Centromere diversity and its evolutionary impacts on plant karyotypes and plant reproduction

New Phytologist, Год журнала: 2025, Номер 245(5), С. 1879 - 1886

Опубликована: Янв. 6, 2025

Summary Karyotype changes are a formidable evolutionary force by directly impacting cross‐incompatibility, gene dosage, genetic linkage, chromosome segregation, and meiotic recombination landscape. These often arise spontaneously commonly detected within plant lineages, even between closely related accessions. One element that can influence drastic karyotype after only one (or few) generations is the alteration of centromere position, number, distribution, or its strength. Here, we briefly explore how these different configurations result in rearrangements, reproduction recombination.

Язык: Английский

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Evolution of Hybrid Inviability Associated With Chromosome Fusions

Molecular Ecology, Год журнала: 2025, Номер unknown

Опубликована: Фев. 3, 2025

ABSTRACT Chromosomal rearrangements, such as inversions, have received considerable attention in the speciation literature due to their hampering effects on recombination. Less is known about how other chromosome fissions and fusions, can affect evolution of reproductive isolation. Here, we use crosses between populations wood white butterfly ( Leptidea sinapis ) with different karyotypes identify genomic regions associated hybrid inviability. We map inviability candidate loci by contrasting allele frequencies F 2 hybrids that survived until adult stage individuals same cohort succumbed incompatibilities. Hybrid high genetic differentiation parental populations, reduced recombination rates, are enriched near fusions. By analysing sequencing coverage, exclude aneuploidies a direct link Instead, our results point an indirect relationship possibly related fused chromosomes. Thus, postzygotic isolation chromosomal providing crucial empirical evidence for idea number differences taxa contribute speciation.

Язык: Английский

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Chromosomal fusions and large-scale inversions are key features for adaptation in Arctic codfish species

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Июнь 28, 2024

Abstract The evolutionary impact of structural variants, such as chromosomal inversions, is well documented, especially for their role in local adaptation high gene flow systems. However, the other genomic rearrangements like fusions, fissions, and translocations still relatively unexplored. Here we present six chromosome-level Gadid reference genomes non-migratory Atlantic cod ( Gadus morhua ) i.e., Norwegian coastal (NCC), haddock (Melanogrammus aeglefinus), burbot Lota lota ), European hake Merluccius merluccius two keystone Arctic codfishes: polar Boreogadus saida Arctogadus glacialis ). Within a comparative genomics framework, uncovered several lineage-specific resulting reduced number chromosomes compared to ancestral state cold-water adapted codfishes. identified fusions were not homologous, indicating that they originate from independent events. Additionally, partly overlapping inversions between species detected. Using smaller population dataset, degree conservation some (including breakpoint regions), suggesting these regions are under selection, potentially importance. With use genome assemblies, demonstrate how large reorganizations likely play important roles speciation processes thus, particular freezing environmental conditions. Moreover, observe massive rearrangement events can take place across short time scales.

Язык: Английский

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Meiotic drive against chromosome fusions in butterfly hybrids

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Фев. 7, 2024

Abstract Species frequently differ in karyotype, but heterokaryotypic individuals may suffer from reduced fitness. Chromosomal rearrangements like fissions and fusions can thus serve as a mechanism for speciation between incipient lineages their evolution poses paradox. How does underdominant evolve? One solution is the fixation of chromosomal through genetic drift. However, this requires small isolated populations. Fixation more likely if novel rearrangement favored by transmission bias, such meiotic drive. Here, we investigate ratio distortion hybrids two wood white ( Leptidea sinapis ) butterfly populations with extensive karyotype differences. Using data different crossing experiments, uncover bias favoring fused state at chromosome unknown polarization one experiment unfused derived both experiments. The latter result support scenario where fix despite counteracting effects This means that drive not only promote runaway number speciation, also be conservative force acting against karyotypic change reproductive isolation. Based on our results, suggest mechanistic model why opposed discuss factors contributing to Lepidoptera.

Язык: Английский

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Annelid comparative genomics and the evolution of massive lineage-specific genome rearrangement in bilaterians

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Май 18, 2024

Abstract The organization of genomes into chromosomes is critical for processes such as genetic recombination, environmental adaptation, and speciation. All animals with bilateral symmetry inherited a genome structure from their last common ancestor that has been highly conserved in some taxa but seemingly unconstrained others. However, the evolutionary forces driving these differences by which they emerge have remained largely uncharacterized. Here we analyze across phylum Annelida using 23 chromosome-level annelid genomes. We find while most annelids maintained bilaterian structure, group containing leeches earthworms possesses completely scrambled develop rearrangement index to quantify extent evolution show rearranged any currently sampled bilaterian. further can be classified two distinct categories—high low rearrangement—largely influenced presence or absence, respectively, chromosome fission events. Our findings demonstrate animal variable within reveal occur both gradual, stepwise fashion rapid, all-encompassing changes over short timescales.

Язык: Английский

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GC content across insect genomes: phylogenetic patterns, causes and consequences

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Сен. 12, 2023

Abstract The proportions of A:T and G:C nucleotide pairs are often unequal can vary greatly between animal species along chromosomes. causes consequences this variation incompletely understood. recent release high-quality genome sequences from the Darwin Tree Life other large-scale projects provides an opportunity for GC heterogeneity to be compared across a large number insect species. Here we analyse content chromosomes, within protein-coding genes codons, 150 four holometabolous orders: Coleoptera, Diptera, Hymenoptera, Lepidoptera. We find that have higher than average, Lepidoptera generally three orders examined. is in small chromosomes most species, but pattern less consistent orders. also increases towards subtelomeric regions Coleoptera and, strikingly, Two Bombylius major B. discolo r, very atypical genomes with ubiquitous increase AT content, especially at third codon positions. Despite dramatic AT-biased usage, no evidence has driven divergent protein evolution. argue landscape Lepidoptera, Hymenoptera influenced by GC-biased gene conversion, strongest some outlier taxa affected drastically counteracting processes.

Язык: Английский

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Evolution of hybrid inviability associated with chromosome fusions

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Дек. 1, 2023

Abstract Chromosomal rearrangements, such as inversions, have received considerable attention in the speciation literature due to their hampering effects on recombination. However, less is known about how other chromosome fissions and fusions, can affect evolution of reproductive isolation. Here, we used crosses between populations wood white butterfly ( Leptidea sinapis ) with different karyotypes identify genomic regions associated hybrid inviability. By contrasting allele frequencies F 2 hybrids that survived until adult stage individuals same cohort succumbed incompatibilities, show candidate loci for inviability mainly are situated fast-evolving reduced recombination rates, especially where fusions occurred. Our results extensive variation numbers observed across tree life be involved by being hotspots early postzygotic

Язык: Английский

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Sex-specific recombination landscape in a species with holocentric chromosomes

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Апрель 17, 2024

Abstract The rate and chromosomal positioning of meiotic recombination significantly affects the distribution genetic diversity in eukaryotic genomes. Many studies have revealed sex-specific patterns, with male typically biased toward chromosome ends, while female is more evenly distributed along chromosomes, or concentrated near center. It has been proposed that such pattern females may counteract drive caused by selfish elements centromeres should not occur species devoid clearly defined centromeres, but evidence for latter scarce. Here, we constructed a map holocentric bulb mite ( Rhizoglyphus robini ), sexual selection model alternative reproductive phenotypes. We found similar landscape both males females, consistent increased rates towards higher than males. A region on 7, carrying high density markers associated expression phenotypes, was among several regions particularly low rate. detected positive correlation between repeat (highest at ends), negative gene (peaking centers). Our results are hypothesis suggest evolution closely linked to features.

Язык: Английский

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Chromosomal fusion drives sex chromosome evolution in treehoppers despite long-term X chromosome conservation

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2024, Номер unknown

Опубликована: Июль 15, 2024

Abstract Sex chromosomes follow distinct evolutionary trajectories compared to the rest of genome. In many cases, sex (X and Y, or Z W) significantly differentiate from one another resulting in heteromorphic chromosome systems. Such systems are thought act as an trap that prevents subsequent turnover system. For old, degenerated which is unlikely, chromosomal fusion with autosome may be way can ‘refresh’ their sequence content. We investigated these dynamics using treehoppers (hemipteran insects family Membracidae), ancestrally have XX/X0 chromosomes. assembled first chromosome-level treehopper genome Umbonia crassicornis employed comparative genomic analyses 12 additional species analyze X variation across different timescales. find largely conserved, exception being X-autosome Calloconophora caliginosa . also compare ancestral other Auchenorrhyncha (the clade containing treehoppers, leafhoppers, spittlebugs, cicadas, planthoppers), revealing conservation more than 300 million years. These findings shed light on evolution role rearrangements evolution. Significance The forces underlying stability versus been challenging disentangle. present evidence long-term within – among hemipteran insects. A key neo-XX/XY via fusion. chromosome-autosome fusions play important otherwise ‘trapped’ (i.e., old degenerated)

Язык: Английский

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Genomics of Neotropical biodiversity indicators: two butterfly radiations with rampant chromosomal rearrangements and hybridisation

Опубликована: Июль 10, 2024

Abstract A major question in evolutionary biology is what drives the diversification of lineages. Rapid, recent radiations are ideal systems for addressing how new species arise because they still show key morphological and ecological adaptations associated with speciation. While most studied have evolved an insular environment, less research has been carried out on continental complex interactions. Melinaea Mechanitis butterflies (Nymphalidae: Ithomiini) rapidly radiated Neotropics. They classical models Amazonian biogeography colour pattern mimicry proposed as biodiversity indicators. We generated reference genomes five each genus, whole-genome resequencing data subspecies covering a wide geographic range to assess phylogeographic relationships, patterns hybridisation chromosomal rearrangements. Our help resolve classification these taxonomically challenging reveal very high rates. find rampant evidence historical putative hybrid both radiations, which may facilitated their rapid diversification. Moreover, dozens fusions fissions were identified between congeneric species, even some within species. conclude that interactions geography, rearrangements contributed two highly diverse Neotropical region. suggest be spurred by repeated periods isolation during Pleistocene climate oscillations, combined lineage-specific accumulation incompatibilities allopatric phases, followed secondary contact gene exchange. Significance Statement Understanding factors contributing speciation aim biology. Here we focus butterflies. genomic broad taxonomic coverage rearrangements, likely study highlights use groups elucidate drivers radiations. hotspots barcoding insufficient characterise richness due flow The implications introgression karyotype diversity delimitation important consider monitoring management vulnerable habitats. Classification: Biological Sciences - Evolution

Язык: Английский

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