Submitted EMBO course application (MAMED 2013)


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Abstract

Also at Google Docs.

Expression of engrailed and wnt1 demarcates the anterior lobe boundary in a brachiopod larva
Bruno C. Vellutini and Andreas Hejnol
Sars International Centre for Marine Molecular Biology, Bergen, Norway

Segmentation of the body along the anterior-posterior (AP) axis is a characteristic feature of arthropods, annelids, and chordates. It is a long standing question whether segmentation had a common evolutionary origin or if it has evolved multiple times in bilaterians. Regulatory mechanisms of segmentation can be surprisingly conserved across taxa (e.g., segment polarity genes), but can also vary even within related groups (e.g., different annelids). Brachiopods are sessile spiralians with a bivalved shell closely related to annelids, molluscs, and nemerteans. Despite having an unsegmented adult body, the larval body of many brachiopods is divided in two or three lobes disposed along the AP axis. They are denominated apical, mantle, and pedicle lobes and define an anterior and a posterior boundary in the trilobed larvae. The objective of this study is to verify if segment polarity genes have a role in the development of the larval lobes of brachiopods. Therefore we have cloned and performed in situ hybridizations of engrailed, wnt genes, and components of the Hedgehog pathway in different developmental stages of the brachiopod Terebratalia transversa. We detected transverse stripes of wnt1 and engrailed transcripts adjacent to each other at the anterior boundary of the larva. wnt1 is localized along the posterior-most region of the apical lobe and engrailed along the anterior-most region of the mantle lobe. This expression is similar to the patterns found at parasegment and segment boundaries of arthropods and annelids, respectively. Thus, our preliminary results suggest that engrailed and wnt1 are involved in forming and maintaining the anterior boundary of T. transversa larvae. Succeeding functional experiments will help to clarify the degree of conservation of such segmentation mechanism during brachiopod development.

Motivation

Also at Google Docs.

Dear admissions committee,

I am a PhD student in Andreas Hejnol’s group at the Sars Centre for Marine Molecular Biology and associated to the Molecular and Computational Biology Research School of University of Bergen, Norway. My general research goal is to understand how changes in organism development are related to the evolution of form in metazoans. I am interested in evo-devo of less studied marine invertebrates especially concerning the evolution of larval body patterns.

It was the work of the 19th century Russian biologist Élie Metchnikoff that triggered my current interest for marine invertebrates and developmental processes. His career was based on comparative embryological studies of invertebrates and on a compelling evolutionary thinking which influenced me during my undergraduate studies. This early contact to exciting evolutionary questions involving the evolution of multicellularity and ontogenetic processes directed my attention towards evolutionary developmental biology. Since then, the interface between evolution and development became the main axis of my academic pursuit.

Before starting my master’s thesis I had the opportunity to take two courses at Friday Harbor Laboratories. The practical contact with the wide diversity of embryonic and larval forms of marine invertebrates as well as the enlightening discussions about evolution and development had a major influence on my project. For my master’s thesis I investigated the developmental origins of the morphology of sea biscuits and sand dollars. I established a detailed morphological description from fertilization to late juvenile stages of a tropical sea biscuit species with emphasis on the juvenile patterning. During the project I gained experience with documentation techniques for live samples with light microscopy using photography, video, and timelapse imaging. I also experimented with 3D reconstruction which sparkled my interest for image processing and programming.

Having a strict morphological background I felt the necessity of expanding my approaches for evo-devo research with molecular techniques and gene expression studies as well as more advanced imaging techniques. In my PhD position at the Hejnol Lab I am working with the evolution of larval body patterns using a comparative approach with non-model marine invertebrates such as bryozoans, brachiopods, and nemerteans. My project includes a survey for segmentation mechanisms in brachiopod larvae and identifying the origin and fate of pluripotent larval tissues in different spiralian species. I am mainly using gene expression patterns of candidate genes and confocal imaging.

The course “Marine animal models in evolution & development” fits my immediate research interests in several aspects. Because of my inclination for comparative studies developing a solid set of skills for establishing molecular techniques and genomic resources of new organisms is paramount. Getting insights about in situ hybridization and antibody staining as well as the analysis of gene expression patterns and gene regulatory networks will be extremely useful for my current PhD projects. I also have a strong interest for experimenting with more advanced imaging techniques, specially SPIM, since they make a crucial aspect of development accessible to us, the dynamics of ontogenetic processes.

Other topics offered that I want to incorporate to my research repertoire, but have no previous experience include functional approaches and its many techniques such as microinjection of embryos, gene knockdown, transgenesis, and other reverse genetics methods. Having a primer during the course will certainly be of good value for developing future projects.

Finally, I am excited to explore the fjord diversity and particularly attracted by the scheduled discussions which will provide grounds and stimuli for new research ideas and positively impact my work. This EMBO Practical Course is definitely aligned with my career goals and is a perfect opportunity to learn and be up-to-date with several state-of-art methods in evo-devo.

Best regards,

Bruno

CV

Sent this one.

Referees contacts

Andreas Hejnol
Group leader
Sars International Centre for Marine Molecular Biology
andreas.hejnol@sars.uib.no
Tlf (47) 55 58 43 28
Fax (47) 55 58 43 05

Alvaro Esteves Migotto
Professor
Marine Biology Center of University of São Paulo
aemigott@usp.br
Tlf (55 12) 3862 8416
Fax (55 12) 3862 8454
I’m searching for developmental data and patterns of marine invertebrates which may add
new insights on how and why metazoan evolved.

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