Finding the Correct Partner: The Meiotic Courtship
Homologous chromosomes are usually separated at the entrance of meiosis; how they become paired is one of the outstanding mysteries of the meiotic process. Reduction of spacing between homologues makes possible the occurrence of chromosomal interactions leading to homology detection and the formatio...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2012-01-01
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| Series: | Scientifica |
| Online Access: | http://dx.doi.org/10.6064/2012/509073 |
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| Summary: | Homologous chromosomes are usually separated at the entrance of meiosis;
how they become paired is one of the outstanding mysteries of the meiotic
process. Reduction of spacing between homologues makes possible the
occurrence of chromosomal interactions leading to homology detection and the
formation of bivalents. In many organisms, telomere-led chromosome
movements are generated that bring homologues together. Additional
movements produced by chromatin conformational changes at early meiosis
may also facilitate homologous contacts. Organisms used in the study of
meiosis show a surprising variety of strategies for homology detection. In
dipterans, homologous chromosomes remain paired throughout most of
development. Pairing seems to arise as a balance between promoter and
suppressor pairing genes. Some fungi, plants and animals, use mechanisms
based on recombinational interactions. Other mechanisms leading to homology
search are recombination-independent and require specialized pairing sites. In
the worm Caenorhabditis elegans, each chromosome carries a pairing center
consisting of a chromosome-specific DNA-protein complex, and in the fission
yeast Schizosaccharomyces pombe, the sme2 locus encodes a meiosis-specific
non-coding RNA that mediates on homologous recognition. In addition,
mismatch correction plays a relevant role, especially in polyploids, which
evolved genetic systems that suppress pairing between non-homologous
related (homoeologus) chromosomes. |
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| ISSN: | 2090-908X |