Evolution of Hybrid Inviability Associated With Chromosome Fusions

Molecular Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 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.

Language: Английский

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The Role of Meiotic Drive in Chromosome Number Disparity Between Heterosporous and Homosporous Plants

Molecular Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: April 7, 2025

ABSTRACT In vascular plants, heterosporous lineages typically have fewer chromosomes than homosporous lineages. The underlying mechanism causing this disparity has been debated for over half a century. Although reproductive mode identified as critical to these patterns, the symmetry of meiosis during sporogenesis overlooked potential cause difference in chromosome numbers. most megasporogenesis is asymmetric, meaning one four meiotic products survives become egg. Comparatively, symmetric and all survive. important because asymmetric enables drive associated genomic changes, while cannot lead drive. Meiotic deviation from Mendelian inheritance where genetic elements are preferentially inherited by surviving egg cell, can profoundly impact (and genome) size, structure, number. Here we review how impacts number evolution lack plants their genomes, explore future approaches understand role on across land plants.

Language: Английский

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Cytogenetics of insects in the era of chromosome-level genome assemblies

Vavilov Journal of Genetics and Breeding, Journal Year: 2025, Volume and Issue: 29(2), P. 230 - 237

Published: April 10, 2025

Over the past few years, a revolution has occurred in cytogenetics, driven by emergence and spread of methods for obtaining high-quality chromosome-level genome assemblies. In fact, this led to new tool studying chromosomes chromosomal rearrangements, is thousands times more powerful than light microscopy. This revolutionized cytogenetics many groups insects which previously karyotype information, if available at all, was limited chromosome number. Even impressive are achievements genomic approach general patterns organization evolution insects. Thus, it been shown that rapid transformations numbers, often found order Lepidoptera, most carried out parsimonious way, as result simple fusions fissions chromosomes. It established these not random occur independently different phylogenetic lineages due reuse same ancestral breakpoints. tendency correlated with presence so-called interstitial telomeres, i.e. telomere-like structures located ends chromosomes, but inside them. revealed that, insects, telomeric DNA just set short repeats, very long sequence consisting (TTAGG) n (or other motifs), regularly specifically interrupted retrotransposons, motifs diverse terms their length nucleotide composition. The number assemblies GenBank database growing exponentially now exceeds thousand species. Therefore, exceptional prospects using data analysis beyond doubt.

Language: Английский

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Genomic evidence reveals three W-autosome fusions in Heliconius butterflies

PLoS Genetics, Journal Year: 2024, Volume and Issue: 20(7), P. e1011318 - e1011318

Published: July 18, 2024

Sex chromosomes are evolutionarily labile in many animals and sometimes fuse with autosomes, creating so-called neo-sex chromosomes. Fusions between sex autosomes have been proposed to reduce sexual conflict promote adaptation reproductive isolation among species. Recently, advances genomics fuelled the discovery of such fusions across tree life. Here, we discovered multiple leading sapho subclade classical adaptive radiation Heliconius butterflies. butterflies generally 21 very high synteny. However, five species show large variation chromosome number ranging from 60. We find that W is fused 4 all them. Two sister pairs subsequent 9 or 14, respectively. These make an ideal system for studying role radiations degeneration over time. Our findings emphasize capability short-read resequencing detect genomic signatures fusion events even when not explicitly assembled.

Language: Английский

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Cryptic Taxa Revealed through Combined Analysis of Chromosomes and DNA Barcodes: The Polyommatus ripartii Species Complex in Armenia and NW Iran

Insects, Journal Year: 2024, Volume and Issue: 15(7), P. 545 - 545

Published: July 19, 2024

The detection of cryptic species in complexes that have undergone recent speciation is often difficult, since many standard nuclear markers not yet accumulated differences between closely related taxa, and mitochondrial can be leveled out due to introgressions. In these cases, the use derived chromosomal characters such as non-ancestral numbers and/or unusual karyotype features may a solution delimitation problem. However, but similar karyotypes arise secondarily result homoplastic evolution, their interpretation homologies lead incorrect taxonomic conclusions. our study, we show combined DNA barcodes helps solve this problem identifies situations where each does work individually. Using approach, fauna Armenia adjacent Iran includes following taxa Polyommatus ripartii complex (haploid chromosome number, n parentheses): P. paralcestis (n = 90), kalashiani, subsp. nov close emmeli, sp. nov. 77–79), keleybaricus, 86), demavendi belovi 73–75), antonius, 71–73), admetus anatoliensis 79) eriwanensis 29–34). yeranyani synonymized with anatoliensis.

Language: Английский

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Polyommatine blue butterflies reveal unexpected integrity of the W sex chromosome amid extensive chromosome fragmentation

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: June 29, 2024

Abstract Chromosomal rearrangements are crucial in speciation, acting as barriers to gene flow. Holocentric chromosomes, such those Lepidoptera, can facilitate karyotype changes. Despite chromosome fusions being more common, speciation events mostly linked fissions. Notable karyotypic variation is observed three clades of the subfamily Polyommatinae (Lycaenidae), with numbers ranging from n = 10 225. This study used flow cytometry and molecular cytogenetic analyses investigate genome sizes karyotypes several species genera Polyommatus Lysandra derived modal numbers. The findings show no support for polyploidy, supporting diversification via fragmentation chromosomes. Species high have larger genomes, which indicates a potential role mobile elements but contradicts hypothesis holocentric drive. Telomeric signals were detected at ends fragmented No interstitial telomeric sequences on autosomes. Interstitial sex however, revealed multiple systems dorylas icarus , two races differing constitution latter. Pool-seq coverage indicated shared fusion chromosomes an autosome bearing rDNA locus, followed by 20 Czech population. Notably, W resists fragmentation, likely due epigenetic silencing protecting it activity elements.

Language: Английский

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