scholarly journals Identification of the master sex determining gene in Northern pike (Esox lucius) reveals restricted sex chromosome differentiation

2019 ◽  
Author(s):  
Qiaowei Pan ◽  
Romain Feron ◽  
Ayaka Yano ◽  
René Guyomard ◽  
Elodie Jouanno ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Wild Population ◽  
Northern Pike ◽  
Esox Lucius ◽  
Telomeric Region ◽  
Male Genome ◽  
Long Reads ◽  
Male Specific

AbstractTeleost fishes, thanks to their rapid evolution of sex determination mechanisms, provide remarkable opportunities to study the formation of sex chromosomes and the mechanisms driving the birth of new master sex determining (MSD) genes. However, the evolutionary interplay between the sex chromosomes and the MSD genes they harbor is rather unexplored. We characterized a male-specific duplicate of the anti-Müllerian hormone (amh) as the MSD gene in Northern Pike (Esox lucius), using genomic and expression evidences as well as by loss-of-function and gain-of-function experiments. Using RAD-Sequencing from a family panel, we identified Linkage Group (LG) 24 as the sex chromosome and positioned the sex locus in its sub-telomeric region. Furthermore, we demonstrated that this MSD originated from an ancient duplication of the autosomal amh gene, which was subsequently translocated to LG24. Using sex-specific pooled genome sequencing and a new male genome sequence assembled using Nanopore long reads, we also characterized the differentiation of the X and Y chromosomes, revealing a small male-specific insertion containing the MSD gene and a limited region with reduced recombination. Our study depicts an unexpected level of limited differentiation within a pair of sex chromosomes harboring an old MSD gene in a wild population of teleost fish, highlights the pivotal role of genes from the amh pathway in sex determination, as well as the importance of gene duplication as a mechanism driving the turnover of sex chromosomes in this clade.Author SummaryIn stark contrast to mammals and birds, teleosts have predominantly homomorphic sex chromosomes and display a high diversity of sex determining genes. Yet, population level knowledge of both the sex chromosome and the master sex determining gene is only available for the Japanese medaka, a model species. Here we identified and provided functional proofs of an old duplicate of anti-Müllerian hormone (Amh), a member of the Tgf-β family, as the male master sex determining gene in the Northern pike, Esox lucius. We found that this duplicate, named amhby (Y-chromosome-specific anti-Müllerian hormone paralog b), was translocated to the sub-telomeric region of the new sex chromosome, and now amhby shows strong sequence divergence as well as substantial expression pattern differences from its autosomal paralog, amha. We assembled a male genome sequence using Nanopore long reads and identified a restricted region of differentiation within the sex chromosome pair in a wild population. Our results provide insight on the conserved players in sex determination pathways, the mechanisms of sex chromosome turnover, and the diversity of levels of differentiation between homomorphic sex chromosomes in teleosts.

scholarly journals Reconstruction of the birth of a male sex chromosome present in Atlantic herring

2020 ◽  
Vol 117 (39) ◽  
pp. 24359-24368
Author(s):  
Nima Rafati ◽  
Junfeng Chen ◽  
Amaury Herpin ◽  
Mats E. Pettersson ◽  
Fan Han ◽  
...  
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Small Region ◽  
Atlantic Herring ◽  
Genes Encoding ◽  
Molecular Machinery ◽  
Suppressed Recombination ◽  
Male Specific

The mechanisms underlying sex determination are astonishingly plastic. Particularly the triggers for the molecular machinery, which recalls either the male or female developmental program, are highly variable and have evolved independently and repeatedly. Fish show a huge variety of sex determination systems, including both genetic and environmental triggers. The advent of sex chromosomes is assumed to stabilize genetic sex determination. However, because sex chromosomes are notoriously cluttered with repetitive DNA and pseudogenes, the study of their evolution is hampered. Here we reconstruct the birth of a Y chromosome present in the Atlantic herring. The region is tiny (230 kb) and contains only three intact genes. The candidate male-determining gene BMPR1BBY encodes a truncated form of a BMP1B receptor, which originated by gene duplication and translocation and underwent rapid protein evolution. BMPR1BBY phosphorylates SMADs in the absence of ligand and thus has the potential to induce testis formation. The Y region also contains two genes encoding subunits of the sperm-specific Ca2+ channel CatSper required for male fertility. The herring Y chromosome conforms with a characteristic feature of many sex chromosomes, namely, suppressed recombination between a sex-determining factor and genes that are beneficial for the given sex. However, the herring Y differs from other sex chromosomes in that suppression of recombination is restricted to an ∼500-kb region harboring the male-specific and sex-associated regions. As a consequence, any degeneration on the herring Y chromosome is restricted to those genes located in the small region affected by suppressed recombination.

scholarly journals Male-specific restriction of recombination frequency in the sex chromosomes of the medaka, Oryzias latipes

1999 ◽  
Vol 73 (3) ◽  
pp. 225-231 ◽  
Author(s):  
MASARU MATSUDA ◽  
SAEMI SOTOYAMA ◽  
SATOSHI HAMAGUCHI ◽  
MITSURU SAKAIZUMI
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Recombination Frequency ◽  
Oryzias Latipes ◽  
Body Colour ◽  
Specific Restriction ◽  
Xx Males ◽  
Heterogametic Sex ◽  
Male Specific

In the medaka, Oryzias latipes, the mechanism of sex determination (XX/XY) can be revealed by genetic crosses using a body-colour gene, though it does not have cytologically recognizable sex chromosomes. The recombination restriction of sex chromosomes in heterogametic (XY) males has been demonstrated. To elucidate whether the recombination is prevented by the heterogamety of the sex chromosomes or by maleness, we examined the recombination frequencies among three loci located on the sex chromosomes (r, SL1 and SL2) in heterogametic males (XY), homogametic males (XX and YY), homogametic females (XX) and heterogametic females (XY). The recombination frequencies between r–SL1 and SL1–SL2 were as follows: 0, 0 (XY males); 0, 1·5 (XX males); 1·6% (YY males; 1·2%, 14·4% (XY females); 0·8%, 21·8% (XX females). These results indicate that the recombination restriction of the sex chromosomes in heterogametic males does not result from heterogametic sex chromosomes, but from maleness. Such sex-chromosome- specific recombination restriction in heterogametic sex may have triggered the differentiation of sex chromosomes in vertebrates.

scholarly journals The Diversity and Evolution of Sex Chromosomes in Frogs

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 483
Author(s):  
Wen-Juan Ma ◽  
Paris Veltsos
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Comparative Genomic ◽  
Ancestral State ◽  
Heteromorphic Sex Chromosomes ◽  
Genomic Studies ◽  
Evolutionary Trajectories ◽  
Heterogametic Sex

Frogs are ideal organisms for studying sex chromosome evolution because of their diversity in sex chromosome differentiation and sex-determination systems. We review 222 anuran frogs, spanning ~220 Myr of divergence, with characterized sex chromosomes, and discuss their evolution, phylogenetic distribution and transitions between homomorphic and heteromorphic states, as well as between sex-determination systems. Most (~75%) anurans have homomorphic sex chromosomes, with XY systems being three times more common than ZW systems. Most remaining anurans (~25%) have heteromorphic sex chromosomes, with XY and ZW systems almost equally represented. There are Y-autosome fusions in 11 species, and no W-/Z-/X-autosome fusions are known. The phylogeny represents at least 19 transitions between sex-determination systems and at least 16 cases of independent evolution of heteromorphic sex chromosomes from homomorphy, the likely ancestral state. Five lineages mostly have heteromorphic sex chromosomes, which might have evolved due to demographic and sexual selection attributes of those lineages. Males do not recombine over most of their genome, regardless of which is the heterogametic sex. Nevertheless, telomere-restricted recombination between ZW chromosomes has evolved at least once. More comparative genomic studies are needed to understand the evolutionary trajectories of sex chromosomes among frog lineages, especially in the ZW systems.

scholarly journals Evolution of a Multiple Sex-Chromosome System by Three-Sequential Translocations among Potential Sex-Chromosomes in the Taiwanese Frog Odorrana swinhoana

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 661
Author(s):  
Ikuo Miura ◽  
Foyez Shams ◽  
Si-Min Lin ◽  
Marcelo de Bello Cioffi ◽  
Thomas Liehr ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Rare Case ◽  
Sex Chromosome ◽  
Sex Chromosome System ◽  
Brown Frog ◽  
Male Specific

Translocation between sex-chromosomes and autosomes generates multiple sex-chromosome systems. It happens unexpectedly, and therefore, the evolutionary meaning is not clear. The current study shows a multiple sex chromosome system comprising three different chromosome pairs in a Taiwanese brown frog (Odorrana swinhoana). The male-specific three translocations created a system of six sex-chromosomes, ♂X1Y1X2Y2X3Y3 -♀X1X1X2X2X3X3. It is unique in that the translocations occurred among three out of the six members of potential sex-determining chromosomes, which are known to be involved in sex-chromosome turnover in frogs, and the two out of three include orthologs of the sex-determining genes in mammals, birds and fishes. This rare case suggests sex-specific, nonrandom translocations and thus provides a new viewpoint for the evolutionary meaning of the multiple sex chromosome system.

scholarly journals A 180 Myr-old female-specific genome region in sturgeon reveals the oldest known vertebrate sex determining system with undifferentiated sex chromosomes

2021 ◽  
Vol 376 (1832) ◽  
pp. 20200089
Author(s):  
Heiner Kuhl ◽  
Yann Guiguen ◽  
Christin Höhne ◽  
Eva Kreuz ◽  
Kang Du ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Specific Sequence ◽  
Genome Region ◽  
Acipenser Ruthenus ◽  
Determination System ◽  
Sex Determination System ◽  
Female Specific ◽  
Polyploidization Event

Several hypotheses explain the prevalence of undifferentiated sex chromosomes in poikilothermic vertebrates. Turnovers change the master sex determination gene, the sex chromosome or the sex determination system (e.g. XY to WZ). Jumping master genes stay main triggers but translocate to other chromosomes. Occasional recombination (e.g. in sex-reversed females) prevents sex chromosome degeneration. Recent research has uncovered conserved heteromorphic or even homomorphic sex chromosomes in several clades of non-avian and non-mammalian vertebrates. Sex determination in sturgeons (Acipenseridae) has been a long-standing basic biological question, linked to economical demands by the caviar-producing aquaculture. Here, we report the discovery of a sex-specific sequence from sterlet ( Acipenser ruthenus ). Using chromosome-scale assemblies and pool-sequencing, we first identified an approximately 16 kb female-specific region. We developed a PCR-genotyping test, yielding female-specific products in six species, spanning the entire phylogeny with the most divergent extant lineages ( A. sturio, A. oxyrinchus versus A. ruthenus, Huso huso ), stemming from an ancient tetraploidization. Similar results were obtained in two octoploid species ( A. gueldenstaedtii, A. baerii ). Conservation of a female-specific sequence for a long period, representing 180 Myr of sturgeon evolution, and across at least one polyploidization event, raises many interesting biological questions. We discuss a conserved undifferentiated sex chromosome system with a ZZ/ZW-mode of sex determination and potential alternatives. This article is part of the theme issue ‘Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)’.

scholarly journals A compendium of novel genomics technologies provides a chromosome-scale assembly and insights into the sex determining system of the Greenland Halibut

2021 ◽  
Author(s):  
Anne-Laure Ferchaud ◽  
Claire Merot ◽  
Eric Normandeau ◽  
Ioannis Ragoussis ◽  
Charles Babin ◽  
...  
Keyword(s):  
Sex Determination ◽  
Single Molecule ◽  
Sex Chromosome ◽  
Major Effect ◽  
Whole Genome Sequence ◽  
Greenland Halibut ◽  
Long Reads ◽  
Full Picture ◽  
High Conservation ◽  
High Level

Despite the commercial importance of Greenland Halibut (Reinhardtius hippoglossoides), important gaps still persist in our knowledge of this species, including its reproductive biology and sex determination mechanism. In this study, we combined single molecule sequencing of long reads (Pacific Sciences) with Chromatin Conformation Capture sequencing (Hi-C) data to provide the first chromosome-level genome reference for this species. The high-quality assembly encompassed more than 598 Megabases (Mb) assigned to 1 594 scaffolds (scaffold N50 = 25 Mb) with 96 % of its total length distributed among 24 chromosomes. The investigation of its syntenic relationships with other economically important flatfish species revealed a high conservation of synteny blocks among members of this phylogenetic clade. Sex determination analysis revealed that flatfishes do not escape the rule applied to other teleost fish and exhibit a high level of plasticity and turnover in sex-determination mechanisms. A whole-genome sequence analysis of 198 individuals allowed us to draw a full picture of the molecular sex determination (SD) system for Greenland Halibut, revealing that this species possesses a very nascent male heterogametic XY system, with a putative major effect of the sox2 gene, also described as the main SD driver in two other flatfishes. Interestingly, our study also suggested for the first time in flatfishes that a putative Y-autosomal fusion could be associated with a reduction of recombination typical of early steps of sex chromosome evolution.

scholarly journals The influence of the Robertsonian translocation Rb(X.2)2Ad on anaphase I non-disjunction in male laboratory mice

1989 ◽  
Vol 53 (2) ◽  
pp. 77-86 ◽  
Author(s):  
I.-D. Adler ◽  
R. Johannisson ◽  
H. Winking
Keyword(s):  
Sex Chromosomes ◽  
Robertsonian Translocation ◽  
Sex Chromosome ◽  
Light And Electron Microscopy ◽  
Normal Karyotype ◽  
Chromosome 2 ◽  
Male Genome ◽  
The Difference ◽  
Normal Pairing

SummaryA Robertsonian translocation in the mouse between theXchromosome and chromosome 2 is described. The male and female carriers of the Rb(X.2)2Ad were fertile. A homozygous/hemizygous line was maintained. The influence of theX-autosomal Robertsonian translocation on anaphase I non-disjunction in male mice was studied by chromosome counts in cells at metaphase II of meoisis and by assessment of aneuploid progeny. The results conclusively show that the inclusion of Rb2Ad in the male genome induces non-disjunction at the first meoitic division. In second metaphase cells the frequency of sex-chromosomal aneuploidy was 10·8%, and secondary spermatocytes containing two or no sex chromosome were equally frequent. The Rb2Ad males sired 3·9% sex-chromosome aneuploid progeny. The difference in aneuploidy frequencies in the germ cells and among the progeny suggests that the viability of XO and XXY individuals is reduced. The pairing configurations of chromosomes 2, Rb2Ad andYwere studied during meiotic prophase by light and electron microscopy. Trivalent pairing was seen in all well spread nuclei. Complete pairing of the acrocentric autosome 2 with the corresponding segment of the Rb2Ad chromosome was only seen in 3·2% of the cells analysed in the electron microscope. The pairing between theXand theYchromosome in the Rb2Ad males corresponded to that in males with normal karyotype. Reasons for sex-chromosomal non-disjunction despite the normal pairing pattern between the sex chromosomes may be seen in the terminal chiasma location coupled with the asynchronous separation of the sex chromosomes and the autosomes. The Rb2Ad chromosome can be useful for studies ofXinactivation, as a marker for parental derivation of theXchromosome and for mapping loci byin situhybridization.

scholarly journals Sex chromosome evolution: historical insights and future perspectives

2017 ◽  
Vol 284 (1854) ◽  
pp. 20162806 ◽  
Author(s):  
Jessica K. Abbott ◽  
Anna K. Nordén ◽  
Bengt Hansson
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Empirical Studies ◽  
Analytical Models ◽  
Specific Gene ◽  
Sex Chromosome Evolution ◽  
Current Thinking

Many separate-sexed organisms have sex chromosomes controlling sex determination. Sex chromosomes often have reduced recombination, specialized (frequently sex-specific) gene content, dosage compensation and heteromorphic size. Research on sex determination and sex chromosome evolution has increased over the past decade and is today a very active field. However, some areas within the field have not received as much attention as others. We therefore believe that a historic overview of key findings and empirical discoveries will put current thinking into context and help us better understand where to go next. Here, we present a timeline of important conceptual and analytical models, as well as empirical studies that have advanced the field and changed our understanding of the evolution of sex chromosomes. Finally, we highlight gaps in our knowledge so far and propose some specific areas within the field that we recommend a greater focus on in the future, including the role of ecology in sex chromosome evolution and new multilocus models of sex chromosome divergence.

scholarly journals Sex chromosome evolution in muscid flies

2019 ◽  
Author(s):  
Richard P. Meisel ◽  
Pia U. Olafson ◽  
Kiran Adhikari ◽  
Felix D. Guerrero ◽  
Kranti Konganti ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Rapid Evolution ◽  
House Fly ◽  
Stable Fly ◽  
Cytological Evidence ◽  
Blow Flies ◽  
Horn Fly ◽  
Future Work

AbstractSex chromosomes and sex determining genes can evolve fast, with the sex-linked chromosomes often differing between closely related species. A substantial body of population genetics theory has been developed and tested to explain the rapid evolution of sex chromosomes and sex determination. However, we do not know why the sex-linked chromosomes differ between some species pairs yet are relatively conserved in other taxa. Addressing this question will require comparing closely related taxa with conserved and divergent sex chromosomes and sex determination systems to identify biological features that could explain these rate differences. Cytological karyotypes suggest that muscid flies (e.g., house fly) and blow flies are such a taxonomic pair. The sex chromosomes appear to differ across muscid species, whereas they are highly conserved across blow flies. Despite the cytological evidence, we do not know the extent to which muscid sex chromosomes are independently derived along different evolutionary lineages. To address that question, we used genomic data to identify young sex chromosomes in two closely related muscid species, horn fly (Haematobia irritans) and stable fly (Stomoxys calcitrans). We provide evidence that the nascent sex chromosomes of horn fly and stable fly were derived independently from each other and from the young sex chromosomes of the closely related house fly (Musca domestica). We present three different scenarios that could have given rise to the sex chromosomes of horn fly and stable fly, and we describe how the scenarios could be distinguished. Distinguishing between these scenarios in future work could help to identify features of muscid genomes that promote sex chromosome divergence.

scholarly journals Sex determination without sex chromosomes

2021 ◽  
Vol 376 (1832) ◽  
pp. 20200109 ◽  
Author(s):  
Ceri Weber ◽  
Blanche Capel
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Metabolic Pathways ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Alternative Pathway ◽  
Cellular Processes ◽  
Molecular Events ◽  
Effects Of Temperature ◽  
Reptilian Species

With or without sex chromosomes, sex determination is a synthesis of many molecular events that drives a community of cells towards a coordinated tissue fate. In this review, we will consider how a sex determination pathway can be engaged and stabilized without an inherited genetic determinant. In many reptilian species, no sex chromosomes have been identified, yet a conserved network of gene expression is initiated. Recent studies propose that epigenetic regulation mediates the effects of temperature on these genes through dynamic post-transcriptional, post-translational and metabolic pathways. It is likely that there is no singular regulator of sex determination, but rather an accumulation of molecular events that shift the scales towards one fate over another until a threshold is reached sufficient to maintain and stabilize one pathway and repress the alternative pathway. Investigations into the mechanism underlying sex determination without sex chromosomes should focus on cellular processes that are frequently activated by multiple stimuli or can synthesize multiple inputs and drive a coordinated response. This article is part of the theme issue ‘Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)’.

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