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THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS

Recently metamorphosed female Xenopus laevis toads were injected with tritiated thymidine. Animals were kept at 20°C and were sacrificed 1–23 days after isotope injection. Radio-autographs of squash preparations of the ovaries were made. The progress of labeled germ cell nuclei was followed to obtai...

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Detalles Bibliográficos
Autores principales: Coggins, Lesley Watson, Gall, Joseph G.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1972
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2108647/
https://www.ncbi.nlm.nih.gov/pubmed/5009519
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author Coggins, Lesley Watson
Gall, Joseph G.
author_facet Coggins, Lesley Watson
Gall, Joseph G.
author_sort Coggins, Lesley Watson
collection PubMed
description Recently metamorphosed female Xenopus laevis toads were injected with tritiated thymidine. Animals were kept at 20°C and were sacrificed 1–23 days after isotope injection. Radio-autographs of squash preparations of the ovaries were made. The progress of labeled germ cell nuclei was followed to obtain information on the time course of early meiosis and extra-chromosomal DNA synthesis. Premeiotic S was estimated to take not more than 7 days. Leptotene takes 4 days, zygotene takes 5 days, and pachytene was estimated to be completed in about 18 days. The major period of amplification of the extrachromosomal DNA occurs in pachytene and takes about 13 days. A low level of synthesis was observed before and after this period, in zygotene and late pachytene-early diplotene, extending the total time for extrachromosomal DNA synthesis during meiosis to about 18 days. These data allowed the calculation to be made that one round of replication of the amplified DNA takes between 1.2 and 3.0 days. It was also found that in both oogonial and premeiotic interphases, the nucleolus-associated DNA shows asynchronous (probably late) labeling with respect to the chromosomes.
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spelling pubmed-21086472008-05-01 THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS Coggins, Lesley Watson Gall, Joseph G. J Cell Biol Article Recently metamorphosed female Xenopus laevis toads were injected with tritiated thymidine. Animals were kept at 20°C and were sacrificed 1–23 days after isotope injection. Radio-autographs of squash preparations of the ovaries were made. The progress of labeled germ cell nuclei was followed to obtain information on the time course of early meiosis and extra-chromosomal DNA synthesis. Premeiotic S was estimated to take not more than 7 days. Leptotene takes 4 days, zygotene takes 5 days, and pachytene was estimated to be completed in about 18 days. The major period of amplification of the extrachromosomal DNA occurs in pachytene and takes about 13 days. A low level of synthesis was observed before and after this period, in zygotene and late pachytene-early diplotene, extending the total time for extrachromosomal DNA synthesis during meiosis to about 18 days. These data allowed the calculation to be made that one round of replication of the amplified DNA takes between 1.2 and 3.0 days. It was also found that in both oogonial and premeiotic interphases, the nucleolus-associated DNA shows asynchronous (probably late) labeling with respect to the chromosomes. The Rockefeller University Press 1972-03-01 /pmc/articles/PMC2108647/ /pubmed/5009519 Text en Copyright © 1972 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Coggins, Lesley Watson
Gall, Joseph G.
THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS
title THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS
title_full THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS
title_fullStr THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS
title_full_unstemmed THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS
title_short THE TIMING OF MEIOSIS AND DNA SYNTHESIS DURING EARLY OOGENESIS IN THE TOAD, XENOPUS LAEVIS
title_sort timing of meiosis and dna synthesis during early oogenesis in the toad, xenopus laevis
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2108647/
https://www.ncbi.nlm.nih.gov/pubmed/5009519
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