bioRxiv Science⌕ Search

bioRxiv · 10.1101/575308

A validated workflow for rapid taxonomic assignment and monitoring of a national fauna of bees (Apiformes) using high throughput barcoding

Abstract

Improved taxonomic methods are needed to quantify declining populations of insect pollinators. This study devises a high-throughput DNA barcoding protocol for a regional fauna (United Kingdom) of bees (Apiformes), consisting of reference library construction, a proof-of-concept monitoring scheme, and the deep barcoding of individuals to assess potential artefacts and organismal associations. A reference database of Cytochrome Oxidase subunit 1 (cox1) sequences including 92.4% of 278 bee species known from the UK showed high congruence with morphological taxon concepts, but molecular species delimitations resulted in numerous split and (fewer) lumped entities within the Linnaean species. Double tagging permitted deep illumina sequencing of 762 separate individuals of bees from a UK-wide survey. Extracting the target barcode from the amplicon mix required a new protocol employing read abundance and phylogenetic position, which revealed 180 molecular entities of Apiformes identifiable to species. An additional 72 entities were ascribed to mitochondrial pseudogenes based on patterns of read abundance and phylogenetic relatedness to the reference set. Clustering of reads revealed a range of secondary Operational Taxonomic Units (OTUs) in almost all samples, resulting from traces of insect species caught in the same traps, organisms associated with the insects including a known mite parasite of bees, and the common detection of human DNA, besides evidence for low-level cross-contamination in pan traps and laboratory steps. Custom scripts were generated to conduct critical steps of the bioinformatics protocol. The resources built here will greatly aid DNA-based monitoring to inform management and conservation policies for the protection of pollinators.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Creedy, T. J., Norman, H., Tang, C. Q., Chin, K. Q., Andujar, C., Arribas, P., O'Connor, R., Carvell, C., Notton, D. G., Vogler, A. P.. 2019-03-13. A validated workflow for rapid taxonomic assignment and monitoring of a national fauna of bees (Apiformes) using high throughput barcoding. https://doi.org/10.1101/575308

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

T cell transcriptomes in simulated microgravity in vivo

Spaceflight exposes astronauts to a combination of stressors, among which microgravity remains the least well characterized at the level of human immune cell function. We examined the in vivo effect of long-term simulated microgravity (SMG) on T cell transcriptomes in ten healthy male volunteers who completed a three-week dry immersion protocol without countermeasures. Peripheral blood was collected at five time points covering a pre-immersion baseline (day -7), three intra-exposure time points (days 7, 14 and 21) and a recovery time point one week after the end of exposure (day 28). CD3+ T cells were isolated and analysed by RNA-seq, with differential expression assessed per volunteer and KEGG pathway enrichment used to identify the most affected gene networks. SMG was associated with transcript-level changes in genes mapping to key molecular pathways, including those involved in cell proliferation, cell-cycle regulation, maintenance of genome integrity, and oncogenic and tumour-suppressor networks. Hub genes shared across the most significant pathways were differentially expressed in the majority of volunteers. A notable finding was pronounced inter-individual heterogeneity: samples clustered primarily by volunteer identity, yet a coordinated temporal shift during exposure and a partial return toward baseline by day 28 were detectable across donors, and these changes occurred in the absence of detectable systemic inflammation. These results indicate that SMG is associated with altered T cell transcriptional programs in vivo and that the response is sufficiently variable between individuals to favor personalized rather than uniform countermeasure strategies.

molecular biology↗

Physiological mapping and prediction reveal stress-responsive translation initiation landscapes

Translation initiation defines the protein output of the transcriptome, but its physiological dynamics in cells and tissues remain incompletely characterized. Here we develop TISCA2, an inhibitor-free method that captures eIF5B-associated initiating ribosomes to map translation initiation sites genome-wide. By directly identifying start sites rather than inferring translation from elongating-ribosome periodicity, TISCA2 improves the detection of short and overlapping translons. Translation of a subset of TISCA2-identified translons is supported by N-terminal proteomics and HLA-I immunopeptidomics. The arsenite-induced integrated stress response broadly redistributes start-site usage, reducing upstream initiation in favor of downstream initiation. TISCA2 further reveals tissue-specific initiation landscapes in vivo, with increased detection of downstream candidate start sites in the testis. Finally, we develop IncepTIS, a sequence-based deep learning model that predicts position-resolved and condition-dependent initiation landscapes. IncepTIS-guided optimization generates de novo mRNA 5' leaders with stress-responsive initiation patterns. Together, TISCA2 and IncepTIS provide an experimental and computational framework for mapping, predicting and engineering translation initiation in mammalian cells and tissues.

molecular biology↗

Optimal compositions of potent sliced-siRNA with DNA bases substitution and insights of Ago2 slicing actions

We have previously characterized the nucleotide compositions of single-stranded ago2-sliced small interfering RNAs (sliced-siRNA, sliRNA), a novel type of potent RNAi trigger designed based on the biogenesis mechanism of miRNA-451. sliRNAs have on par antisense mediated silencing activity but about 1000-fold reduced passenger strand activity compared to siRNA. In the current study, to further characterize sliRNAs to facilitate their in vivo application, we have investigated the effects of substituting RNA nucleotides (nts) in sliRNA with DNA nts (sliDRNAs), which will allow us to study the potential effects on their processing, maturation, and silencing activity from individual or multiple nts at different positions. Our results showed sliDRNAs have distinguished composition from siRNA with DNA nts (siDRNA), indicated that, in addition to their different biogenesis mechanisms, these two types of RNAi triggers may also have adopted additional different silencing mechanisms. Our results also revealed some mechanism related to how Ago2 executes its slicer activity and the effects on sliRNA potency by trimming and tailing during sliRNA maturation. These results have paved the way for using other chemically modified nts in sliRNAs that may enhance their in vivo stability and transportability to facilitate their in vivo applications.

molecular biology↗