The fourspine stickleback (Apeltes quadracus) has an XY sex chromosome system with polymorphic inversions on both X and Y chromosomes

PLoS Genetics, Journal Year: 2025, Volume and Issue: 21(5), P. e1011465 - e1011465

Published: May 9, 2025

Teleost fish are well-known for possessing a diversity of sex chromosomes and undergoing frequent turnovers these chromosomes. However, previous studies have mainly focused on variation between species, while comparatively little attention has been given to chromosome polymorphisms within which may capture early stages changes. To better understand the evolution chromosomes, we used fourspine stickleback ( Apeltes quadracus ) as model organism. Previous cytogenetic suggested that females this species possessed ZW heteromorphic system. genetic crosses our whole-genome sequencing three geographically distinct wild populations revealed A. an XY 23. This not previously identified in any other indicating recent turnover. We also two genes - rxfp2a zar1l novel candidate determination genes. Notably, observed inversions both X Y different populations, resulting distinctive patterns differentiation across populations. The new intraspecies inversion provide excellent system future work assessing relative fitness effects inversions, will enable testing theoretical models about drivers

Language: Английский

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Chromosomal rearrangements and the first indication of an ♀X₁X₁X₂X₂/♂X₁X₂Y sex chromosome system in Rineloricaria fishes (Teleostei: Siluriformes)

Journal of Fish Biology, Journal Year: 2022, Volume and Issue: 102(2), P. 443 - 454

Published: Nov. 25, 2022

Rineloricaria is the most diverse genus within freshwater fish subfamily Loricariinae, and it widely distributed in Neotropical region. Despite limited cytogenetic data, records from southern south-eastern Brazil suggest a high rate of chromosomal rearrangements this genus, mirrored remarkable inter- intraspecific karyotype variability. In present work, we investigated features teffeana, an endemic representative northern Brazil, using both conventional molecular techniques. We revealed different diploid chromosome numbers (2n) between sexes (33♂/34♀), which suggests presence ♀X1 X1 X2 /♂X1 Y multiple sex system. The male-limited was largest only biarmed element karyotype, implying Y-autosome fusion as probable mechanism behind its origination. C-banding low amounts constitutive heterochromatin, mostly confined to (peri)centromeric regions chromosomes (including Y) but also occupying distal few pairs. localization 18S ribosomal DNA (rDNA) clusters single site on pair 4, adjacent 5S rDNA cluster. Additional loci were autosome 8, chromosome, presumed point chromosome. probe for telomeric repeat motif (TTAGGG)n signals variable intensities at ends all except where no detectable evidenced. Male-to-female comparative genomic hybridization sex-specific or sex-biased repetitive accumulations, suggesting presumably level neo-Y differentiation. provide evidence that sites might have played role formation putative system fusions originate through mechanisms among species.

Language: Английский

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Evaluating the role of sexual antagonism in the evolution of sex chromosomes: new data from fish

Current Opinion in Genetics & Development, Journal Year: 2023, Volume and Issue: 81, P. 102078 - 102078

Published: June 26, 2023

The recent increase in available molecular and genomic data for diverse taxa helps to shed new light on long-standing theories. Research into sex chromosome evolution has particularly benefited from a growing number of studies fish, motivated by their highly mechanisms determination. Sexual antagonism is regularly cited as an influential force emergence; however, this so far proves difficult demonstrate. In review, we highlight developments the investigation sexual research fish. We find strong emphasis placed study-organism specific features patterns recombination, rather than evidence comprehensive role antagonism. light, discuss alternative models evolution. conclude that fish represents key resource further research, provided attention given species-specific effects while simultaneously integrating comparative across vital understanding proposed models.

Language: Английский

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Independent Evolution of Sex Chromosomes and Male Pregnancy–Related Genes in Two Seahorse Species

Molecular Biology and Evolution, Journal Year: 2022, Volume and Issue: 40(1)

Published: Dec. 29, 2022

Unlike birds and mammals, many teleosts have homomorphic sex chromosomes, changes in the chromosome carrying sex-determining locus, termed "turnovers", are common. Recent turnovers allow studies of several interesting questions. One question is whether new regions evolve to become completely non-recombining, if so, how why. Another (as predicted) evolutionary that benefit one accumulate newly sex-linked region. To study these questions, we analyzed genome sequences two seahorse species Syngnathidae, a fish group which evolved unique structure, male brood pouch. We find both XY systems, but their pairs not homologs, implying at least turnover event has occurred. The Y-linked occupy 63.9% 95.1% entire do exhibit extensive sequence divergence with X-linked homologs. evidence for occasional recombination between extant chromosomes may account homomorphism. argue did by suppression after turnover, ancestral nature low crossover rates regions. With such an landscape, can instantly create Finally, test adaptive evolution pouch-related genes they became seahorse.

Language: Английский

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Turnover of sex chromosomes in the Lake Tanganyika cichlid tribe Tropheini (Teleostei: Cichlidae)

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: Jan. 30, 2024

Sex chromosome replacement is frequent in many vertebrate clades, including fish, frogs, and lizards. In order to understand the mechanisms responsible for sex turnover early stages of divergence, it necessary study lineages with recently evolved chromosomes. Here we examine evolution a group African cichlid fishes (tribe Tropheini) which began diverge from one another less than 4 MYA. We have evidence previously unknown system, preliminary indications several additional systems not reported this group. find high frequency estimate minimum 14 turnovers tribe. date origin most common determining system tribe (XY-LG5/19) near base two major sub-clades tribe, about 3.4 MY ago. Finally, observe variation size sex-determining region that suggests independent evolutionary strata species shared sex-determination system. Our results illuminate rapid rate Tropheini set stage further studies dynamics

Language: Английский

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Partial sex linkage and linkage disequilibrium on the guppy sex chromosome

Molecular Ecology, Journal Year: 2022, Volume and Issue: 31(21), P. 5524 - 5537

Published: Aug. 25, 2022

The guppy Y chromosome has been considered a model system for the evolution of suppressed recombination between sex chromosomes, and it proposed that complete sex-linkage evolved across about 3 Mb surrounding this fish's sex-determining locus, followed by suppression further 7 23 XY pair, forming younger "evolutionary strata". Sequences genome show is very similar to X chromosome. Knowing which parts are completely nonrecombining, whether there indeed large nonrecombining region, important understanding its evolution. Here, we describe analyses PoolSeq data in samples from within multiple natural populations Trinidad, yielding new results support previous evidence occasional X. We detected recent demographic changes, notably downstream have higher synonymous site diversity than upstream ones other expected signals bottlenecks. associations sequence variants rather divergence under lack recombination. Although infrequent, frequent enough with SNPs can suggest region locus must be located. Diversity elevated physically chromosome, conforming predictions infrequent carries one or more sexually antagonistic polymorphisms. However, no consistently male-specific were found, supporting suggestion any sex-linked may small.

Language: Английский

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The fate of recessive deleterious or overdominant mutations near mating-type loci under partial selfing

Peer Community Journal, Journal Year: 2023, Volume and Issue: 3

Published: Jan. 27, 2023

Large regions of suppressed recombination having extended over time occur in many organisms around genes involved mating compatibility (sex-determining or mating-type genes). The sheltering deleterious alleles has been proposed to be such expansions. However, the dynamics mutations partially linked are not well understood, especially finite populations. In particular, under what conditions likely maintained for long enough near mating-compatibility remains evaluated, selfing, which generally increases purging rate mutations. Using a branching process approximation, we studied fate new overdominant mutation diploid population, considering locus carrying two permanently heterozygous alleles, and at appears. We obtained analytical numerical results on probability mutation. investigated impact between loci system (outcrossing, intra inter-tetrad selfing) maintenance found that presence fungal-like (i.e. preventing always sheltered i.e. it decreased increased effect was higher case automixis (intra-tetrad selfing). This may contribute explain why evolutionary strata suppression mostly automictic (pseudo-homothallic) fungi. also showed rare events during strikingly times could occur, suggesting can indeed accumulate scales. conclusion, our show that, although selfing purges mutations, these very locus, promote evolution sex-related chromosomes.

Language: Английский

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Worse than nothing at all: the inequality of fusions joining autosomes to the PAR and non-PAR portions of sex chromosomes

PeerJ, Journal Year: 2024, Volume and Issue: 12, P. e17740 - e17740

Published: July 23, 2024

Chromosomal fusions play an integral role in genome remodeling and karyotype evolution. Fusions that join a sex chromosome to autosome are particularly abundant across the tree of life. However, previous models on establishment such have not accounted for physical structure chromosomes. We predict fusion joining pseudoautosomal region (PAR) will remain stable, switch from X Y each generation due recombination. produced forward-time population genetic simulation explore outcomes both PAR non-PAR The model can simulate containing sexually antagonistic locus either or end chromosome. Our is diploid, two-locus, biallelic. results show clear pattern where favored presence sexual antagonism, whereas disfavored antagonism.

Language: Английский

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Sexual antagonism and sex determination in three syngnathid species alongside a male pregnancy gradient

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: Sept. 1, 2023

Abstract The allocation of energy towards gamete production, parental care, mate choice, sex roles, and sexual dimorphism generates divergence in selection pressures between the sexes, leading to opposing fitness strategies antagonism (SA). Due shared genetic makeup, a single genomic locus can contain gene or allele with differing impacts on each sex. This intralocus conflict be resolved via intersex bias expression and/or formation sex-linked regions, that may also regulate determination. Sex determination (SD) encompasses environmental SD (ESD), monogenic SD, polygenic SD. Occasionally, shifts from one another occur. While precise mechanisms driving these are unknown, SA is believed major contributor. To investigate link we selected three syngnathid species along gradient male pregnancy evolved different roles intensities dimorphism. By looking at (Fst) sex-biased patterns, uncovered role competition, rather than pregnancy, primarily drive SA. Furthermore, identified processes related non-coding RNAs biased as mediators Most notably, discovered intraspecies chromosome polymorphism Hippocampus erectus . Overall, report important details interplay suggest understanding its resolution crucial for unraveling evolution diverse species.

Language: Английский

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The genomic architecture of a continuous color polymorphism in the European barn owl (Tyto alba)

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: April 4, 2023

Abstract The maintenance of color polymorphism in populations has fascinated evolutionary biologists for decades. Studies variation wild often focus on discrete traits exhibiting simple inheritance patterns, while studies continuously varying remain rare. Here, we studied the continuous white to rufous European barn owl ( Tyto alba ). Using a Genome Wide Association approach whole-genome data 75 owls sampled across Europe, identified, addition previously known MC1R mutation, two regions involved this polymorphism. We show that combination three explains 80.37% (95% credible interval 58.45 100%) variation. Among newly identified regions, one sexual chromosome (Z) shows large signal differentiation Swiss population when contrasting individuals with different morph but same genotype. suggest it may play role dimorphism observed locally species. These results, uncovering new genomic provide keys better understand molecular bases as well mechanisms responsible its at both continental and local scales.

Language: Английский

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