Biology subjects

Harald Detering

Publications and source records attributed to Harald Detering.

3 recordsLinked to original sources

bioRxiv2016

Colonization and diversification of aquatic insects on three Macaronesian archipelagos using 59 nuclear loci derived from a draft genome

The study of processes driving diversification requires a fully sampled and well resolved phylogeny. Multilocus approaches to the study of recent diversification provide a powerful means to study the evolutionary process, but their application remains restricted because multiple unlinked loci with suitable variation for phylogenetic or coalescent analysis are not available for most non-model taxa. Here we identify novel, putative single-copy nuclear DNA (nDNA) phylogenetic markers to study the colonization and diversification of an aquatic insect species complex, Cloeon dipterum L. 1761 (Ephemeroptera: Baetidae), in Macaronesia. Whole-genome sequencing data from one member of the species complex were used to identify 59 nDNA loci (32,213 base pairs), followed by Sanger sequencing of 29 individuals sampled from 13 islands of three Macaronesian archipelagos. Multispecies coalescent analyses established six putative species. Three island species formed a monophyletic clade, with one species occurring on the Azores, Europe and North America. Ancestral state reconstruction indicated at least two colonization events from the mainland (Canaries, Azores) and one within the archipelago (between Madeira and the Canaries). Random subsets of the 59 loci showed a positive linear relationship between number of loci and node support. In contrast, node support in the multispecies coalescent tree was negatively correlated with mean number of phylogenetically informative sites per locus, suggesting a complex relationship between tree resolution and marker variability. Our approach highlights the value of combining coalescent-based phylogeography, species delimitation, and phylogenetic reconstruction to resolve recent diversification events in an archipelago species complex.

Evolutionary Biology↗

bioRxiv2016

High habitat-specificity in fungal communities of an oligo-mesotrophic, temperate lake

Freshwater fungi are a poorly studied paraphyletic group that include a high diversity of phyla. Most studies of aquatic fungal diversity have focussed on single habitats, thus the linkage between habitat heterogeneity and fungal diversity remains largely unexplored. We took 216 samples from 54 locations representing eight different habitats in meso-oligotrophic, temperate Lake Stechlin in northern Germany, including the pelagic and littoral water column, sediments, and biotic substrates. We pyrosequenced with an universal eukaryotic marker within the ribosomal large subunit (LSU) in order to compare fungal diversity, community structure, and species turnover among habitats. Our analysis recovered 1024 fungal OTUs (97% criterion). Diversity was highest in the sediment, biofilms, and benthic samples (293-428 OTUs), intermediate in water and reed samples (36-64 OTUs), and lowest in plankton (8 OTUs) samples. NMDS clustering clearly grouped the eight studied habitats into six clusters, indicating that total diversity was strongly influenced by turnover among habitats. Fungal communities exhibited pronounced changes at the levels of phylum and order along a gradient from littoral to pelagic habitats. The large majority of OTUs could not be classified below the order level due to the lack of aquatic fungal entries in taxonomic databases. Our study provides a first estimate of lake-wide fungal diversity and highlights the important contribution of habitat-specificity to total fungal diversity. This remarkable diversity is probably an underestimate, because most lakes undergo seasonal changes and previous studies have uncovered differences in fungal communities among lakes.

Ecology↗

bioRxiv2016

DiscoMark: Nuclear marker discovery from orthologous sequences using draft genome data

High-throughput sequencing has laid the foundation for fast and cost-effective development of phylogenetic markers. Here we present the program DO_SCPCAPISCOC_SCPCAPMO_SCPCAPARKC_SCPCAP, which streamlines the development of nuclear DNA (nDNA) markers from whole-genome (or whole-transcriptome) sequencing data, combining local alignment, alignment trimming, reference mapping and primer design based on multiple sequence alignments in order to design primer pairs from input orthologous sequences. In order to demonstrate the suitability of DO_SCPCAPISCOC_SCPCAPMO_SCPCAPARKC_SCPCAP we designed markers for two groups of species, one consisting of closely related species and one group of distantly related species. For the closely related members of the species complex of Cloeon dipterum s.l. (Insecta, Ephemeroptera), the program discovered a total of 78 markers. Among these, we selected eight markers for amplification and Sanger sequencing. The exon sequence alignments (2,526 base pairs (bp)) were used to reconstruct a well supported phylogeny and to infer clearly structured haplotype networks. For the distantly related species we designed primers for several families in the insect order Ephemeroptera, using available genomic data from four sequenced species. We developed primer pairs for 23 markers that are designed to amplify across several families. The DO_SCPCAPISCOC_SCPCAPMO_SCPCAPARKC_SCPCAP program will enhance the development of new nDNA markersby providing a streamlined, automated approach to perform genome-scale scans for phylogenetic markers. The program is written in Python, released under a public license (GNU GPL v2), and together with a manual and example data set available at: https://github.com/hdetering/discomark.

Bioinformatics↗