Micromere formation and its evolutionary implications in the sea urchin
Natsuko Emura1, Mamiko Yajima1
1Department of Molecular Biology Cell Biology Biochemistry, Brown University, Providence, RI, United States.
Current Topics in Developmental Biology
|February 14, 2022
Summary
Sea urchin micromeres, arising from asymmetric cell division, act as early embryonic organizers. This unique cell lineage, likely a derived feature in echinoderm evolution, commits to specific fates while other cells remain plastic.
Area of Science:
- Developmental biology
- Evolutionary developmental biology
- Marine biology
Background:
- Micromeres are unique blastomeres in sea urchin embryos, originating from asymmetric cell division.
- Unlike other blastomeres, micromeres function as organizers and commit to specific cell fates early in development.
Purpose of the Study:
- To summarize historical and recent observations on the unique properties of sea urchin micromeres.
- To discuss the evolutionary origins of the micromere lineage in echinoderms.
Main Methods:
- Review of historical and recent scientific literature on sea urchin embryogenesis.
- Comparative analysis of developmental patterns within Echinodermata.
Main Results:
- Micromeres are critical organizers in early sea urchin embryogenesis.
- Micromeres commit to fates like skeletogenic and germ cells, unlike plastic neighboring blastomeres.
- The formation of micromeres is considered a derived trait in the evolution of Echinoidea.
Conclusions:
- Sea urchin micromeres possess unique organizing and cell-fate-committing properties.
- The micromere lineage is a derived feature in echinoderm evolution, suggesting developmental system modifications.
- Understanding micromere evolution provides insights into the diversification of developmental strategies in marine invertebrates.
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