Related Experiment Video
Updated: Jun 22, 2026

Chromatin Spread Preparations for the Analysis of Mouse Oocyte Progression from Prophase to Metaphase II
Published on: February 26, 2018
[C-heterochromatin during synapsis and recombination in grey cockroach Nauphoeta cinerea spermatogenesis]
Abstract:
The behaviour of large distal C-heterochromatic blocks in spermatogenesis of grey cockroach Nauphoeta cinerea was investigated by light and electron microscopy. Heterochromatic blocks of some autosomes are involved into nonhomologous association with formation of chromocenter in early meiotic prophase I. Fluorescent in situ hybridization with ribosomal DNA-probe revealed the signal on only two pairs of middle chromosomes, which did not participate in the chromocenter formation, therefore appearance of ectopic contacts was not caused by the nucleolus formation. The analysis showed that heterochromatin in the chromocenter was eliminated spatially and functionally from main meiotic events. Heterochromatin does not participate in the bouquet formation, initiation of homologous pairing, and recombination events. Heterochromatic polymorphism results in asymmetric synaptonemal complexes with different degree of synaptic adjustment. Meiotic axis of sex univalent (XO -- sex male determination) is split in different regions irrespective of heterochromatin localization.
Related Concept Videos
Heterochromatin
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Heterochromatin
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Crossing Over
Crossing Over
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
Meiosis I
Meiosis I
Prophase I is the most extended and complex step of meiosis I characterized by synapsis, chromosome pairing, and recombination of the homologous chromosomes. This process is facilitated by a proteinaceous structure called the...

