Cytogenetic studies in Sinipta dalmani Stål (Orthoptera: Acrididae). II. Effects of centric fusions on chiasma frequency and distribution
Spontaneous and polymorphic centric fusions were detected in a population of Sinipta dalmnni (2n: 23, XO male/XX female) from Entre Rios Province (Argentina). The spontaneous rearrangement affects 2 autosomes (M6 and M7) while the polymorphic one involves the sex chromosome and the fifth member of t...
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_0999193X_v22_n3_p263_Remis |
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| Sumario: | Spontaneous and polymorphic centric fusions were detected in a population of Sinipta dalmnni (2n: 23, XO male/XX female) from Entre Rios Province (Argentina). The spontaneous rearrangement affects 2 autosomes (M6 and M7) while the polymorphic one involves the sex chromosome and the fifth member of the complement. The former has irregular behaviour presenting a high frequency of non disjunctional orientation during metaphase I. This mutation does not affect either the frequency or the distribution of chiasmata in the bivalents involved. However, the polymorphic fusion has a significant influence on chiasma distribution, since an increment in the distal chiasma frequency in the affected bivalent was observed. These results indicate that the polymorphic mutation has an effect on intrachromosomal recombination, which would have adaptive significance, in contrast with the situation of spontaneous fusion which rarely persists in the population. © Elsevier/INRA. |
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