| 1. |
- Heingård, Miriam, et al.
(författare)
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FoxB, a new and highly conserved key factor in arthropod dorsal-ventral (DV) limb patterning
- 2019
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Ingår i: EvoDevo. - : BMC. - 2041-9139. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Forkhead box (Fox) transcription factors evolved early in animal evolution and represent important components of conserved gene regulatory networks (GRNs) during animal development. Most of the researches concerning Fox genes, however, are on vertebrates and only a relatively low number of studies investigate Fox gene function in invertebrates. In addition to this shortcoming, the focus of attention is often restricted to a few well-characterized Fox genes such as FoxA (forkhead), FoxC (crocodile) and FoxQ2. Although arthropods represent the largest and most diverse animal group, most other Fox genes have not been investigated in detail, not even in the arthropod model species Drosophila melanogaster. In a general gene expression pattern screen for panarthropod Fox genes including the red flour beetle Tribolium castaneum, the pill millipede Glomeris marginata, the common house spider Parasteatoda tepidariorum, and the velvet worm Euperipatoides kanangrensis, we identified a Fox gene with a highly conserved expression pattern along the ventral ectoderm of arthropod and onychophoran limbs. Functional investigation of FoxB in Parasteatoda reveals a hitherto unrecognized important function of FoxB upstream of wingless (wg) and decapentaplegic (dpp) in the GRN orchestrating dorsal-ventral limb patterning.
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| 2. |
- Janssen, Ralf, 1975-, et al.
(författare)
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A chelicerate Wnt gene expression atlas : novel insights into the complexity of arthropod Wnt-patterning
- 2021
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Ingår i: EvoDevo. - : BioMed Central (BMC). - 2041-9139. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The Wnt genes represent a large family of secreted glycoprotein ligands that date back to early animal evolution. Multiple duplication events generated a set of 13 Wnt families of which 12 are preserved in protostomes. Embryonic Wnt expression patterns (Wnt-patterning) are complex, representing the plentitude of functions these genes play during development. Here, we comprehensively investigated the embryonic expression patterns of Wnt genes from three species of spiders covering both main groups of true spiders, Haplogynae and Entelegynae, a mygalomorph species (tarantula), as well as a distantly related chelicerate outgroup species, the harvestman Phalangium opilio. All spiders possess the same ten classes of Wnt genes, but retained partially different sets of duplicated Wnt genes after whole genome duplication, some of which representing impressive examples of sub- and neo-functionalization. The harvestman, however, possesses a more complete set of 11 Wnt genes but with no duplicates. Our comprehensive data-analysis suggests a high degree of complexity and evolutionary flexibility of Wnt-patterning likely providing a firm network of mutational protection. We discuss the new data on Wnt gene expression in terms of their potential function in segmentation, posterior elongation, and appendage development and critically review previous research on these topics. We conclude that earlier research may have suffered from the absence of comprehensive gene expression data leading to partial misconceptions about the roles of Wnt genes in development and evolution.
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| 3. |
- Janssen, Ralf, 1975-, et al.
(författare)
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Lack of evidence for conserved parasegmental grooves in arthropods
- 2022
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Ingår i: Development, Genes and Evolution. - : Springer. - 0949-944X .- 1432-041X. ; 232:1, s. 27-37
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Tidskriftsartikel (refereegranskat)abstract
- In the arthropod model species Drosophila melanogaster, a dipteran fly, segmentation of the anterior-posterior body axis is under control of a hierarchic gene cascade. Segmental boundaries that form morphological grooves are established posteriorly within the segmental expression domain of the segment-polarity gene (SPG) engrailed (en). More important for the development of the fly, however, are the parasegmental boundaries that are established at the interface of en expressing cells and anteriorly adjacent wingless (wg) expressing cells. In Drosophila, both segmental and transient parasegmental grooves form. The latter are positioned anterior to the expression of en. Although the function of the SPGs in establishing and maintaining segmental and parasegmental boundaries is highly conserved among arthropods, parasegmental grooves have only been reported for Drosophila, and a spider (Cupiennius salei). Here, we present new data on en expression, and re-evaluate published data, from four distantly related spiders, including Cupiennius, and a distantly related chelicerate, the harvestman Phalangium opilio. Gene expression analysis of en genes in these animals does not corroborate the presence of parasegmental grooves. Consequently, our data question the general presence of parasegmental grooves in arthropods.
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| 4. |
- Janssen, Ralf, 1975-, et al.
(författare)
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The evolution and expression of panarthropod frizzled genes
- 2015
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Wnt signaling regulates many important processes during metazoan development. It has been shown that Wnt ligands represent an ancient diverse family of proteins that likely function in complex signaling landscapes to induce target cells and tissues via receptors including those of the Frizzled family. The four subfamilies of Fz receptors also evolved early in metazoan evolution. To compare with other metazoans and arthropods such as insects, we explored the repertoire of fz genes in three panarthropod species: Parasteatoda tepidariorum, Glomeris marginata and Euperipatoides kanangensis, representing the Chelicerata, Myriapoda and Onychophora respectively. We found that these three diverse panarthropods each have four fz genes with representatives of all four metazoan fz subfamilies found in Glomeris and Euperipatoides while Parasteatoda does not have a fz3 gene but has two fz4 paralogues. Furthermore we characterized the expression patterns of all fz genes in Parasteatoda, Glomeris and Euperipatoides and found both conserved and divergent expression of these genes among these animals and in comparison to insects. Our study provides new insights into the evolution and developmental functions of fz receptors and Wnt signaling more generally.
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| 5. |
- Schwager, Evelyn E., et al.
(författare)
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The house spider genome reveals an ancient whole-genome duplication during arachnid evolution
- 2017
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Ingår i: BMC Biology. - : BIOMED CENTRAL LTD. - 1741-7007. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: The duplication of genes can occur through various mechanisms and is thought to make a major contribution to the evolutionary diversification of organisms. There is increasing evidence for a large-scale duplication of genes in some chelicerate lineages including two rounds of whole genome duplication (WGD) in horseshoe crabs. To investigate this further, we sequenced and analyzed the genome of the common house spider Parasteatoda tepidariorum.Results: We found pervasive duplication of both coding and non-coding genes in this spider, including two clusters of Hox genes. Analysis of synteny conservation across the P. tepidariorum genome suggests that there has been an ancient WGD in spiders. Comparison with the genomes of other chelicerates, including that of the newly sequenced bark scorpion Centruroides sculpturatus, suggests that this event occurred in the common ancestor of spiders and scorpions, and is probably independent of the WGDs in horseshoe crabs. Furthermore, characterization of the sequence and expression of the Hox paralogs in P. tepidariorum suggests that many have been subject to neo-functionalization and/or sub-functionalization since their duplication.Conclusions: Our results reveal that spiders and scorpions are likely the descendants of a polyploid ancestor that lived more than 450 MYA. Given the extensive morphological diversity and ecological adaptations found among these animals, rivaling those of vertebrates, our study of the ancient WGD event in Arachnopulmonata provides a new comparative platform to explore common and divergent evolutionary outcomes of polyploidization events across eukaryotes.
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| 6. |
- Turetzek, Natascha, et al.
(författare)
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Hox genes in spiders : Their significance for development and evolution
- 2024
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Ingår i: Seminars in Cell and Developmental Biology. - : Elsevier. - 1084-9521 .- 1096-3634. ; 152-153, s. 24-34
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Forskningsöversikt (refereegranskat)abstract
- Hox genes are known for their role in the specification of typical body plan features in animals. Evolutionary changes in Hox gene function are believed to be involved in the emergence of the diverse body plans we observe in animals today. Spiders share many body plan features with other arthropods, but also have numerous unique traits of their own. Studies of spider Hox genes have already provided insights into evolutionarily conserved and derived features of the spider body plan and their genetic basis. However, many aspects of Hox gene biology have been insufficiently studied in spiders so far. In this review, we highlight previous comparative studies of Hox genes in spiders and their significance for our understanding of the evolution of the spider body plan. We also identify aspects of Hox gene biology that need to be studied in greater detail. Many spider Hox genes have not been investigated beyond their mRNA expression patterns, and the role of Hox genes with apparently plesiomorphic or dual functions, like ftz and Hox3 is still unclear. Spiders have a duplicated Hox gene cluster, but possible sub-or neofunctionalisation of duplicates have not yet been studied systematically. Future research should therefore focus on these issues, in addition to the role of Polycomb and trithorax-mediated regulation, the identification of regulatory regions, cofactors or spider-specific target genes, and the significance of non-coding RNAs transcribed from within the Hox cluster and even from the antisense strand of particular Hox genes.
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