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- Koutsouveli, Vasiliki
(author)
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Sex, Molecules, and Gene control : Ecophysiological and evolutionary aspects of key sponge species from Antarctic shallow waters and the deep sea
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Very little is known about the ecophysiological aspects of Porifera (sponges) from Antarctica and North Atlantic, even though they are keystone components of these habitats. Being the earliest diverging metazoan lineage, sponges also play a fundamental role in our understanding of animal evolution. The main focus of this thesis was to study several aspects of the reproduction of sponges from the Antarctic shallow waters and the North Atlantic deep-sea sponge grounds and to describe the molecular toolkit that regulates their gametogenesis from an evolutionary perspective.In paper I, the reproductive strategy of six demosponge species commonly found in the shallow waters of Antarctica was examined with histological analyses. All species were brooders and although they reproduced during similar periods of the year, differences in their reproductive strategies might have allowed their coexistence in a habitat with annual food limitation events and low temperature.In paper II, the reproductive strategy of five species of the genus Geodia, a keystone genus of boreo-arctic sponge grounds, was assessed with histological analyses. All species were gonochoristic and oviparous, reproducing during similar periods (1-2 cycles annually) and with a high reproductive effort. The abundant lipid yolk and bacterial symbionts in their oocytes might enhance embryonic survival in the water column. Slight differences in reproductive strategies among species indicate specific adaptations for their successful colonization. This is the most detailed description of the reproductive biology of deep-sea Geodia sponges, providing essential information for the design of adequate conservation strategies in these vulnerable areas.In paper III, the genes and proteins regulating the oogenesis and spermatogenesis of the same five Geodia spp. were identified with RNA-seq and proteomic analyses and it was concluded that the molecular toolkit behind the main stages of gametogenesis is conserved across Metazoa. This is the most comprehensive molecular study on the gametogenesis of sponges and has profound implications for understanding the evolution of sexual reproduction in animals.In Manuscript IV, the reproductive features, the lipid signals and the accompanying gene expression patterns during oogenesis of the keystone deep-sea sponge Phakellia ventilabrum were assessed with histological, lipidomic and RNA-seq analyses. In this oviparous species, most of the triacylglycerides showed a tendency for signal increase during oogenesis, correlated with significant overexpression of genes related to their biosynthesis. This might suggest that triacylglyceride-rich yolk is the main lipid storage for the future embryo. This study unveils lipid metabolism patterns associated with female reproduction in sponges for the first time, setting the basis for a better understanding of the chemical ecology of this species and for future comparative analyses across species.
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| 2. |
- Moczek, Armin P., et al.
(author)
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The significance and scope of evolutionary developmental biology : a vision for the 21st century
- 2015
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In: Evolution & development. ; 17:3, s. 198-219
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Journal article (peer-reviewed)abstract
- Evolutionary developmental biology (evo-devo) has undergone dramatic transformations since its emergence as a distinct discipline. This paper aims to highlight the scope, power, and future promise of evo-devo to transform and unify diverse aspects of biology. We articulate key questions at the core of eleven biological disciplines-from Evolution, Development, Paleontology, and Neurobiology to Cellular and Molecular Biology, Quantitative Genetics, Human Diseases, Ecology, Agriculture and Science Education, and lastly, Evolutionary Developmental Biology itself-and discuss why evo-devo is uniquely situated to substantially improve our ability to find meaningful answers to these fundamental questions. We posit that the tools, concepts, and ways of thinking developed by evo-devo have profound potential to advance, integrate, and unify biological sciences as well as inform policy decisions and illuminate science education. We look to the next generation of evolutionary developmental biologists to help shape this process as we confront the scientific challenges of the 21st century.
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| 3. |
- Schwager, Evelyn E., et al.
(author)
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The house spider genome reveals an ancient whole-genome duplication during arachnid evolution
- 2017
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In: BMC Biology. - : BIOMED CENTRAL LTD. - 1741-7007. ; 15
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Journal article (peer-reviewed)abstract
- Background: The duplication of genes can occur through various mechanisms and is thought to make a major contribution to the evolutionary diversification of organisms. There is increasing evidence for a large-scale duplication of genes in some chelicerate lineages including two rounds of whole genome duplication (WGD) in horseshoe crabs. To investigate this further, we sequenced and analyzed the genome of the common house spider Parasteatoda tepidariorum.Results: We found pervasive duplication of both coding and non-coding genes in this spider, including two clusters of Hox genes. Analysis of synteny conservation across the P. tepidariorum genome suggests that there has been an ancient WGD in spiders. Comparison with the genomes of other chelicerates, including that of the newly sequenced bark scorpion Centruroides sculpturatus, suggests that this event occurred in the common ancestor of spiders and scorpions, and is probably independent of the WGDs in horseshoe crabs. Furthermore, characterization of the sequence and expression of the Hox paralogs in P. tepidariorum suggests that many have been subject to neo-functionalization and/or sub-functionalization since their duplication.Conclusions: Our results reveal that spiders and scorpions are likely the descendants of a polyploid ancestor that lived more than 450 MYA. Given the extensive morphological diversity and ecological adaptations found among these animals, rivaling those of vertebrates, our study of the ancient WGD event in Arachnopulmonata provides a new comparative platform to explore common and divergent evolutionary outcomes of polyploidization events across eukaryotes.
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