Consequences of recombination for the evolution of the mating type locus in Chlamydomonas reinhardtii
© 2019 The Authors. New Phytologist © 2019 New Phytologist Trust.
| Veröffentlicht in: | The New phytologist. - 1979. - 224(2019), 3 vom: 21. Nov., Seite 1339-1348 |
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| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2019
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| Zugriff auf das übergeordnete Werk: | The New phytologist |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Chlamydomonas gene conversion mating-type loci organelle inheritance sex chromosome degeneration |
| Zusammenfassung: | © 2019 The Authors. New Phytologist © 2019 New Phytologist Trust. Recombination suppression in sex chromosomes and mating type loci can lead to degeneration as a result of reduced selection efficacy and Muller's ratchet effects. However, genetic exchange in the form of noncrossover gene conversions may still take place within crossover-suppressed regions. Recent work has found evidence that gene conversion may explain the low degrees of allelic differentiation in the dimorphic mating-type locus (MT) of the isogamous alga Chlamydomonas reinhardtii. However, no one has tested whether gene conversion is sufficient to avoid the degeneration of functional sequence within MT. Here, we calculate degree of linkage disequilibrium (LD) across MT as a proxy for recombination rate and investigate its relationship to patterns of population genetic variation and the efficacy of selection in the region. We find that degree of LD predicts selection efficacy across MT, and that purifying selection is stronger in shared genes than in MT-limited genes to the point of being equivalent to that of autosomal genes. We argue that while crossover suppression is needed in the mating-type loci of many isogamous systems, these loci are less likely to experience selection to differentiate further. Thus, recombination can act in these regions and prevent degeneration caused by Hill-Robertson effects |
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| Beschreibung: | Date Completed 22.07.2020 Date Revised 30.09.2020 published: Print-Electronic GENBANK: GU814015.1 Citation Status MEDLINE |
| ISSN: | 1469-8137 |
| DOI: | 10.1111/nph.16003 |