Restriction-site associated DNA sequencing supports a sister group relationship of Nigritella and Gymnadenia (Orchidaceae)

Publication date: Available online 23 March 2019Source: Molecular Phylogenetics and EvolutionAuthor(s): Marie K. Brandrud, Ovidiu Paun, Richard Lorenz, Juliane Baar, Mikael HedrénAbstractThe orchid genus Nigritella is closely related to Gymnadenia and has from time to time been merged with the latter. Although Nigritella is morphologically distinct, it has been suggested that the separating characters are easily modifiable and subject to rapid evolutionary change. So far, molecular phylogenetic studies have either given support for the inclusion of Nigritella in Gymnadenia, or for their separation as different genera. To resolve this issue, we analysed data obtained from Restriction-site associated DNA sequencing, RADseq, which provides a large number of SNPs distributed across the entire genome. To analyse samples of different ploidies, we take an analytical approach of building a reduced genomic reference based on de novo RADseq loci reconstructed from diploid accessions only, which we further use to map and call variants across both diploid and polyploid accessions. We found that Nigritella is distinct from Gymnadenia forming a well-supported separate clade, and that genetic diversity within Gymnadenia is high. Within Gymnadenia, taxa characterized by an ITS-E ribotype (G. conopsea s.str. (early flowering) and G. odoratissima), are divergent from taxa characterized by ITS-L ribotype (G. frivaldii, G. densiflora and late flowering G. conopsea). Gymnigritella runei is confi...
Source: Molecular Phylogenetics and Evolution - Category: Molecular Biology Source Type: research