Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)

In a previous study (Vilardi 1983, 1985) a polymorphism for a mitotically and meiotically unstable B chromosome was detected in a population of Dichroplus elongatus from Tucumán (República Argentina). In the present work a detailed analysis of four B carrying individuals from the same population is...

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Publicado: 1986
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00087114_v39_n3-4_p287_Remis
http://hdl.handle.net/20.500.12110/paper_00087114_v39_n3-4_p287_Remis
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_00087114_v39_n3-4_p287_Remis2023-06-08T14:33:14Z Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae) In a previous study (Vilardi 1983, 1985) a polymorphism for a mitotically and meiotically unstable B chromosome was detected in a population of Dichroplus elongatus from Tucumán (República Argentina). In the present work a detailed analysis of four B carrying individuals from the same population is reported. The B’s within an individual were generally telocentric, their number varying from 0 to 6. In some cells, B’s were metacentric or acrocentric because of spontaneous rearrangements. At diplotene and diakinesis they could form univalents or pair, in general terminally, rendering bivalents or paseudomultivalents. At first metaphase only univalents or terminally associated B bivalents were observed. These bivalents could persist even to first anaphase migrating undivided to the same pole. Interstitial chiasma frequency and the ratio interstitial/total chiasmata per cell showed an apparent increase as the number of B’s per cell were incremented, without significant changes in the total number of chiasmata per cell. The regressions of interstitial chiasma frequency and interstitial/total chiasmata per cell on the number of B’s per cell were highly significant (p < 0.01). These results would indicate that the B’s may influence genetic recombination without changing the total chiasma frequency. The fact of conferring a higher degree of variability in the offspring of B carrying individuals might be one of the causes for the maintenance of these B’s in the population. © 1986 Taylor & Francis Group, LLC. 1986 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00087114_v39_n3-4_p287_Remis http://hdl.handle.net/20.500.12110/paper_00087114_v39_n3-4_p287_Remis
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description In a previous study (Vilardi 1983, 1985) a polymorphism for a mitotically and meiotically unstable B chromosome was detected in a population of Dichroplus elongatus from Tucumán (República Argentina). In the present work a detailed analysis of four B carrying individuals from the same population is reported. The B’s within an individual were generally telocentric, their number varying from 0 to 6. In some cells, B’s were metacentric or acrocentric because of spontaneous rearrangements. At diplotene and diakinesis they could form univalents or pair, in general terminally, rendering bivalents or paseudomultivalents. At first metaphase only univalents or terminally associated B bivalents were observed. These bivalents could persist even to first anaphase migrating undivided to the same pole. Interstitial chiasma frequency and the ratio interstitial/total chiasmata per cell showed an apparent increase as the number of B’s per cell were incremented, without significant changes in the total number of chiasmata per cell. The regressions of interstitial chiasma frequency and interstitial/total chiasmata per cell on the number of B’s per cell were highly significant (p < 0.01). These results would indicate that the B’s may influence genetic recombination without changing the total chiasma frequency. The fact of conferring a higher degree of variability in the offspring of B carrying individuals might be one of the causes for the maintenance of these B’s in the population. © 1986 Taylor & Francis Group, LLC.
title Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)
spellingShingle Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)
title_short Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)
title_full Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)
title_fullStr Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)
title_full_unstemmed Meiotic behaviour and dosage effect of B-Chromosomes on recombination in Dichroplus Elongatus (Orthoptera: Acrididae)
title_sort meiotic behaviour and dosage effect of b-chromosomes on recombination in dichroplus elongatus (orthoptera: acrididae)
publishDate 1986
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00087114_v39_n3-4_p287_Remis
http://hdl.handle.net/20.500.12110/paper_00087114_v39_n3-4_p287_Remis
_version_ 1768543114644946944

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