Juliane Germer

Juliane Germer

Funktion/Function: Doktorandin
Betreuer/Supervisors: Prof. Dr. Daniel Jackson

Raum/Room: 2.157 / 2.OG
Tel./phone: ++49-(0)551-39 91296
Fax/facsimile: ++49(0)551-39 7918

Representatives of most metazoan clades are able to fabricate and deposit biominerals. The wide-spread appearance of this ability in the fossil record largely coincides with a rapid increase in metazoan morphological diversity, suggesting that the evolution of this ability was one key factor that supported the so called 'Cambrian explosion'. Despite this, little is known about the molecular mechanisms that direct skeleton (biomineral) formation in most metazoans. One important and unanswered question is what degree of genetic conservation exists in the metazoan ?skeletogenic toolkit'? To address this question the biomineralisation strategies of extant animals representing all branches of the tree of life must be investigated. One critical group that must be included in such an analysis is the Porifera (sponges) because they are considered to be the most ancient group of metazoan lineages and are among the first animals to display a 'biologically controlled' mode of biomineralisation.

During my PhD I will focus on the biomineralisation strategy employed by the calcifying demosponge Vaceletia. The skeletal microstructure of this sponge has clear similarities with a now extinct assemblage of demosponges, the Archaeocyatha. As the earth's first reef builders the Archaeocyatha began to leave evidence of biocalcification in the fossil record 530 million years ago. Mirroring the coral reefs of todays oceans, archaeocyaths were ecologically significant, widely distributed and taxonomically diverse. Vaceletia is now believed to be the only living lineage that constructs its skeleton in a sphinctozoan-like (archaeocyathid) way. These similarities with ancient biomineralising animals make Vaceletia an ideal representative of the Porifera, and therefore an excellent model with which to study the evolution of the molecular mechanisms of skeleton formation. The main aim of my PhD is to identify the core genetic mechanisms employed by Vaceletia to construct its skeleton, and to deepen our understanding of how the ability to biomineralise may have first arisen in sponges.

To achieve this aim I will use techniques such as transcriptomics, proteomics and bioinformatics to identify biomineralisation gene candidates. I will characterise the spatial expression profiles of these gene candidates using in situ hybridization, and will use a variety of histological and microscopy techniques to reconstruct the cellular processes that underlie skeleton formation in Vaceletia.

Short curriculum and Awards

Professional career

  • Since 04/2011 Doctoral student and research assistant at the Department of Geobiology, Geoscience Center, University of Göttingen; Supervisors: Prof. Dr. J. Reitner, Prof. Dr. V. Thiel
  • 11/2010 — 03/2011 Research assistant in the laboratory of Organic Geochemistry at the Geoscience Center, University of Göttingen
  • 05/2009 — 10/2010 Student research assistant in the laboratory of Organic Geochemistry at the Geoscience Center, University of Göttingen
  • 01/2008 — 01/2009 Abroad studies at the UNAM, Mexico
  • 10/2004 — 11/2010 Study of Biology at the University of Göttingen; Diploma degree in Biology; Diploma thesis: ”Sedimentary preservation of sponge derived lipid biomarker“
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Germer, J., Blumenberg, M., Reitner, J., Thiel, V.: Are poriferan biomarkers preserved in the geological record? A study on sponge fossils and sponge-rich sediments of various ages 25th International Meeting on Organic Geochemistry, Interlaken, Switzerland 18.-23.09.2011 KARL H.- V. & U. STAESCHE (2007): Über Riesenlandschildkrötenreste von den Philippinen.- Geol. Jb., Reihe B; Hannover. (in press)

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