Non-random segregation during anaphase II in an individual of Arcyptera tornosi (Bol.) (Orthoptera) heterozygous for three supernumerary heterochromatic segments

López‐Fernández, Carmen; Rufas, Julio S.; Gosálvez, Jaime

doi:10.1007/bf00121455

Cited by 6 publications

(2 citation statements)

References 10 publications

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“…However, some examples of non Mendelian inheritance of supernumerary segments have been reported. (LOPEZ-LEON et al 1992;LOPEZ-FERNANDEZ et al 1982;WILBY and PARKER 1988).…”

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Supernumerary heterochromatin, chiasma conditions and abnormal sperm formation inDichroplus elongatus(Orthoptera): intra and interpopulation analysis

et al. 1994

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SUMMARY -Parallel polymorphisms for B chromosome and supernumerary segments on M,, s. and S,. pairs have been detected in two Argentinian populations of Dichroplus elongatus, Raco (RA) and Tafi Viejo (TV) (Tucuman Province). All these polymorphisms seem to be temporally stable. In all samples of TV, it was observed a tendency towards an excess of the B + SS, class. SS, produces a total restriction of chiasma formation in proximal position in the involved pair in heterozygous and homozygous males. In TV a consistent dose effect of B chromosome on interstitial chiasma (X;) frequency was detected in males. The X; frequency vs. number of supernumeraries plot fits to a linear regression. In both populations, the individuals with B's showed a significant increase in macro-and microspermatid production. This effect is more marked at RA. 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 cytokinesis blocking. However, spermatids with 3 to 5C contents in B carriers were also detected showing that other mechanism (i.e. cell fusion) may also account to explain the effects of B's on abnormal sperm formation.

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“…However, some examples of non Mendelian inheritance of supernumerary segments have been reported. (LOPEZ-LEON et al 1992;LOPEZ-FERNANDEZ et al 1982;WILBY and PARKER 1988).…”

mentioning

confidence: 99%

Supernumerary heterochromatin, chiasma conditions and abnormal sperm formation inDichroplus elongatus(Orthoptera): intra and interpopulation analysis

et al. 1994

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“…Furthermore, nonrandom segregation of the chromosomes (chromatids) with the heterochromatic short arms could lead to homozygosity for the presence or absence of the short arms in the progeny cells. Nonrandom segregation of chromosomes carrying extra heterochromatin has been observed frequently in the heterozygous condition (e.g., Lopez-Fernandez et al, 1982;Agulnik et al, 1990; and references therein).…”

Section: Resultsmentioning

confidence: 99%

Increases and decreases of whole-arm heterochromatin in specific chromosomes: an extraordinary situation in hybrids of the <i>Mus terricolor</i> complex

Sharma

Bardhan²,

Bahadur³

2002

Cytogenet Genome Res

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The three chromosomal species of Mus terricolor display fixed variations in the short-arm heterochromatin of autosomes 1, 3, and 6. Some laboratory-generated hybrids among the chromosomal species show an unusual increase or decrease in the extent of whole-arm heterochromatin, instead of the expected heterozygosity for the heterochromatic short arms. The whole-arm increase/decrease tends to favor homozygosity for the presence or absence of the heterochromatic short arms. Interestingly, this increase/decrease conforms with the karyotypes of the parental chromosomal species. Although rapid karyotypic changes have been reported in other plant and animal hybrids, the situation observed in the M. terricolor hybrids is unique. The changes are stable and could be a product of the unusual chromosomal organization of recombinogenic telomeric sequences in this species complex. The altered karyological constitution is constant in both somatic and germ cells of each hybrid, suggesting that the changes occurred early in their development. The high frequency and nonrandom recurrence of similar changes in different hybrids seem to reflect a mechanism that might have been instrumental in the fixation of these chromosomal variations in a stable homozygous condition in natural populations.

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Effects of supernumerary heterochromatin on chiasma condition in two species of Acrididae (Orthoptera)

Remis

1989

Genetica

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Amblytropidia australis and Dichroplus elongatus were found to be polymorphic for supernumerary heterochromatin. In both, basic karyotypes are 2n = 22 + XO in males.Mitotically unstable extra chromosomes were detected in a population of A. australis. The Bs are telocentric and their number varies from O to 2 within individuals. Mean frequencies of interstitial and total chiasmata at diplotene were compared between individuals with and without Bs. The mean frequency of interstitial chiasmata increases with the number of Bs per cell.A supernumerary terminal segment in S ~0 pair was observed in a heterozygous condition in several individuals of D. elongatus. The localization and frequency of chiasmata at diplotene were studied. The segment has an intrachromosomal effect since it modifies the location of chiasmata in the bivalent involved.

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Non-random segregation during anaphase II in an individual of Arcyptera tornosi (Bol.) (Orthoptera) heterozygous for three supernumerary heterochromatic segments

Cited by 6 publications

References 10 publications

Supernumerary heterochromatin, chiasma conditions and abnormal sperm formation inDichroplus elongatus(Orthoptera): intra and interpopulation analysis

Supernumerary heterochromatin, chiasma conditions and abnormal sperm formation inDichroplus elongatus(Orthoptera): intra and interpopulation analysis

Increases and decreases of whole-arm heterochromatin in specific chromosomes: an extraordinary situation in hybrids of the <i>Mus terricolor</i> complex

Effects of supernumerary heterochromatin on chiasma condition in two species of Acrididae (Orthoptera)

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