Origin of Animal diversity considered from the early development of chaetognaths
| Project/Area Number |
11640695
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
系統・分類
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| Research Institution | Mie University |
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Principal Investigator |
GOTO Taichiro Mie University, Faculty of Education, Associate Professor, 教育学部, 助教授 (90183813)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | chaetognath / body axes / developmental fate / tetrahedral four-cell stage / spiralians / germ plasm / カエデイソヤムシ / 8細胞期胚 / らせん卵割 |
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| Research Abstract |
To elucidate developmental fates, single blastomeres of the four-celled and eight-celled embryos of Paraspadella gotoi were injected with a lineage-tracing dye. The distribution of the labels was observed in the hatchlings. The four-celled embryo consists of the animal and vegetal cross-furrow cells in a tetrahedral arrangement and one of the vegetal cross-furrow cells typically contains the germ plasm. When single cells were injected at the four-cell stage, four labeling patterns were observed (D, V, L and R). Injection at the eight-cell stage revealed eight labeling patterns which represent subsets of the four patterns observed in the hatchling injected at four-cell stage. The V pattern is probably generated from the blastomere containing the germ plasm. We found that the positions of the blastomeres at the four-cell stage correspond to the future body axes which is similar to classic spiralians and modified spiralians such as crustaceans. Furthermore, we confirmed that second cleavage occurs in a leiotropic fashion which is seen in the second cleavage of the classic spiralians. Labeled regions at the eight-cell stage were also examined at the gastrula and the hatchling of the same embryos. Most of body muscles were generated from the wall of the archenteron. This result supports the classical idea on the mesoderm formation of chaetognaths. The third cleavage divides the embryo into animal and vegetal halves. As gastrulation occurs from the vegetal region, the animal and vegetal cells produce the anterior and posterior regions of the body, respectively. The arrangement of the blastomeres corresponds to the body axis and the presumptive areas of the germ layers arrange along the animal-vegetal axis in chaetognaths. These are common characteristics among the triploblastica.
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Report
(3 results)
Research Products
(3 results)
