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Updated: Aug 4, 2026
22:27
Hi-C: A Method to Study the Three-dimensional Architecture of Genomes.
Published on: May 7, 2010
Quantitative DNA variation and chromosome homology
Symposia of the Society for Experimental Biology
|January 1, 1984
Summary
Massive DNA changes during speciation don't hinder homologous chromosome pairing. Genotypes control preventing chiasma formation between non-homologous chromosomes with shared DNA sequences.
Area of Science:
- Genetics
- Evolutionary Biology
- Molecular Biology
Background:
- Speciation and divergence in plants and animals often involve significant alterations in nuclear DNA content.
- These DNA changes arise from the amplification or repetition of base sequences, leading to variations in chromosome size and structure between species.
Purpose of the Study:
- To investigate the impact of large-scale chromosome structural changes on homologous chromosome pairing and chiasma formation during meiosis.
- To explore the genetic mechanisms that prevent chiasma formation between non-homologous chromosomes sharing similar DNA sequences.
Main Methods:
- Analysis of chromosome pairing and chiasma formation in hybrids between species with differing nuclear DNA amounts.
- Examination of evidence for genotypic control over pairing and chiasma formation in meiosis.
Main Results:
- Homoeologous chromosomes pair effectively and form chiasmata even with substantial differences in DNA content (up to ~60%).
- Very large DNA differences (≥60%) can impair pachytene pairing and chiasma formation.
- Repetitive DNA sequences, widespread across non-homologous chromosomes, do not inherently prevent pairing.
Conclusions:
- Large-scale chromosome structural changes due to DNA sequence repetition have minimal impact on homologous chromosome homology and meiotic pairing.
- Genotype plays a crucial role in preventing chiasma formation between non-homologous chromosomes.
- This prevention is achieved by suppressing either pairing during zygotene/pachytene or chiasma formation post-pairing.
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