Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Cytogenetic studies in Sinipta dalmani Stål | 263 Genet Sei Evol 1990 22 263-272 Elsevier INRA Original article . Cytogenetic studies in Sinipta dalmani stậl Orthoptera acrididae . II. Effects of centric fusions on chiasma frequency and distribution MI Remis ưníversidad de Buenos Aires Facultad de Ciencias Exactas y Naturales - . Departamento de Ciencias Bioldgicas . Intendente Gũiraldes y Costanera Norte 1 28 Buenos Aires Argentina Received 25 January 1989 accepted 23 April 1990 Summary - Spontaneous and polymorphic centric fusions were detected in a population of Sinipta dalmani 2n 23 xo male xx female from Entre Rios Province Argentina . The spontaneous rearrangement affects 2 autosomes Mg 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. orthoptera chiasma centric fusion Resume Etudes cytogénétiques chez la sauterelle Sinipta dalmani Stãl Orthoptera acrididae . II. Effets des fusions centriques sur la fréquence et la distribution des chiasmas. Des fusions centriques spontanée et polymorphe ont été détectées dans une population de Sinipta dalmani 2a 23 males xo femelles XX de la province d Entre Rios Argentine . Le rearrangement spontané affecte 2 autosomes Ms et Mt tandis que la fusion polymorphe implique le chromosome sexuel et le 5s autosome Ms . La premiere fusion présente un comportement irregulier OÙ le chromosome Ịusionụé Ms 7 .
