Ralf Janssen

Summary

Affiliation: Uppsala University
Country: Sweden

Publications

  1. pmc Conservation, loss, and redeployment of Wnt ligands in protostomes: implications for understanding the evolution of segment formation
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Villavägen 16, SE 75236 Uppsala, Sweden
    BMC Evol Biol 10:374. 2010
  2. doi request reprint Identification and embryonic expression of Wnt2, Wnt4, Wnt5 and Wnt9 in the millipede Glomeris marginata (Myriapoda: Diplopoda)
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden Electronic address
    Gene Expr Patterns 14:55-61. 2014
  3. doi request reprint Deciphering the onychophoran 'segmentation gene cascade': Gene expression reveals limited involvement of pair rule gene orthologs in segmentation, but a highly conserved segment polarity gene network
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden Electronic address
    Dev Biol 382:224-34. 2013
  4. doi request reprint Developmental abnormalities in Glomeris marginata (Villers 1789) (Myriapoda: Diplopoda): implications for body axis determination in a myriapod
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden
    Naturwissenschaften 100:33-43. 2013
  5. ncbi request reprint Diplosegmentation in the pill millipede Glomeris marginata is the result of dorsal fusion
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden
    Evol Dev 13:477-87. 2011
  6. pmc Expression of pair rule gene orthologs in the blastoderm of a myriapod: evidence for pair rule-like mechanisms?
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36, Uppsala, Sweden
    BMC Dev Biol 12:15. 2012
  7. doi request reprint Segment polarity gene expression in a myriapod reveals conserved and diverged aspects of early head patterning in arthropods
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden
    Dev Genes Evol 222:299-309. 2012
  8. doi request reprint Gene expression patterns in an onychophoran reveal that regionalization predates limb segmentation in pan-arthropods
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36 Uppsala, Sweden
    Evol Dev 12:363-72. 2010
  9. doi request reprint An abnormally developed embryo of the pill millipede Glomeris marginata that lacks dorsal segmental derivatives
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
    Dev Genes Evol 221:351-5. 2011
  10. doi request reprint Evidence for Wg-independent tergite boundary formation in the millipede Glomeris marginata
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala, Sweden
    Dev Genes Evol 218:361-70. 2008

Detail Information

Publications18

  1. pmc Conservation, loss, and redeployment of Wnt ligands in protostomes: implications for understanding the evolution of segment formation
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Villavägen 16, SE 75236 Uppsala, Sweden
    BMC Evol Biol 10:374. 2010
    ..We also characterised Wnt gene expression in the latter three species, and further investigated expression of these genes in the beetle Tribolium castaneum...
  2. doi request reprint Identification and embryonic expression of Wnt2, Wnt4, Wnt5 and Wnt9 in the millipede Glomeris marginata (Myriapoda: Diplopoda)
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden Electronic address
    Gene Expr Patterns 14:55-61. 2014
    ..Prominent expression of Wnt4 in dorsal tissue implies a role in dorsal segmentation and suggests that Wnt4 may be the predicted substitute for the previously reported missing expression of wg/Wnt1 in dorsal tissue. ..
  3. doi request reprint Deciphering the onychophoran 'segmentation gene cascade': Gene expression reveals limited involvement of pair rule gene orthologs in segmentation, but a highly conserved segment polarity gene network
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden Electronic address
    Dev Biol 382:224-34. 2013
    ..This may suggest that the common ancestor of lophotrochozoans and ecdysozoans was already segmented utilising the same SPG-network, or that the SPG-network was recruited independently in annelids and onychophorans/arthropods...
  4. doi request reprint Developmental abnormalities in Glomeris marginata (Villers 1789) (Myriapoda: Diplopoda): implications for body axis determination in a myriapod
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden
    Naturwissenschaften 100:33-43. 2013
    ..It is proposed that the formation of D. posterior-type embryos could be caused by the formation of two instead of only one posterior cumulus early during development...
  5. ncbi request reprint Diplosegmentation in the pill millipede Glomeris marginata is the result of dorsal fusion
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden
    Evol Dev 13:477-87. 2011
    ..If the former is the case, my work may provide an impressive example of Haeckel's recapitulation theory...
  6. pmc Expression of pair rule gene orthologs in the blastoderm of a myriapod: evidence for pair rule-like mechanisms?
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36, Uppsala, Sweden
    BMC Dev Biol 12:15. 2012
    ..Despite the derived developmental modes, it appears more likely that conserved mechanisms can be found in anterior patterning...
  7. doi request reprint Segment polarity gene expression in a myriapod reveals conserved and diverged aspects of early head patterning in arthropods
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden
    Dev Genes Evol 222:299-309. 2012
    ..This feature is conserved in representatives of all arthropod classes suggesting that the mandibular segment may have a special function in anterior patterning...
  8. doi request reprint Gene expression patterns in an onychophoran reveal that regionalization predates limb segmentation in pan-arthropods
    Ralf Janssen
    Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36 Uppsala, Sweden
    Evol Dev 12:363-72. 2010
    ..The reversed hth and exd patterns in chelicerates and myriapods are therefore an apomorphy for this group, the Myriochelata, lending support to the Myriochelata and Tetraconata clades in arthropod phylogeny...
  9. doi request reprint An abnormally developed embryo of the pill millipede Glomeris marginata that lacks dorsal segmental derivatives
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
    Dev Genes Evol 221:351-5. 2011
    ..Whether the observed abnormalities are caused by mutation or are the result of otherwise disturbed early development is unclear...
  10. doi request reprint Evidence for Wg-independent tergite boundary formation in the millipede Glomeris marginata
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala, Sweden
    Dev Genes Evol 218:361-70. 2008
    ..The proposed mechanism is similar to the mechanism used to establish the AP boundary in Drosophila wings and ventral pleura...
  11. pmc Expression of myriapod pair rule gene orthologs
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, SE 752 36 Uppsala, Sweden
    Evodevo 2:5. 2011
    ..abstract:..
  12. pmc Expression of collier in the premandibular segment of myriapods: support for the traditional Atelocerata concept or a case of convergence?
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Villavägen 16, 752 36 Uppsala, Sweden
    BMC Evol Biol 11:50. 2011
    ..It was therefore assumed that the expression of col in myriapods would reflect the ancestral state like in crustaceans and chelicerates, i.e. absence from the premandibular/intercalary segment and hence no function in its formation...
  13. pmc The hatching larva of the priapulid worm Halicryptus spinulosus
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden
    Front Zool 6:8. 2009
    ..These findings may further help unravelling the phylogenetic position of the Priapulida within the Scalidophora and hence contribute to the elucidation of the nature of the ecdysozoan ancestor...
  14. pmc Gene expression suggests conserved aspects of Hox gene regulation in arthropods and provides additional support for monophyletic Myriapoda
    Ralf Janssen
    Department of Earth Sciences, Palaeobiology, Villavägen 16, SE 75236 Uppsala, Sweden
    Evodevo 1:4. 2010
    ..Of the two splice variants of Ubx/Antp only one could be isolated from myriapods, representing a possible further synapomorphy of the Myriapoda...
  15. doi request reprint Gene expression suggests conserved mechanisms patterning the heads of insects and myriapods
    Ralf Janssen
    Uppsala University, Department of Earth Sciences, Palaeobiology, Uppsala, Sweden
    Dev Biol 357:64-72. 2011
    ..This finding implies that the anterior patterning mechanism already existed in the last common ancestor of insects and myriapods...
  16. doi request reprint Early embryonic development of the priapulid worm Priapulus caudatus
    Sofia A Wennberg
    Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala 75236, Sweden
    Evol Dev 10:326-38. 2008
    ..Further study is required to reconstruct basal cleavage patterns in both this clade, and indeed, the Bilateria as a whole...