Asselman, P. | bioRxiv Science

bioRxiv2023

Truly the best of both worlds: merging lineage-specific and universal baiting kits to maximize phylogenomic inference

PREMISEThe development of RNA baiting kits for reduced representation approaches of genomic sequencing is popularized, with universal and clade-specific kits for flowering plants available. Here, we provided an updated version of the Annonaceae bait kit targeting 799 low copy genes, known as Annonaceae799. METHODSThis new version of the kit combines the original 469 genes from the previous version of the Annonaceae kit with 334 genes from the universal Angiosperms353 kit. We also compared the results obtained using the Original Angiosperms353 kit with our custom approach. Parsimony informative sites (pis) were evaluated for all genes and combined matrices. RESULTSThe new version of the kit has extremely high rates of gene recovery. On average, 796 genes were recovered per sample, and 777.5 genes recovered with at least 50% of their size. Off-target reads were also obtained. Evaluating size, the proportion of on- and off-target regions, and the number of pis, the genes from the Angiosperms353 usually outperform the genes from the original Annonaceae bait kit. DISCUSSIONThe results obtained show that the new sequences from the Angiosperms353 aggregate variable and putative relevant bases for future studies on species-level phylogenomics, and within species studies. The merging of kits also creates a link between projects and makes available new genes for phylogenetic and populational studies.

evolutionary biology↗

bioRxiv2021

Plastid phylogenomics of the Sansevieria clade (Dracaena; Asparagaceae) resolves a rapid evolutionary radiation

Sansevierias are a diverse group of flowering plants native to Africa, Madagascar, the Arabian Peninsula and the Indian subcontinent, popular outside their native range as low maintenance houseplants. Traditionally recognized as a distinct genus, Sansevieria was recently merged with the larger genus Dracaena based on molecular phylogenetic data. Within the Sansevieria clade, taxonomic uncertainties remain despite numerous attempts to classify the species. We aim to arrive at a robust phylogeny using a plastid phylogenomic approach, and estimate a time-frame of diversification to infer the evolutionary history of the group, including geographical and morphological evolution. Molecular data was obtained using genome skimming for 50 Sansevieria, representing all informal groups previously instated based on morphology, and two Dracaena sensu stricto species. The resulting Maximum Likelihood phylogenetic hypotheses are generally well supported, except for some very short branches along the backbone of the tree. The time-calibrated phylogeny indicates a recent rapid radiation with the main clades emerging in the Pliocene. Two well-supported clades align with previously defined informal groups, i.e., Sansevieria section Dracomima, characterised by the Dracomima-type inflorescence, and the Zeylanica group, native to the Indian subcontinent. Other morphologically defined informal groups are shown to be polyphyletic: a pattern due to convergent evolution of the identifying characters. Cylindrical leaves arose multiple times independently in the evolution of the Sansevieria clade and similarly, the Cephalantha-type inflorescence has originated multiple times from an ancestor with a Sansevieria-type inflorescence. To provide a more accessible tool for species identification and delimitation, genes and spacer regions were screened for variability and phylogenetic informativeness to investigate their potential as chloroplast DNA barcodes. Candidate chloroplast DNA barcodes include the trnH-rpl12, ndhH-rps15, psbE-petL, psbT-psbN, rps18-rpl20 intergenic spacers, the chloroplast gene rps8 and the first intron of ycf3.

evolutionary biology↗