011123:Polyploidy; D018626:Retroelements / Q000502:physiology*; D019657:Solanaceae / Q000235:genetics
chemical_list: D018626:Retroelements