Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae)
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| Natura: | Artículo científico |
| Lingua: | en |
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Academia Brasileira de Ciências
2003
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| _version_ | 1876480103238598656 |
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| author | Maria Luiza Beçak |
| author_facet | Maria Luiza Beçak |
| contents | Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae) Maria Luiza Beçak Willy Beçak Alexandre Pereira Multidisciplinaria (Ciencias Naturales y Exactas) snakes endomitosis somatic pairing diplochromosomes chromosome positioning The positioning of macrochromosomes of Bothrops jararaca and Bothrops insularis (Viperidae) was studiedin undistorted radial metaphases of uncultured cells (spermatogonia and oogonia) not subjected to spindleinhibitors. Colchicinized metaphases from uncultured (spleen and intestine) and cultured tissues (blood) werealso analyzed. We report two antagonic non-random chromosome arrangements in untreated premeiotic cells:the parallel configuration with homologue chromosomes associated side by side in the metaphase plate andthe antiparallel configuration having homologue chromosomes with antipolar distribution in the metaphasering. The antiparallel aspect also appeared in colchicinized cells. The spatial chromosome arrangementin both configurations is groupal size-dependent and maintained through meiosis. We also describe, inuntreated gonia cells, endomitosis followed by reductional mitosis which restores the diploid number. In B.jararaca males we observed that some gonad regions present changes in the meiotic mechanism. In this case,endoreduplicated cells segregate the diplochromosomes to opposite poles forming directly endoreduplicatedsecond metaphases of meiosis with the suppression of first meiosis. By a successive division, these cells formnuclei with one set of chromosomes. Chromosome doubling in oogonia is known in hybrid species and inparthenogenetic salamanders and lizards. This species also presented chromosome rearrangements leading toaneuploidies in mitosis and meiosis. It is suggested that somatic pairing, endomitosis, meiotic alterations, andchromosomal aberrations can be correlated processes. Similar aspects of nuclei configurations, endomitosisand reductional mitosis were found in other Viperidae and Colubridae species. 2003 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32775304 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.75 |
| format | Artículo científico |
| id | redalyc_32775304 |
| institution | Redalyc |
| language | en |
| publishDate | 2003 |
| publisher | Academia Brasileira de Ciências |
| spellingShingle | Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae) Maria Luiza Beçak Multidisciplinaria (Ciencias Naturales y Exactas) snakes endomitosis somatic pairing diplochromosomes chromosome positioning Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae) Maria Luiza Beçak Willy Beçak Alexandre Pereira Multidisciplinaria (Ciencias Naturales y Exactas) snakes endomitosis somatic pairing diplochromosomes chromosome positioning The positioning of macrochromosomes of Bothrops jararaca and Bothrops insularis (Viperidae) was studiedin undistorted radial metaphases of uncultured cells (spermatogonia and oogonia) not subjected to spindleinhibitors. Colchicinized metaphases from uncultured (spleen and intestine) and cultured tissues (blood) werealso analyzed. We report two antagonic non-random chromosome arrangements in untreated premeiotic cells:the parallel configuration with homologue chromosomes associated side by side in the metaphase plate andthe antiparallel configuration having homologue chromosomes with antipolar distribution in the metaphasering. The antiparallel aspect also appeared in colchicinized cells. The spatial chromosome arrangementin both configurations is groupal size-dependent and maintained through meiosis. We also describe, inuntreated gonia cells, endomitosis followed by reductional mitosis which restores the diploid number. In B.jararaca males we observed that some gonad regions present changes in the meiotic mechanism. In this case,endoreduplicated cells segregate the diplochromosomes to opposite poles forming directly endoreduplicatedsecond metaphases of meiosis with the suppression of first meiosis. By a successive division, these cells formnuclei with one set of chromosomes. Chromosome doubling in oogonia is known in hybrid species and inparthenogenetic salamanders and lizards. This species also presented chromosome rearrangements leading toaneuploidies in mitosis and meiosis. It is suggested that somatic pairing, endomitosis, meiotic alterations, andchromosomal aberrations can be correlated processes. Similar aspects of nuclei configurations, endomitosisand reductional mitosis were found in other Viperidae and Colubridae species. 2003 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32775304 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.75 |
| title | Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae) |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) snakes endomitosis somatic pairing diplochromosomes chromosome positioning |
| url | https://www.redalyc.org/articulo.oa?id=32775304 |