Holocentric chromosomes in meiosis. II. The modes of orientation and segregation of a trivalent

  title={Holocentric chromosomes in meiosis. II. The modes of orientation and segregation of a trivalent},
  author={Seppo Nokkala and Valentina G. Kuznetsova and Anna Maryańska‐Nadachowska and Christina Nokkala},
  journal={Chromosome Research},
The modes of orientation and segregation of the sex chromosome trivalent X1X2Y in male meiosis of Cacopsylla mali (Psylloidea, Homoptera) were analysed. Males with an X1X2Y sex chromosome system coexist with males displaying a neo-XY system in populations of this species. The fusion chromosome resulting in the formation of a trivalent in meiosis originates from the fusion of an autosome with the neo-Y chromosome. In the majority of metaphase I cells (92.4%) the X1X2Y trivalent showed co… 

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The present observations suggest that the histone modifications analyzed here evolved in Heteroptera as markers for asynaptic and achiasmatic sex chromosomes during meiosis to allow the distinction from the chiasmatic autosomal chromosomes.

Versatility of multivalent orientation, inverted meiosis, and rescued fitness in holocentric chromosomal hybrids

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The fact that this rearrangement has been found in a natural population of T. infestans and that it shows a regular meiotic behaviour seems to support the suggested hypothesis of karyotype evolution in Heteroptera.

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  • J. Loidl
  • Biology
    Annual review of genetics
  • 2016
It is confirmed that meiosis originated in the common ancestor of all eukaryotes and suggests that primordial meiosis may have had many characteristics in common with conventional extant meiosis, however, it is possible that the synaptonemal complex and the delicate crossover control related to its presence were later acquisitions.

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The elimination of the cells carrying bivalents with more than two chiasmata creates a strong selection against the formation of more than one chiasma loops in holocentric bivalENTs.

Mitotic and meiotic chromosomes in Somatochlora metallica (Cordulidae, Odonata). The absence of localized centromeres and inverted meiosis.

Meiosis in these male dragonflies is thus pre-reductional or conventional, not post-red reductional or inverted, as has been previously proposed, and the kinetic behaviour of the chromosomes both in mitosis and meiosis showed that they were holocentric.

Inverted meiosis and meiotic drive in mealybugs

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The absence of chiasma terminalization and inverted meiosis in males and females of Myrmus miriformis Fn. (Corizidae, Heteroptera)

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Chromosome rearrangements in Belostoma plebejum (Stål) (Belostomatidae, Heteroptera)

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Cytogenetics of Holokinetic Chromosomes and Inverted Meiosis: Keys to the Evolutionary Success of Mites, with Generalizations on Eukaryotes

The evolution of sexual reproduction has seen a recent and major resurgence as a topic of interest and theorists have learned that the many strange genetic systems and breeding biologies of plants, animals and protists blur the distinction between “sexual” and “asexual”.

Holding chromatids together to ensure they go their separate ways

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    BioEssays : news and reviews in molecular, cellular and developmental biology
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Chromosome cohesion and segregation in mitosis and meiosis.

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  • 2001

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