Research Topics
| Ralf JanssenSummaryAffiliation: Uppsala University Country: Sweden Publications
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Detail Information
Publications
Developmental abnormalities in Glomeris marginata (Villers 1789) (Myriapoda: Diplopoda): implications for body axis determination in a myriapodRalf 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...- Diplosegmentation in the pill millipede Glomeris marginata is the result of dorsal fusionRalf 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... 
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...- Segment polarity gene expression in a myriapod reveals conserved and diverged aspects of early head patterning in arthropodsRalf 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... - An abnormally developed embryo of the pill millipede Glomeris marginata that lacks dorsal segmental derivativesRalf 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... - Gene expression suggests conserved mechanisms patterning the heads of insects and myriapodsRalf 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... - Expression of myriapod pair rule gene orthologsRalf Janssen
Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, SE 752 36 Uppsala, Sweden
Evodevo 2:5. 2011..abstract:.. - 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... - Gene expression suggests conserved aspects of Hox gene regulation in arthropods and provides additional support for monophyletic MyriapodaRalf 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... - Gene expression patterns in an onychophoran reveal that regionalization predates limb segmentation in pan-arthropodsRalf 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... - The hatching larva of the priapulid worm Halicryptus spinulosusRalf 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... - Evidence for Wg-independent tergite boundary formation in the millipede Glomeris marginataRalf 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... - Conservation, loss, and redeployment of Wnt ligands in protostomes: implications for understanding the evolution of segment formationRalf 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... - Early embryonic development of the priapulid worm Priapulus caudatusSofia 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...