Comparing newly obtained and previously known nucleotide and amino-acid sequences underpins modern biological research. BLAST is a well-established tool for such comparisons but is challenging to use on new data sets. We combined a user-centric design philosophy with sustainable software development approaches to create Sequenceserver, a tool for running BLAST and visually inspecting BLAST results for biological interpretation. Sequenceserver uses simple algorithms to prevent potential analysis errors and provides flexible text-based and visual outputs to support researcher productivity. Our software can be rapidly installed for use by individuals or on shared servers.
A phylogenetic tree at the species level is still far off for highly diverse insect orders, including the Coleoptera, but the taxonomic breadth of public sequence databases is growing. In addition, new types of data may contribute to increasing taxon coverage, such as metagenomic shotgun 2 sequencing for assembly of mitogenomes from bulk specimen samples. The current study explores the application of these techniques for large-scale efforts to build the tree of Coleoptera. We used shotgun data from 17 different ecological and taxonomic datasets (5 unpublished) to assemble a total of 1942 mitogenome contigs of >3000 bp. These sequences were combined into a single dataset together with all mitochondrial data available at GenBank, in addition to nuclear markers widely used in molecular phylogenetics. The resulting matrix of nearly 16000 species with two or more loci produced trees (RAxML) showing overall congruence with the Linnaean taxonomy at hierarchical levels from suborders to genera. We tested the role of full-length mitogenomes in stabilizing the tree from GenBank data, as mitogenomes might link terminals with non-overlapping gene representation. However, the mitogenome data were only partly useful in this respect, presumably because of the purely automated approach to assembly and gene delimitation, but improvements in future may be possible by using multiple assemblers and manual curation. In conclusion, the combination of data mining and metagenomic sequencing of bulk samples provided the largest phylogenetic tree of Coleoptera to date, which represents a summary of existing phylogenetic knowledge and a defensible tree of great utility, in particular for studies at the intra-familial level, despite some shortcomings for resolving basal nodes.
A phylogenetic tree at the species level is still far off for highly diverse insect orders, including the Coleoptera, but the taxonomic breadth of public sequence databases is growing. In addition, new types of data may contribute to increasing taxon coverage, such as metagenomic shotgun sequencing for assembly of mitogenomes from bulk specimen samples. The current study explores the application of these techniques for large-scale efforts to build the tree of Coleoptera. We used shotgun data from 17 different ecological and taxonomic datasets (5 unpublished) to assemble a total of 1942 mitogenome contigs of >3000 bp. These sequences were combined into a single dataset together with all mitochondrial data available at GenBank, in addition to nuclear markers widely used in molecular phylogenetics. The resulting matrix of nearly 16,000 species with two or more loci produced trees (RAxML) showing overall congruence with the Linnaean taxonomy at hierarchical levels from suborders to genera. We tested the role of full-length mitogenomes in stabilizing the tree from GenBank data, as mitogenomes might link terminals with non-overlapping gene representation. However, the mitogenome data were only partly useful in this respect, presumably because of the purely automated approach to assembly and gene delimitation, but improvements in future may be possible by using multiple assemblers and manual curation. In conclusion, the combination of data mining and metagenomic sequencing of bulk samples provided the largest phylogenetic tree of Coleoptera to date, which represents a summary of existing phylogenetic knowledge and a defensible tree of great utility, in particular for studies at the intra-familial level, despite some shortcomings for resolving basal nodes.
The >15 000 ant species are all highly social and show great variation in colony organization, complexity and behavior. The mechanisms by which such sociality evolved, as well as those underpinning the elaboration of ant societies since their $140 million year old common ancestor, have long been pondered. Here, we review recent insights generated using various genomic approaches. This includes understanding the molecular mechanisms underlying caste differentiation and the diversity of social structures, studying the impact of eusociality on genomic evolutionary rates, and investigating gene expression changes associated with differences in lifespan between castes. Furthermore, functional studies involving RNAi and CRISPR have recently been successfully applied to ants, opening the door to exciting research that promises to revolutionize the understanding of the evolution and diversification of social living.
The evolution of eusociality requires that individuals forgo some or all their own reproduction to assist the reproduction of others in their group, such as a primary egg-laying queen. A major open question is how genes and genetic pathways sculpt the evolution of eusociality, especially in rudimentary forms of sociality – those with smaller cooperative nests as compared with species such as honeybees that possess large societies. We lack comprehensive comparative studies examining shared patterns and processes across multiple social lineages. Here we examine the mechanisms of molecular convergence across two lineages of bees and wasps exhibiting such rudimentary societies. These societies consist of few individuals and their life histories range from facultative to obligately social. Using six species across four independent origins of sociality, we conduct a comparative meta-analysis of publicly available transcriptomes. Standard methods detected little similarity in patterns of differential gene expression in brain transcriptomes among reproductive and non-reproductive individuals across species. By contrast, both supervised machine learning and consensus co-expression network approaches uncovered sets of genes with conserved expression patterns among reproductive and non-reproductive phenotypes across species. These sets overlap substantially, and may comprise a shared genetic “toolkit” for sociality across the distantly related taxa of bees and wasps and independently evolved lineages of sociality. We also found many lineage-specific genes and co-expression modules associated with social phenotypes and possible signatures of shared life-history traits. These results reveal how taxon-specific molecular mechanisms complement a core toolkit of molecular processes in sculpting traits related to the evolution of eusociality.
A rectal valve is known from Bostrichiformia (e.g. Dermestidae, Bostrichidae, Ptinidae), Cucujiformia (e.g. Chrysmeloidea, Cleridae, Curculionoidea, Endomychidae, Tenebrionidae) and Buprestidae, associated with the cryptonephridial system for water recovery from fecal matter. The valve is probably homologous in at least the Bostrichiformia and Cucujiformia although the form it takes may not be. It comprises a sclerotized band lying in the wall of the rectum where this meets the perinephric membrane. The valve is plesiomorphically a narrow crimped ring, probably acting as a sphincter to retain fecal matter for water extraction. Apomorphically it extends longitudinally along the rectum and supports the perinephric chamber; this state has probably arisen independently several times. Larval and adult morphology may be similar or different. Within the Curculionoidea different apomorphic forms suggest monophyly of groups within the Anthribidae and Dryophthoridae, and within the curculionid subfamilies Entiminae, Mesoptiliinae, Molytinae and Cossoninae + Scolytinae, although limited weight should be placed on a single character. No support is provided for a relationship between the Platypodinae and Scolytinae. The genera Cylindrotypetes Zimmerman 1942 and Edaphotrypetes Morimoto 1995 are transferred from Molytinae: Phoenicobatini to Cossoninae: Pentrarthini.
Major evolutionary transitions describe how biological complexity arises; e.g. in the evolution of complex multicellular bodies, and superorganismal insect societies. Such transitions involve the evolution of division of labour, e.g. as queen and worker castes in insect societies. A key mechanistic hypothesis for the evolution of division of labour is that a shared set of genes co-opted from a common solitary ancestral ground plan - a so-called genetic toolkit for sociality - regulate insect castes across different levels of social complexity. The vespid wasps represent an excellent system in which to test this. Here, using conventional and machine learning analyses of brain transcriptome data from nine species of vespid wasps, we find evidence of a shared genetic toolkit across species representing different levels of social complexity, with a large suite of genes classifying castes correctly across species. However, we also found evidence of additional fine-scale differences in predictive gene sets, functional enrichment and rates of gene evolution that were related to level of social complexity, but also life-history traits (e.g. mode of colony founding). Thus, there appear to be shifts in the gene networks regulating social behaviour and rates of gene evolution that are influenced by innovations in both social complexity and life-history. These results suggest that the concept of a shared genetic toolkit for sociality may be too simplistic to fully describe the process of the major transition to sociality, even within a single lineage. Diversity in lineage, social complexity and life-history traits must be taken into account in the quest to uncover the molecular bases of the major transition to sociality.
Ant colonies ancestrally contained one queen and her non-reproductive workers. This is also the case for many but not all colonies of the Mediterranean big-headed ant Pheidole pallidula. Indeed, this species also has a derived form of social organization with multiple reproductive queens in the colony. The co-existence of two social forms also independently evolved in three other lineages of ants. In each of those lineages, variants of a supergene region of suppressed recombination determine social form. This is likely because supergene regions can link advantageous combinations of alleles from multiple loci. We thus hypothesized that a supergene region also determines colony queen number in the big-headed ant. To test this, we performed extensive population genetic analyses and genomic comparisons. We find no evidence of a supergene-like region with differentiation between single- and multiple-queen colonies. Our results show that a complex social polymorphism can evolve and be maintained without supergenes.
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