Phosphatized Polar Lobe-Forming Embryos from the Precambrian of Southwest China

In developing embryos of some extant spiralian animals, polar lobe formation is one of the symmetry-breaking mechanisms for segregation of maternal cytoplasmic substances to certain blastomeres and not others. Polar lobe formation leads to unique early cleavage morphologies that include trilobed, J-...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2006-06, Vol.312 (5780), p.1644-1646
Main Authors: Chen, Jun-Yuan, Bottjer, David J, Davidson, Eric H, Dornbos, Stephen Q, Gao, Xiang, Yang, Yong-Hua, Li, Chia-Wei, Li, Gang, Wang, Xiu-Qiang, Xian, Ding-Chang, Wu, Hung-Jen, Hwu, Yeu-Kuang, Tafforeau, Paul
Format: Article
Language:English
Subjects:
Animals
Annelida - embryology
Archaeology
Biological Evolution
Blastomeres
Blastomeres - cytology
China
Delta cells
Earth sciences
Earth, ocean, space
Embryo, Nonmammalian - anatomy & histology
Embryo, Nonmammalian - cytology
Embryogenesis
Embryonic Development
Embryos
Evolution
Exact sciences and technology
Fossils
Geologic Sediments
Invertebrate paleontology
Invertebrates - embryology
Mollusca - embryology
Mollusks
Paleontology
Phosphates
Platyhelminths - embryology
Precambrian strata
Synchrotron radiation
Zygotes
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Summary:In developing embryos of some extant spiralian animals, polar lobe formation is one of the symmetry-breaking mechanisms for segregation of maternal cytoplasmic substances to certain blastomeres and not others. Polar lobe formation leads to unique early cleavage morphologies that include trilobed, J-shaped, and five-lobed structures. Fossil embryos similar to modern lobeforming embryos are recognized from the Precambrian Doushantuo Formation phosphates, Weng'an, Guizhou Province, China. These embryos are abundant and form a developmental sequence comparable to different developing stages observed in lobe-forming embryos of extant spiralians. These data imply that lobe formation is an evolutionarily ancient process of embryonic specification.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1125964