| 1. |
- Boisvert, Catherine Anne
(författare)
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Vertebral Development of Modern Salamanders Provides Insights Into a Unique Event of Their Evolutionary History
- 2009
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Ingår i: Journal of Experimental Zoology. Part B-Molecular and Developmental Evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 312B:1, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- The origin of salamanders and their interrelationships to the two other modern amphibian orders (frogs and caecilians) are problematic owing to an 80-100 million year gap in the fossil record between the Carboniferous to the Lower Jurassic. This is compounded by a scarcity of adult skeletal characters linking the early representatives of the modern orders to their stem-group in the Paleozoic. The use of ontogenetic characters can be of great use in the resolution of these questions. Growth series of all ten modern salamander families (a 120 cleared and stained larvae) were examined for pattern and timing of vertebral elements chondrification and ossification. The primitive pattern is that of the neural arches developing before the centra, while the reverse represents the derived condition. Both the primitive and derived conditions are observed within the family Hynobiidae, whereas only the derived condition is observed in all other salamanders. This provides support to the claims that Hynobiidae is both the most basal of modern families and potentially polyphyletic (with Ranodon and Hybobius forming the most basal clade and Salamandrella being a part of the most derived Blade). This provides insight into a unique event in salamander evolutionary history and suggests that the developmental pattern switch occurred between the Triassic and the mid-Jurassic before the last major radiation. J. Exp. Zool. (Mol. Dev. Evol.) 31213:1-29, 2009. (C) 2008 Wiley-Liss, Inc.
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| 2. |
- Fischer, Antje H. L., et al.
(författare)
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ZOONET : perspectives on the evolution of animal form. Meeting report
- 2009
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Ingår i: Journal of Experimental Zoology. - Hoboken, N. J. : Wiley-Blackwell. - 0022-104X .- 1097-010X. ; 312B:7, s. 679-685
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Tidskriftsartikel (refereegranskat)abstract
- What drives evolution? This was one of the main questions raised at the final ZOONET meeting in Budapest, Hungary, in November 2008. The meeting marked the conclusion of ZOONET, an EU-funded Marie-Curie Research Training Network comprising nine research groups from all over Europe (Max Telford, University College London; Michael Akam, University of Cambridge; Detlev Arendt, EMBL Heidelberg; Maria Ina Arnone, Stazione Zoologica Anton Dohrn Napoli; Michalis Averof, IMBB Heraklion; Graham Budd, Uppsala University; Richard Copley, University of Oxford; Wim Damen, University of Cologne; Ernst Wimmer, University of Gottingen). ZOONET meetings and practical courses held during the past four years provided researchers from diverse backgrounds-bioinformatics, phylogenetics, embryology, palaeontology, and developmental and molecular biology-the opportunity to discuss their work under a common umbrella of evolutionary developmental biology (Evo Devo). The Budapest meeting emphasized in-depth discussions of the key concepts defining Evo Devo, and bringing together ZOONET researchers with external speakers who were invited to present their views on the evolution of animal form. The discussion sessions addressed four main topics: the driving forces of evolution, segmentation, fossils and phylogeny, and the future of Evo Devo.
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| 3. |
- Fritzsch, Guido, et al.
(författare)
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PCR Survey of Xenoturbella bocki Hox Genes
- 2008
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Ingår i: JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL). - : Wiley. ; 310B:3, s. 278-284
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Tidskriftsartikel (refereegranskat)abstract
- Xenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re-evaluation of the available published evidence of Hox genes in other basal deuterostomes.
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| 4. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Possibility of Mixed Progenitor Cells in Sea Star Arm Regeneration
- 2010
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Ingår i: Journal of Experimental Zoology Part B-Molecular and Developmental Evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 314B:6, s. 457-468
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Tidskriftsartikel (refereegranskat)abstract
- In contrast to most vertebrates, invertebrate deuterostome echinoderms, such as the sea star Asterias rubens, undergo regeneration of lost body parts. The current hypothesis suggests that differentiated cells are the main source for regenerating arm in sea stars, but there is little information regarding the origin and identity of these cells. Here, we show that several organs distant to the regenerating arm responded by proliferation, most significantly in the coelomic epithelium and larger cells of the pyloric caeca. Analyzing markers for proliferating cells and parameters indicating cell ageing, such as levels of DNA damage, pigment, and lipofuscin contents as well as telomere length and telomerase activity, we suggest that cells contributing to the new arm likely originate from progenitors rather than differentiated cells. This is the first study showing that cells of mixed origin may be recruited from more distant sources of stem/progenitor cells in a sea star, and the first described indication of a role for pyloric caeca in arm regeneration. Data on growth rate during arm regeneration further indicate that regeneration is at the expense of whole animal growth. We propose a new working hypothesis for arm regeneration in sea stars involving four phases: wound healing by coelomocytes, migration of distant progenitor cells of mixed origin including from pyloric caeca, proliferation in these organs to compensate for cell loss, and finally, local proliferation in the regenerating arm J. Exp. Zool. (Mol. Dev. Evol.) 3148:457-468, 2010. (C) 2010 Wiley-Liss, Inc.
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| 5. |
- Imperial, Julita S., et al.
(författare)
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Venomous auger snail Hastula (Impages) hectica (Linnaeus, 1758): Molecular phylogeny, foregut anatomy and comparative toxinology
- 2007
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Ingår i: Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 308B:6, s. 744-756
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Tidskriftsartikel (refereegranskat)abstract
- The > 10,000 living venomous marine snail species [superfamily Conoidea Fleming, 1822] include cone snails (Conus), the overwhelming focus of research. Hastula hectica (Linnaeus, 1758), a venomous snail in the family Terebridae Morch, 1852 was comprehensively investigated. The Terebridae comprise a major monophyletic group within Conoidea. H. hectica has a striking radular tooth to inject venom that looks like a perforated spear; in Conus, the tooth looks like a hypodermic needle. H. hectica venom contains a large complement of small disulfide-rich peptides, but with no apparent overlap with Conus in gene superfamilies expressed. Although Conus peptide toxins are densely post-translationally modified, no post-translationally modified amino acids were found in any Hastula venom peptide. The results suggest that different major lineages of venomous molluscs have strikingly divergent toxinological and venom-delivery strategies. J. Exp. Zool. (Mol. Deu. Euol.) 308B: 744- 756, 2007. (c) 2007 Wiley-Liss, Inc.
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| 6. |
- Johanson, Zerina, et al.
(författare)
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Fish fingers : digit homologues in sarcopterygian fish fins
- 2007
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Ingår i: Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 308B:6, s. 757-768
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Tidskriftsartikel (refereegranskat)abstract
- A defining feature of tetrapod evolutionary origins is the transition from fish fins to tetrapod limbs. A major change during this transition is the appearance of the autopod (hands, feet), which comprises two distinct regions, the wrist/ankle and the digits. When the autopod first appeared in Late Devonian fossil tetrapods, it was incomplete: digits evolved before the full complement of wrist/ankle bones. Early tetrapod wrists/ankles, including those with a full complement of bones, also show a sharp pattern discontinuity between proximal elements and distal elements. This suggests the presence of a discontinuity in the proximal-distal sequence of development. Such a discontinuity occurs in living urodeles, where digits form before completion of the wrist/ankle, implying developmental independence of the digits from wrist/ankle elements. We have observed comparable independent development of pectoral fin radials in the lungfish Neoceratodus (Osteichthyes: Sareopterygii), relative to homologues of the tetrapod limb and proximal wrist elements in the main fin axis. Moreover, in the Neoceratodus fin, expression of Hoxd13 closely matches late expression patterns observed in the tetrapod autopod. This evidence suggests that Neoceratodus fin radials and tetrapod digits may be patterned by shared mechanisms distinct from those patterning the proximal fin/limb elements, and in that sense are homologous. The presence of independently developing radials in the distal part of the pectoral (and pelvic) fin may be a general feature of the Sarcopterygii.
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| 7. |
- Kuehn, Emily, et al.
(författare)
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Segment number threshold determines juvenile onset of germline cluster expansion in Platynereis dumerilii
- 2022
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Ingår i: Journal of Experimental Zoology Part B. - : John Wiley & Sons. - 1552-5007 .- 1552-5015. ; 338:4, s. 225-240
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Tidskriftsartikel (refereegranskat)abstract
- Development of sexual characters and generation of gametes are tightly coupled with growth. Platynereis dumerilii is a marine annelid that has been used to study germline development and gametogenesis. P. dumerilii has germ cell clusters found across the body in the juvenile worms, and the clusters eventually form the gametes. Like other segmented worms, P. dumerilii grows by adding new segments at its posterior end. The number of segments reflect the growth state of the worms and therefore is a useful and measurable growth state metric to study the growth-reproduction crosstalk. To understand how growth correlates with progression of gametogenesis, we investigated germline development across several developmental stages. We discovered a distinct transition period when worms increase the number of germline clusters at a particular segment number threshold. Additionally, we found that keeping worms short in segment number, by manipulating environmental conditions or via amputations, supported a segment number threshold requirement for germline development. Finally, we asked if these clusters in P. dumerilii play a role in regeneration (as similar free-roaming cells are observed in Hydra and planarian regeneration) and found that the clusters were not required for regeneration in P. dumerilii, suggesting a strictly germline nature. Overall, these molecular analyses suggest a previously unidentified developmental transition dependent on the growth state of juvenile P. dumerilii leading to substantially increased germline expansion.
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| 8. |
- Roth, Christian, et al.
(författare)
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Evolution after gene duplication : Models, mechanisms, sequences, systems, and organisms
- 2007
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Ingår i: J EXP ZOOL PART B. - : Wiley. - 1552-5007 .- 1552-5015. ; 308B:1, s. 58-73
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Forskningsöversikt (refereegranskat)abstract
- Gene duplication is postulated to have played a major role in the evolution of biological novelty. Here, gene duplication is examined across levels of biological organization in an attempt to create a unified picture of the mechanistic process by which gene duplication can have played a role in generating biodiversity. Neofunctionalization and subfunctionalization have been proposed as important processes driving the retention of duplicate genes. These models have foundations in population genetic theory, which is now being refined by explicit consideration of the structural constraints placed upon genes encoding proteins through physical chemistry. Further, such models can be examined in the context of comparative genomics, where an integration of gene-level evolution and species-level evolution allows an assessment of the frequency of duplication and the fate of duplicate genes. This process, of course, is dependent upon the biochemical role that duplicated genes play in biological systems, which is in turn dependent upon the mechanism of duplication: whole genome duplication involving a co-duplication of interacting partners vs. single gene duplication. Lastly, the role that these processes may have played in driving speciation is examined.
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| 9. |
- Vargas, Alexander O, et al.
(författare)
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An Epigenetic Perspective on the Midwife Toad Experiments of Paul Kammerer (1880-1926)
- 2017
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Ingår i: Journal of Experimental Zoology Part B. - : John Wiley & Sons. - 1552-5007 .- 1552-5015. ; 328:1-2, s. 179-192
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Forskningsöversikt (refereegranskat)abstract
- Paul Kammerer was the most outstanding neo-Lamarckian experimentalist of the early 20th century. He reported spectacular results in the midwife toad, including crosses of environmentally modified toads with normal toads, where acquired traits were inherited in Mendelian fashion. Accusations of fraud generated a great scandal, ending with Kammerer's suicide. Controversy reignited in the 1970s, when journalist Arthur Koestler argued against these accusations. Since then, others have argued that Kammerer's results, even if real, were not groundbreaking and could be explained by somatic plasticity, inadvertent selection, or conventional genetics. More recently, epigenetics has uncovered mechanisms by which inheritance can respond directly to environmental change, inviting a reanalysis of Kammerer's descriptions. Previous arguments for mere somatic plasticity have ignored the description of experiments showing heritable germ line modification. Alleged inadvertent selection associated with egg mortality can be discarded, since mortality decreased in a single generation, upon repeated exposures. The challenging implications did not escape the attention of Kammerer's noted contemporary, William Bateson, but he reacted with disbelief, thus encouraging fraud accusations. Nowadays, formerly puzzling phenomena can be explained by epigenetic mechanisms. Importantly, Kammerer described parent-of-origin effects, an effect of parental sex on dominance. Epigenetic mechanisms underlie these effects in genomic imprinting and experiments of transgenerational epigenetic inheritance. In the early 20th century, researchers had no reason to link them with the inheritance of acquired traits. Thus, the parent-of-origin effects in Kammerer's experiments specifically suggest authenticity. Ultimate proof should come from renewed experimentation. To encourage further research, we present a model of possible epigenetic mechanisms.
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| 10. |
- Yang, Hai-Ling, et al.
(författare)
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The ligand Jelly Belly (Jeb) activates the Drosophila Alk RTK to drive PC12 cell differentiation, but is unable to activate the mouse ALK RTK
- 2007
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Ingår i: Journal of experimental zoology, part B Molecular and developmental evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 308:3, s. 269-282
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Tidskriftsartikel (refereegranskat)abstract
- The Drosophila Alk receptor tyrosine kinase (RTK) drives founder cell specification in the developing visceral mesoderm and is crucial for the formation of the fly gut. Activation of Alk occurs in response to the secreted ligand Jelly Belly. No homologues of Jelly Belly are described in vertebrates, therefore we have approached the question of the evolutionary conservation of the Jeb-Alk interaction by asking whether vertebrate ALK is able to function in Drosophila. Here we show that the mouse ALK RTK is unable to rescue a Drosophila Alk mutant, indicating that mouse ALK is unable to recognise and respond to the Drosophila Jeb molecule. Furthermore, the overexpression of a dominant-negative Drosophila Alk transgene is able to block the visceral muscle fusion event, which an identically designed dominant-negative construct for the mouse ALK is not. Using PC12 cells as a model for neurite outgrowth, we show here for the first time that activation of dAlk by Jeb results in neurite extension. However, the mouse Alk receptor is unable to respond in any way to the Drosophila Jeb protein in the PC12 system. In conclusion, we find that the mammalian ALK receptor is unable to respond to the Jeb ligand in vivo or in vitro. These results suggest that either (i) mouse ALK and mouse Jeb have co-evolved to the extent that mALK can no longer recognise the Drosophila Jeb ligand or (ii) that the mALK RTK has evolved such that it is no longer activated by a Jeb-like molecule in vertebrates.
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