Are dicentric anaphase bridges formed by somatic recombination in X chromosome inversion heterozygotes of Drosophila melanogaster?
Mitotic recombination has been induced with X-rays in Drosophila melanogaster larvae and assayed later as twin mosaic spots on the adult tergites. With the use of the In(1)sc 4L sc 8R chromosome which lacks the nucleolar organizer and is marked with yellow (y) indirect evidence was obtained that mit...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1972 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/47364 |
| Acceso en línea: | http://hdl.handle.net/10261/47364 |
| Access Level: | acceso abierto |
| Palabra clave: | Drosophila melanogaster X-rays Chromosomes Heterozygotes |
| Sumario: | Mitotic recombination has been induced with X-rays in Drosophila melanogaster larvae and assayed later as twin mosaic spots on the adult tergites. With the use of the In(1)sc 4L sc 8R chromosome which lacks the nucleolar organizer and is marked with yellow (y) indirect evidence was obtained that mitotic recombination between ring and rod chromosomes results, in a majority of cases, in XO spots, bearing the rod-X only. This was concluded from the relative scarcity and small sizes of y NO- spots (uncovering the sc 4 sc 8 chromosome), compared to control sisters bearing an extra Y chromosome with its NO locus. Thus, dicentric chromatid bridges formed by mitotic recombination between the ring and rod chromosomes are probably eliminated at the next division. In In(1)sc 4 sc 8/f36a (rod/rod) females, no effect of the Y chromosome on the frequency and sizes of cross-over spots was observed. Either any dicentric chromatid bridges formed by recombination between inverted rod chromosomes fragment at division, with a centromeric piece going to each pole, or such bridges are not usually formed by recombination. The latter case would indicate that somatic pairing of homologues is not accurate in X chromosome inversion heterozygotes and consequently, that recombination yields aneuploid cells. Additional studies are cited which indicate that X chromosome heterozygotes for entire arm inversions may not pair in the typical loop at the time of mitotic recombination. |
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