Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps
Half of all vertebrate species share a series of chromosome fusions that preceded the teleost genome duplication (TGD), but we do not understand the causative evolutionary mechanisms. The Robertsonian-translocation hypothesis suggests a regular fusion of each ancestral acro- or telocentric chromosom...
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ftdartmouthcoll:oai:digitalcommons.dartmouth.edu:facoa-1166 2023-07-16T03:53:23+02:00 Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps Amores, Angel Wilson, Catherine A Allard, Corey AH Dietrich, William H, III 2017-07-01T07:00:00Z text/html https://digitalcommons.dartmouth.edu/facoa/165 https://doi.org/10.1534/g3.117.040063 unknown Dartmouth Digital Commons https://digitalcommons.dartmouth.edu/facoa/165 doi:10.1534/g3.117.040063 https://doi.org/10.1534/g3.117.040063 Dartmouth Scholarship Notothenioid Antarctica Robertsonian translocation teleost genome duplication karyotype reduction Earth Sciences Environmental Sciences Physical Sciences and Mathematics text 2017 ftdartmouthcoll https://doi.org/10.1534/g3.117.040063 2023-06-28T10:42:43Z Half of all vertebrate species share a series of chromosome fusions that preceded the teleost genome duplication (TGD), but we do not understand the causative evolutionary mechanisms. The Robertsonian-translocation hypothesis suggests a regular fusion of each ancestral acro- or telocentric chromosome to just one other by centromere fusions, thus halving the karyotype. An alternative genome-stirring hypothesis posits haphazard and repeated fusions, inversions, and reciprocal and nonreciprocal translocations. To study large-scale karyotype reduction, we investigated the decrease of chromosome numbers in Antarctic notothenioid fish. Most notothenioids have 24 haploid chromosomes, but bullhead notothen (Notothenia coriiceps) has 1. To understand mechanisms, we made a RAD-tag meiotic map with approximate to 10,000 polymorphic markers. Comparative genomics aligned about a thousand orthologs of platyfish and stickleback genes along bullhead chromosomes. Results revealed that 9 of 11 bullhead chromosomes arose by fusion of just two ancestral chromosomes and two others by fusion of three ancestral chromosomes. All markers from each ancestral chromosome remained contiguous, implying no inversions across fusion borders. Karyotype comparisons support a history of: (1) Robertsonian fusions of 22 ancestral chromosomes in pairs to yield 11 fused plus two small unfused chromosomes, like N. angustata; (2) fusion of one of the remaining two ancestral chromosomes to a preexisting fused pair, giving 12 chromosomes like N. rossii; and (3) fusion of the remaining ancestral chromosome to another fused pair, giving 11 chromosomes in N. coriiceps. These results raise the question of what selective forces promoted the systematic fusion of chromosomes in pairs and the suppression of pericentric inversions in this lineage, and provide a model for chromosome fusions in stem teleosts. Text Antarc* Antarctic Antarctica Dartmouth Digital Commons (Dartmouth College) Antarctic The Antarctic G3 Genes|Genomes|Genetics 7 7 2195 2207 |
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Notothenioid Antarctica Robertsonian translocation teleost genome duplication karyotype reduction Earth Sciences Environmental Sciences Physical Sciences and Mathematics |
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Notothenioid Antarctica Robertsonian translocation teleost genome duplication karyotype reduction Earth Sciences Environmental Sciences Physical Sciences and Mathematics Amores, Angel Wilson, Catherine A Allard, Corey AH Dietrich, William H, III Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps |
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Notothenioid Antarctica Robertsonian translocation teleost genome duplication karyotype reduction Earth Sciences Environmental Sciences Physical Sciences and Mathematics |
description |
Half of all vertebrate species share a series of chromosome fusions that preceded the teleost genome duplication (TGD), but we do not understand the causative evolutionary mechanisms. The Robertsonian-translocation hypothesis suggests a regular fusion of each ancestral acro- or telocentric chromosome to just one other by centromere fusions, thus halving the karyotype. An alternative genome-stirring hypothesis posits haphazard and repeated fusions, inversions, and reciprocal and nonreciprocal translocations. To study large-scale karyotype reduction, we investigated the decrease of chromosome numbers in Antarctic notothenioid fish. Most notothenioids have 24 haploid chromosomes, but bullhead notothen (Notothenia coriiceps) has 1. To understand mechanisms, we made a RAD-tag meiotic map with approximate to 10,000 polymorphic markers. Comparative genomics aligned about a thousand orthologs of platyfish and stickleback genes along bullhead chromosomes. Results revealed that 9 of 11 bullhead chromosomes arose by fusion of just two ancestral chromosomes and two others by fusion of three ancestral chromosomes. All markers from each ancestral chromosome remained contiguous, implying no inversions across fusion borders. Karyotype comparisons support a history of: (1) Robertsonian fusions of 22 ancestral chromosomes in pairs to yield 11 fused plus two small unfused chromosomes, like N. angustata; (2) fusion of one of the remaining two ancestral chromosomes to a preexisting fused pair, giving 12 chromosomes like N. rossii; and (3) fusion of the remaining ancestral chromosome to another fused pair, giving 11 chromosomes in N. coriiceps. These results raise the question of what selective forces promoted the systematic fusion of chromosomes in pairs and the suppression of pericentric inversions in this lineage, and provide a model for chromosome fusions in stem teleosts. |
format |
Text |
author |
Amores, Angel Wilson, Catherine A Allard, Corey AH Dietrich, William H, III |
author_facet |
Amores, Angel Wilson, Catherine A Allard, Corey AH Dietrich, William H, III |
author_sort |
Amores, Angel |
title |
Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps |
title_short |
Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps |
title_full |
Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps |
title_fullStr |
Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps |
title_full_unstemmed |
Cold Fusion: Massive Karyotype Evolution in the Antarctic Bullhead Notothen Notothenia coriiceps |
title_sort |
cold fusion: massive karyotype evolution in the antarctic bullhead notothen notothenia coriiceps |
publisher |
Dartmouth Digital Commons |
publishDate |
2017 |
url |
https://digitalcommons.dartmouth.edu/facoa/165 https://doi.org/10.1534/g3.117.040063 |
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Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
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Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
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Dartmouth Scholarship |
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https://digitalcommons.dartmouth.edu/facoa/165 doi:10.1534/g3.117.040063 https://doi.org/10.1534/g3.117.040063 |
op_doi |
https://doi.org/10.1534/g3.117.040063 |
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G3 Genes|Genomes|Genetics |
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2195 |
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