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Abortive meiosis in the oogenesis of parthenogenetic Daphnia pulex
| Title: | Abortive meiosis in the oogenesis of parthenogenetic Daphnia pulex |
| Authors: | Hiruta, Chizue Browse this author | | Nishida, Chizuko Browse this author →KAKEN DB | | Tochinai, Shin Browse this author →KAKEN DB |
| Keywords: | Daphnia pulex | | Parthenogenesis | | Automixis | | Diploidy maintenance |
| Issue Date: | Nov-2010 |
| Publisher: | Springer Netherlands |
| Journal Title: | Chromosome Research |
| Volume: | 18 |
| Issue: | 7 |
| Start Page: | 833 |
| End Page: | 840 |
| Publisher DOI: | 10.1007/s10577-010-9159-2 |
| PMID: | 20949314 |
| Abstract: | Most daphnid species adopt parthenogenesis and sexual reproduction differentially in response to varied environmental cues, resulting in the production of diploid progenies in both cases. Previous studies have reportedly suggested that daphnids produce their parthenogenetic eggs via apomixis; the nuclear division of mature oocytes should be an equational division similar to somatic mitosis. However, it seems premature to conclude that this has been unequivocally established in any daphnids. Therefore, the objective of our research was to precisely reveal the process and mechanism of parthenogenetic oogenesis and maintenance of diploidy in Daphnia pulex through histology, karyology, and immunohistochemistry. We found that when a parthenogenetic egg entered the first meiosis, division was arrested in the early first anaphase. Then, two half-bivalents, which were dismembered from each bivalent, moved back to the equatorial plate and assembled to form a diploid equatorial plate. Finally, the sister chromatids were separated and moved to opposite poles in the same manner as the second meiotic division followed by the extrusion of one extremely small daughter cell (resembling a polar body). These results suggest that parthenogenetic D. pulex do not adopt typical apomixis. We hypothesize that D. pulex switches reproductive mode depending on whether the egg is fertilized or not. |
| Rights: | The final publication is available at www.springerlink.com |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/49185 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 栃内 新
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