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Effects of Inversions on Within- and Between-Species Recombination and Divergence

Chromosomal inversions disrupt recombination in heterozygotes by both reducing crossing-over within inverted regions and increasing it elsewhere in the genome. The reduction of recombination in inverted regions facilitates the maintenance of hybridizing species, as outlined by various models of chro...

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Autores principales: Stevison, Laurie S., Hoehn, Kenneth B., Noor, Mohamed A. F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3171675/
https://www.ncbi.nlm.nih.gov/pubmed/21828374
http://dx.doi.org/10.1093/gbe/evr081
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author Stevison, Laurie S.
Hoehn, Kenneth B.
Noor, Mohamed A. F.
author_facet Stevison, Laurie S.
Hoehn, Kenneth B.
Noor, Mohamed A. F.
author_sort Stevison, Laurie S.
collection PubMed
description Chromosomal inversions disrupt recombination in heterozygotes by both reducing crossing-over within inverted regions and increasing it elsewhere in the genome. The reduction of recombination in inverted regions facilitates the maintenance of hybridizing species, as outlined by various models of chromosomal speciation. We present a comprehensive comparison of the effects of inversions on recombination rates and on nucleotide divergence. Within an inversion differentiating Drosophila pseudoobscura and Drosophila persimilis, we detected one double recombinant among 9,739 progeny from F(1) hybrids screened, consistent with published double-crossover frequencies observed within species. Despite similar rates of exchange within and between species, we found no sequence-based evidence of ongoing gene exchange between species within this inversion, but significant exchange was inferred within species. We also observed greater differentiation at regions near inversion breakpoints between species versus within species. Moreover, we observed strong “interchromosomal effect” (higher recombination in inversion heterozygotes between species) with up to 9-fold higher recombination rates along collinear segments of chromosome two in hybrids. Further, we observed that regions most susceptible to changes in recombination rates corresponded to regions with lower recombination rates in homokaryotypes. Finally, we showed that interspecies nucleotide divergence is lower in regions with greater increases in recombination rate, potentially resulting from greater interspecies exchange. Overall, we have identified several similarities and differences between inversions segregating within versus between species in their effects on recombination and divergence. We conclude that these differences are most likely due to lower frequency of heterokaryotypes and to fitness consequences from the accumulation of various incompatibilities between species. Additionally, we have identified possible effects of inversions on interspecies gene exchange that had not been considered previously.
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spelling pubmed-31716752011-09-13 Effects of Inversions on Within- and Between-Species Recombination and Divergence Stevison, Laurie S. Hoehn, Kenneth B. Noor, Mohamed A. F. Genome Biol Evol Research Articles Chromosomal inversions disrupt recombination in heterozygotes by both reducing crossing-over within inverted regions and increasing it elsewhere in the genome. The reduction of recombination in inverted regions facilitates the maintenance of hybridizing species, as outlined by various models of chromosomal speciation. We present a comprehensive comparison of the effects of inversions on recombination rates and on nucleotide divergence. Within an inversion differentiating Drosophila pseudoobscura and Drosophila persimilis, we detected one double recombinant among 9,739 progeny from F(1) hybrids screened, consistent with published double-crossover frequencies observed within species. Despite similar rates of exchange within and between species, we found no sequence-based evidence of ongoing gene exchange between species within this inversion, but significant exchange was inferred within species. We also observed greater differentiation at regions near inversion breakpoints between species versus within species. Moreover, we observed strong “interchromosomal effect” (higher recombination in inversion heterozygotes between species) with up to 9-fold higher recombination rates along collinear segments of chromosome two in hybrids. Further, we observed that regions most susceptible to changes in recombination rates corresponded to regions with lower recombination rates in homokaryotypes. Finally, we showed that interspecies nucleotide divergence is lower in regions with greater increases in recombination rate, potentially resulting from greater interspecies exchange. Overall, we have identified several similarities and differences between inversions segregating within versus between species in their effects on recombination and divergence. We conclude that these differences are most likely due to lower frequency of heterokaryotypes and to fitness consequences from the accumulation of various incompatibilities between species. Additionally, we have identified possible effects of inversions on interspecies gene exchange that had not been considered previously. Oxford University Press 2011-08-09 /pmc/articles/PMC3171675/ /pubmed/21828374 http://dx.doi.org/10.1093/gbe/evr081 Text en © The Author(s) 2011. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Articles
Stevison, Laurie S.
Hoehn, Kenneth B.
Noor, Mohamed A. F.
Effects of Inversions on Within- and Between-Species Recombination and Divergence
title Effects of Inversions on Within- and Between-Species Recombination and Divergence
title_full Effects of Inversions on Within- and Between-Species Recombination and Divergence
title_fullStr Effects of Inversions on Within- and Between-Species Recombination and Divergence
title_full_unstemmed Effects of Inversions on Within- and Between-Species Recombination and Divergence
title_short Effects of Inversions on Within- and Between-Species Recombination and Divergence
title_sort effects of inversions on within- and between-species recombination and divergence
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3171675/
https://www.ncbi.nlm.nih.gov/pubmed/21828374
http://dx.doi.org/10.1093/gbe/evr081
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