The i5K Initiative: Advancing Arthropod Genomics for Knowledge, Human Health, Agriculture, and the Environment

Insects and their arthropod relatives including mites, spiders, and crustaceans play major roles in the world’s terrestrial, aquatic, and marine ecosystems. Arthropods compete with humans for food and transmit devastating diseases. They also comprise the most diverse and successful branch of metazoan evolution, with millions of extant species. Here, we describe an international effort to guide arthropod genomic efforts, from species prioritization to methodology and informatics. The 5000 arthropod genomes initiative (i5K) community met formally in 2012 to discuss a roadmap for sequencing and analyzing 5000 high-priority arthropods and is continuing this effort via pilot projects, the development of standard operating procedures, and training of students and career scientists. With university, governmental, and industry support, the i5K Consortium aspires to deliver sequences and analytical tools for each of the arthropod branches and each of the species having beneficial and negative effects on humankind

Metagenome skimming of insect specimen pools: potential for comparative genomics

Metagenomic analyses are challenging in metazoans, but high-copy number and repeat regions can be assembled from lowcoverage sequencing by “genome skimming,” which is applied here as a new way of characterizing metagenomes obtained in an ecological or taxonomic context. Illumina shotgun sequencing on two pools of Coleoptera (beetles) of approximately 200 species each were assembled into tens of thousands of scaffolds. Repeated low-coverage sequencing recovered similar scaffold sets consistently, although approximately 70% of scaffolds could not be identified against existing genome databases. Identifiable scaffolds included mitochondrial DNA, conserved sequences with hits to expressed sequence tag and protein databases, and knownrepeatelementsof high and low complexity, includingnumerous copies ofrRNAandhistone genes.Assemblies of histones captured a diversity of gene order and primary sequence in Coleoptera. Scaffolds with similarity to multiple sites in available coleopteran genome sequences for Dendroctonus and Tribolium revealed high specificity of scaffolds to either of these genomes, in particular for high-copy number repeats. Numerous “clusters” of scaffolds mapped to the same genomic site revealed intraand/or intergenomic variation within a metagenome pool. In addition to effect of taxonomic composition of the metagenomes, the number of mapped scaffolds also revealed structural differences between the two reference genomes, although the significance of this striking finding remains unclear. Finally, apparently exogenous sequences were recovered, including potential food plants, fungal pathogens, and bacterial symbionts. The “metagenome skimming” approach is useful for capturing the genomic diversity of poorly studied, species-rich lineages and opens new prospects in environmental genomic

Targeted sequencing for high-resolution evolutionary analyses following genome duplication in salmonid fish:Proof of concept for key components of the insulin-like growth factor axis

Acknowledgements This study was funded by a Natural Environment Research Council grant (NERC, project code: NBAF704). FML is funded by a NERC Doctoral Training Grant (Project Reference: NE/L50175X/1). RLS was an undergraduate student at the University of Aberdeen and benefitted from financial support from the School of Biological Sciences. DJM is indebted to Dr. Steven Weiss (University of Graz, Austria), Dr. Takashi Yada (National Research Institute of Fisheries Science, Japan), Dr. Robert Devlin (Fisheries and Oceans Canada, Canada), Prof. Samuel Martin (University of Aberdeen, UK), Mr. Neil Lincoln (Environment Agency, UK) and Prof. Colin Adams/Mr. Stuart Wilson (University of Glasgow, UK) for providing salmonid material or assisting with its sampling. We are grateful to staff at the Centre for Genomics Research (University of Liverpool, UK) (i.e. NERC Biomolecular Analysis Facility – Liverpool; NBAF-Liverpool) for performing sequence capture/Illumina sequencing and providing us with details on associated methods that were incorporated into the manuscript. Finally, we are grateful to the organizers of the Society of Experimental Biology Satellite meeting 'Genome-powered perspectives in integrative physiology and evolutionary biology' (held in Prague, July 2015) for inviting us to contribute to this special edition of Marine Genomics and hosting a really stimulating meeting.Peer reviewedPublisher PD

Hybrid capture data unravel a rapid radiation of pimpliform parasitoid wasps (Hymenoptera: Ichneumonidae: Pimpliformes)

The parasitoid wasp family Ichneumonidae is among the most diverse groups of organisms, with conservative estimates suggesting that it contains more species than all vertebrates together. However, ichneumonids are also among the most severely understudied groups, and our understanding of their evolution is hampered by the lack of a robust higher‐level phylogeny of this group. Based on newly generated transcriptome sequence data, which were filtered according to several criteria of phylogenetic informativeness, we developed target DNA enrichment baits to capture 93 genes across species of Ichneumonidae. The baits were applied to DNA of 55 ichneumonids, with a focus on Pimpliformes, an informal group containing nine subfamilies. Phylogenetic trees were inferred under maximum likelihood and Bayesian approaches, at both the nucleotide and amino acid levels. We found maximum support for the monophyly of Pimpliformes but low resolution and very short branches close to its base, strongly suggesting a rapid radiation. Two genera and one genus‐group were consistently recovered in unexpected parts of the tree, prompting changes in their higher‐level classification: Pseudorhyssa Merrill, currently classified in the subfamily Poemeniinae, is transferred to the tribe Delomeristini within Pimplinae, and Hemiphanes Förster is moved from Orthocentrinae to Cryptinae. Likewise, the tribe Theroniini is resurrected for the Theronia group of genera (stat. rev.). Phylogenetic analyses, in which we gradually increased the numbers of genes, revealed that the initially steep increase in mean clade support slows down at around 40 genes, and consideration of up to 93 genes still left various nodes in the inferred phylogenetic tree poorly resolved. It remains to be shown whether more extensive gene or taxon sampling can resolve the early evolution of the pimpliform subfamilies.This is the pre-peer reviewed version of the following article: Klopfstein, S., Langille, B., Spasojevic, T., Broad, G.R., Cooper, S.J.B., Austin, A.D. and Niehuis, O. (2019), Hybrid capture data unravel a rapid radiation of pimpliform parasitoid wasps (Hymenoptera: Ichneumonidae: Pimpliformes). Syst Entomol, 44: 361-383. , which has been published in final form at doi:10.1111/syen.12333. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving The attached document is the authors’ submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it

Population genomics of marine zooplankton

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Bucklin, Ann et al. "Population Genomics of Marine Zooplankton." Population Genomics: Marine Organisms. Ed. Om P. Rajora and Marjorie Oleksiak. Springer, 2018. doi:10.1007/13836_2017_9.The exceptionally large population size and cosmopolitan biogeographic distribution that distinguish many – but not all – marine zooplankton species generate similarly exceptional patterns of population genetic and genomic diversity and structure. The phylogenetic diversity of zooplankton has slowed the application of population genomic approaches, due to lack of genomic resources for closelyrelated species and diversity of genomic architecture, including highly-replicated genomes of many crustaceans. Use of numerous genomic markers, especially single nucleotide polymorphisms (SNPs), is transforming our ability to analyze population genetics and connectivity of marine zooplankton, and providing new understanding and different answers than earlier analyses, which typically used mitochondrial DNA and microsatellite markers. Population genomic approaches have confirmed that, despite high dispersal potential, many zooplankton species exhibit genetic structuring among geographic populations, especially at large ocean-basin scales, and have revealed patterns and pathways of population connectivity that do not always track ocean circulation. Genomic and transcriptomic resources are critically needed to allow further examination of micro-evolution and local adaptation, including identification of genes that show evidence of selection. These new tools will also enable further examination of the significance of small-scale genetic heterogeneity of marine zooplankton, to discriminate genetic “noise” in large and patchy populations from local adaptation to environmental conditions and change.Support was provided by the US National Science Foundation to AB and RJO (PLR-1044982) and to RJO (MCB-1613856); support to IS and MC was provided by Nord University (Norway)