2014. július 23., szerda
Cikk az Annals of Botany c. folyóiratban
Az Annals of Botany című folyóirat elfogadta közlésre a 'Molecular phylogeny and evolutionary history of the Eurasiatic orchid genus Himantoglossum s.l. (Orchidaceae)' című cikkünket (szerzők: Sramkó G. – Molnár V. A. - Hawkins J. A. - Bateman R. B.).
• Background and Aims All putative species of the charismatic orchid genus Himantoglossum s.l. were sampled across its geographical range in order to better understand the evolutionary relationships among species of particular conservation concern.
• Methods A large subsample of the 153 populations studied contributed to an initial survey of nrITS ribotypes. Smaller subsets were then sequenced for four plastid regions and the first intron of the low-copy nuclear gene LEAFY. Rooted using Steveniella as outgroup, phylogenetic trees were generated using parsimony and Bayesian methods from each of the three datasets, supplemented with a ribotype network.
• Key results The resulting trees collectively determined the order of branching of the early divergent taxa as H. comperianum > H. robertianum group > H. formosum, events that also involved significant morphological divergence. Relaxed molecular clock dating suggests that these divergences preceded the Pleistocene glaciations-the origin of the H. robertianum group may have coincided with the Messinian salinity crisis-and occurred in Asia Minor and/or the Caucasus. Among more controversial taxa of the H. hircinum-jankae clade, which are only subtly morphologically divergent, topological resolution is poorer and topological incongruence between datasets is consequently greater.
• Conclusions Plastid sequence divergence is broadly consistent with prior, morphologically circumscribed taxa and indicates a division between H. hircinum-adriaticum to the west of the Carpathians and H. jankae-caprinum (plus local endemics) to the east-a distinction also suggested by ITS ribotypes. LEAFY phylogenies are less congruent with prior taxonomic arrangements and include one likely example of paralogy. Himantoglossum metlescisianum fully merits its IUCN Endangered status. Potentially significant genetic variation was detected within Steveniella satyrioides, H. robertianum and H. hircinum. However, confident circumscription of the more derived species of Himantoglossum s.s., including local endemics of hybrid origin, must await future morphometric and population-genetic analyses.