Structure and evolution of CyI cytoplasmic actin-encoding genes in the indirect- and direct-developing sea urchins Heliocidaris tuberculata and Heliocidaris erythrogramma

Gene ◽  
1995 ◽  
Vol 153 (2) ◽  
pp. 219-224 ◽  
Author(s):  
Jang-Hee Hahn ◽  
Jessica C. Kissinger ◽  
Rudolf A. Raff
Keyword(s):  
Sea Urchins ◽  
Heliocidaris Erythrogramma ◽  
Cytoplasmic Actin ◽  
Heliocidaris Tuberculata ◽  
Encoding Genes

scholarly journals Evolution of abbreviated development in Heliocidaris erythrogramma dramatically re-wired the highly conserved sea urchin developmental gene regulatory network to decouple signaling center function from ultimate fate

2019 ◽  
Author(s):  
Allison Edgar ◽  
Maria Byrne ◽  
David R. McClay ◽  
Gregory A. Wray
Keyword(s):  
Early Development ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Sea Urchins ◽  
Stabilizing Selection ◽  
Developmental Gene ◽  
Heliocidaris Erythrogramma ◽  
Signaling Center ◽  
Gene Regulatory ◽  
Ultimate Fate

AbstractDevelopmental gene regulatory networks (GRNs) describe the interactions among gene products that drive the differential transcriptional and cell regulatory states that pattern the embryo and specify distinct cell fates. GRNs are often deeply conserved, but whether this is the product of constraint inherent to the network structure or stabilizing selection remains unclear. We have constructed the first formal GRN for early development in Heliocidaris erythrogramma, a species with dramatically accelerated, direct development. This life history switch has important ecological consequences, arose rapidly, and has evolved independently many times in echinoderms, suggesting it is a product of selection. We find that H. erythrogramma exhibits dramatic differences in GRN topology compared with ancestral, indirect-developing sea urchins. In particular, the GRN sub-circuit that directs the early and autonomous commitment of skeletogenic cell precursors in indirect developers appears to be absent in H. erythrogramma, a particularly striking change in relation to both the prior conservation of this sub-circuit and the key role that these cells play ancestrally in early development as the embryonic signaling center. These results show that even highly conserved molecular mechanisms of early development can be substantially reconfigured in a relatively short evolutionary time span, suggesting that selection rather than constraint is responsible for the striking conservation of the GRN among other sea urchins.

scholarly journals Growth and age structure of sea urchins (Heliocidaris erythrogramma) in complex barrens and native macroalgal beds in eastern Tasmania

2007 ◽  
Vol 65 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Hugh G. Pederson ◽  
Craig R. Johnson
Keyword(s):  
Sea Urchin ◽  
Age Structure ◽  
Sea Urchins ◽  
Growth Models ◽  
Resource Limitation ◽  
Small Scale ◽  
Frequency Distributions ◽  
Heliocidaris Erythrogramma ◽  
Community Types ◽  
Size At Age

Abstract Pederson, H. G., and Johnson, C. R. 2008. Growth and age structure of sea urchins (Heliocidaris erythrogramma) in complex barrens and native macroalgal beds in eastern Tasmania. – ICES Journal of Marine Science, 65: 1–11. The formation of small-scale barrens of sea urchins on the east coast of Tasmania allows for direct comparison of the growth rates and age structures of sea urchin populations in barrens and habitats dominated by native macroalgae. However, such barrens are atypical of any previously described in temperate regions worldwide mainly because of the establishment and seasonal colonization by the introduced macroalga Undaria pinnatifida. Growth models were fitted to sea urchin (Heliocidaris erythrogramma) data, based on tag-recapture information from two distinct community types, a native macroalgal bed and a sea urchin barren colonized by U. pinnatifida. Despite the distinct contrast in habitats, size-at-age relationships and age frequency distributions were not significantly different between the two populations. However, the relationship between jaw length and test diameters was significantly different between populations, sea urchins in barrens possessing larger jaws relative to conspecifics of similar test diameter in native macroalgal habitats. It is proposed that the growth of sea urchins on barrens is not adversely affected by the loss of native macroalgae in the presence of U. pinnatifida. However, sea urchins display a level of resource limitation in barrens because of differences in the relationships of sea urchin morphometrics.

Variation in abundances of herbivorous invertebrates in temperate subtidal rocky reef habitats

2004 ◽  
Vol 55 (1) ◽  
pp. 93 ◽  
Author(s):  
Mathew A. Vanderklift ◽  
Gary A. Kendrick
Keyword(s):  
Sea Urchin ◽  
Western Australia ◽  
Sea Urchins ◽  
Habitat Partitioning ◽  
Rocky Reef ◽  
Heliocidaris Erythrogramma ◽  
A Minor ◽  
Different Parts ◽  
Over Time ◽  
Rock Faces

The present study assessed variation in the abundances of large herbivorous invertebrates in south-western Australia. There was some habitat partitioning between different parts of the reef: of the most frequently recorded species, the sea urchins Phyllacanthus irregularis and Centrostephanus tenuispinus were found primarily at the base of steep rock faces, whereas the gastropods Turbo torquatus and Australium squamifera were found primarily on open sections of reef. The sea urchin Heliocidaris erythrogramma was evenly distributed between these two habitats. For C. tenuispinus and H. erythrogramma, differences among locations (separated by tens to hundreds of kilometers) were the main source of variation in abundances. Phyllacanthus irregularis was more evenly distributed among locations. Abundances of sea urchins at each reef varied little over 26 months, suggesting low mortality and low recruitment. Turbo torquatus and A. squamifera varied significantly in abundance among reefs separated by < 10 km, although these differences were influenced by fluctuations over time. Broad patterns in abundances were evident: overall, abundances of herbivorous invertebrates were low, but certain areas supported high abundances. This suggests that herbivory may be a minor process in this region; however, the importance of herbivory at reefs with and without high abundances of herbivores deserves further attention.

Population structure of the purple sea urchin Heliocidaris erythrogramma along a latitudinal gradient in south-west Australia

2013 ◽  
Vol 94 (5) ◽  
pp. 1033-1040 ◽  
Author(s):  
Dan A. Smale ◽  
Thomas Wernberg
Keyword(s):  
Sea Urchin ◽  
Survey Design ◽  
Sea Urchins ◽  
Gonad Index ◽  
Population Level ◽  
Habitat Types ◽  
Heliocidaris Erythrogramma ◽  
Purple Sea Urchin ◽  
South West ◽  
Size Condition

Sea urchins are key herbivores in many coastal ecosystems. The purple sea urchin, Heliocidaris erythrogramma, is widely distributed across temperate Australia where it exhibits considerable plasticity in feeding behaviour and ecophysiology. In this study we examined H. erythrogramma populations on subtidal reefs along ~4° of latitude in south-west Australia. We used a multi-factorial survey design to assess variability in H. erythrogramma abundances between locations (>200 km part), sites (≥1 km apart) and habitat types (reef flats and slopes). We also examined spatial variability in urchin size, condition (measured by gonad index), and the relative abundances of two co-occurring subspecies. Urchin densities were generally low and did not vary between locations, but did vary between habitat types and amongst sites. Site-level variability in urchin size and condition was also pronounced. The southernmost population comprised smaller individuals and greater relative abundance of the H. e. erythrogramma subspecies, which is abundant on the east coast of Australia. We observed no indication of population-level responses to a recent extreme warming event that impacted the wider ecology of the region, but further investigation into the effects of both gradual warming and short-term climatic events on the ecology of H. erythrogramma and other key herbivores is required.

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