Meiotic Behaviour and Dosage Effect of B-Chromosomes on Recombination in Dichroplus Elongatus (Orthoptera: Acrididae)

@article{Remis1986MeioticBA,
  title={Meiotic Behaviour and Dosage Effect of B-Chromosomes on Recombination in Dichroplus Elongatus (Orthoptera: Acrididae)},
  author={M. I. Remis and J. Vilardi},
  journal={Caryologia},
  year={1986},
  volume={39},
  pages={287-301}
}
SUMMARYIn a previous study (Vilardi 1983, 1985) a polymorphism for a mitotically and meiotically unstable B chromosome was detected in a population of Dicbroplus elongatus from Tucuman (Republica 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… Expand
Supernumerary heterochromatin, chiasma conditions and abnormal sperm formation in Dichroplus elongatus (Orthoptera): intra and interpopulation analysis
TLDR
The cytophotometric analysis of DNA content revealed that in both types of males, B and non B carriers, most macrospermatids are diploid suggesting a probably origin by cytokinesi... Expand
Parallel polymorphisms for supernumerary heterochromatin in Dichroplus elongatus (Orthoptera):
TLDR
B individuals present an increase of abnormal spermatid frequency which may be explained by the simultaneous occurrence of two mechanisms: 1) lagging of supernumeraries and 2) physiological effects of B's affecting the meiosis even in cells lacking them. Expand
Effects of supernumerary heterochromatin on chiasma condition in two species of Acrididae (Orthoptera)
TLDR
A supernumerary terminal segment in S10 pair was observed in a heterozygous condition in several individuals of D. elongatus and has an intrachromosomal effect since it modifies the location of chiasmata in the bivalent involved. Expand
On the origin of B-chromosomes: neo XY systems and X-like supernumeraries in Orthoptera
TLDR
It is pointed out that small Bs could originate from polysomy of the smallest chromosomes, tolerated because of the few genes involved in Cylindrotettix obscurus, and the minute-B category is attributed to residua... Expand
Effects of B-Chromosomes on Recombination in Cylinbrotettix Obscurus (Leptysminae: Acrididae)
TLDR
87 male individuals of C. obscurus from Misiones, Argentina, were analysed for total (T), proximal (P), interstitial (I) and distal (D) chiasma frequency with the aim of detecting effects of those B-chromosomes on recombination in this species. Expand
Supernumerary Chromosome Variants in Dichroplus elongatus (Acrididae): Fluorescent Banding and Cline Variation Pattern
TLDR
Dichroplus elongatus is a South American grasshopper that shows simultaneous polymorphisms for B chromosomes and several supernumerary segments located in chromosome pairs S10, S9, and M6, in natural populations from Argentina, and the pattern of chromosome variation is discussed in relation to the population's ability to maintain supern numerical DNA in more climatically favorable geographic regions. Expand
Effects of centric-shift polymorphisms on chiasma conditions inTrimerotropis pallidipennis (Oedipodinae:Acrididae)
TLDR
Two populations ofTrimerotropis pallidipennis from Mendoza and Uspallata (UA) (Argentina), polymorphic with respect to centric shifts and B-chromosomes, were cytologically analysed and showed a clear tendency towards chiasma localisation and a redistribution of chiasmata, which could increase genetic recombination. Expand
Non Random Distribution Patterns of Supernumerary Segments and B Chromosomes in Dichroplus Elongates (Orthoptera)
TLDR
The patterns of chromosome variation do not agree with the geographical distribution of the populations, and the covariation of the heterochromatic forms may act as another factor that establish limits to stochastic factors, and could be involved in the non random pattern detected in D. elongarus. Expand
B-chromosomes of Trimerotropis pallidipennis ( Oedipodinae, Acrididae): new effects on chiasma conditions
TLDR
Southamerican populations of Trimerotropis pallidipennis are polymor­ phic for both pericentric inversions and supernumerary chromosomes, but three populations showed a negative correlation between total and interstitial chiasma frequencies, but it was only apparent when B-carriers were excluded from the sample. Expand
The odd-even effect in mitotically unstable B chromosomes in grasshoppers
TLDR
Some features of meiotic behaviour in known cases of polysomy and mitotically unstable Bs in grasshoppers are reviewed, in looking for possible causes for the odd-even effect. Expand
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