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Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma

Genome evolution is driven by a complex interplay of factors, including selection, recombination, and introgression. The regions determining sexual identity are particularly dynamic parts of eukaryotic genomes that are prone to molecular degeneration associated with suppressed recombination. In the...

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Autores principales: Corcoran, Pádraic, Anderson, Jennifer L., Jacobson, David J., Sun, Yu, Ni, Peixiang, Lascoux, Martin, Johannesson, Hanna
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cold Spring Harbor Laboratory Press 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817772/
https://www.ncbi.nlm.nih.gov/pubmed/26893460
http://dx.doi.org/10.1101/gr.197244.115
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author Corcoran, Pádraic
Anderson, Jennifer L.
Jacobson, David J.
Sun, Yu
Ni, Peixiang
Lascoux, Martin
Johannesson, Hanna
author_facet Corcoran, Pádraic
Anderson, Jennifer L.
Jacobson, David J.
Sun, Yu
Ni, Peixiang
Lascoux, Martin
Johannesson, Hanna
author_sort Corcoran, Pádraic
collection PubMed
description Genome evolution is driven by a complex interplay of factors, including selection, recombination, and introgression. The regions determining sexual identity are particularly dynamic parts of eukaryotic genomes that are prone to molecular degeneration associated with suppressed recombination. In the fungus Neurospora tetrasperma, it has been proposed that this molecular degeneration is counteracted by the introgression of nondegenerated DNA from closely related species. In this study, we used comparative and population genomic analyses of 92 genomes from eight phylogenetically and reproductively isolated lineages of N. tetrasperma, and its three closest relatives, to investigate the factors shaping the evolutionary history of the genomes. We found that suppressed recombination extends across at least 6 Mbp (∼63%) of the mating-type (mat) chromosome in N. tetrasperma and is associated with decreased genetic diversity, which is likely the result primarily of selection at linked sites. Furthermore, analyses of molecular evolution revealed an increased mutational load in this region, relative to recombining regions. However, comparative genomic and phylogenetic analyses indicate that the mat chromosomes are temporarily regenerated via introgression from sister species; six of eight lineages show introgression into one of their mat chromosomes, with multiple Neurospora species acting as donors. The introgressed tracts have been fixed within lineages, suggesting that they confer an adaptive advantage in natural populations, and our analyses support the presence of selective sweeps in at least one lineage. Thus, these data strongly support the previously hypothesized role of introgression as a mechanism for the maintenance of mating-type determining chromosomal regions.
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spelling pubmed-48177722016-04-22 Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma Corcoran, Pádraic Anderson, Jennifer L. Jacobson, David J. Sun, Yu Ni, Peixiang Lascoux, Martin Johannesson, Hanna Genome Res Research Genome evolution is driven by a complex interplay of factors, including selection, recombination, and introgression. The regions determining sexual identity are particularly dynamic parts of eukaryotic genomes that are prone to molecular degeneration associated with suppressed recombination. In the fungus Neurospora tetrasperma, it has been proposed that this molecular degeneration is counteracted by the introgression of nondegenerated DNA from closely related species. In this study, we used comparative and population genomic analyses of 92 genomes from eight phylogenetically and reproductively isolated lineages of N. tetrasperma, and its three closest relatives, to investigate the factors shaping the evolutionary history of the genomes. We found that suppressed recombination extends across at least 6 Mbp (∼63%) of the mating-type (mat) chromosome in N. tetrasperma and is associated with decreased genetic diversity, which is likely the result primarily of selection at linked sites. Furthermore, analyses of molecular evolution revealed an increased mutational load in this region, relative to recombining regions. However, comparative genomic and phylogenetic analyses indicate that the mat chromosomes are temporarily regenerated via introgression from sister species; six of eight lineages show introgression into one of their mat chromosomes, with multiple Neurospora species acting as donors. The introgressed tracts have been fixed within lineages, suggesting that they confer an adaptive advantage in natural populations, and our analyses support the presence of selective sweeps in at least one lineage. Thus, these data strongly support the previously hypothesized role of introgression as a mechanism for the maintenance of mating-type determining chromosomal regions. Cold Spring Harbor Laboratory Press 2016-04 /pmc/articles/PMC4817772/ /pubmed/26893460 http://dx.doi.org/10.1101/gr.197244.115 Text en © 2016 Corcoran et al.; Published by Cold Spring Harbor Laboratory Press http://creativecommons.org/licenses/by/4.0/ This article, published in Genome Research, is available under a Creative Commons License (Attribution 4.0 International), as described at http://creativecommons.org/licenses/by/4.0/.
spellingShingle Research
Corcoran, Pádraic
Anderson, Jennifer L.
Jacobson, David J.
Sun, Yu
Ni, Peixiang
Lascoux, Martin
Johannesson, Hanna
Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma
title Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma
title_full Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma
title_fullStr Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma
title_full_unstemmed Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma
title_short Introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus Neurospora tetrasperma
title_sort introgression maintains the genetic integrity of the mating-type determining chromosome of the fungus neurospora tetrasperma
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817772/
https://www.ncbi.nlm.nih.gov/pubmed/26893460
http://dx.doi.org/10.1101/gr.197244.115
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