scholarly journals Sex-determination and sex chromosomes are shared across the radiation of dioecious Nepenthes pitcher plants

2017 ◽  
Author(s):  
Mathias Scharmann ◽  
T. Ulmar Grafe ◽  
Faizah Metali ◽  
Alex Widmer

AbstractPlants with separate sexes (dioecy) represent a minority but dioecy has evolved multiple times independently in plants. Our understanding of sex determination systems in plants and of the ecological factors and molecular changes associated with the evolution of dioecy remain limited. Here, we study the sex-determination system in dioecious plants that lack heteromorphic sex chromosomes and are not amenable to controlled breeding: Nepenthes pitcher plants. We genotyped wild populations of flowering males and females of three Nepenthes taxa using ddRAD-seq, and sequenced a male inflorescence transcriptome. We developed a novel statistical tool (privacy rarefaction) to distinguish true sex-specificity from stochastic noise in high-throughput sequencing data. Our results support XY-systems in all three Nepenthes taxa and in Silene latifolia which was used as a positive control for its known XY-system. The male-specific region of the Y chromosome showed little conservation among the three Nepenthes taxa, except for the essential pollen development gene DYT1 which was also male-specific in additional taxa. Hence, this homomorphic XY sex-determination system likely has a unique origin older than the crown of the genus Nepenthes at c. 17.7 My. In addition to the characterisation of the previously unknown sex chromosomes of Nepenthes, our work contributes an innovative, highly sensitive statistical method to efficiently detect sex-specific genomic regions in wild populations in general.

2021 ◽  
Vol 376 (1832) ◽  
pp. 20200089
Author(s):  
Heiner Kuhl ◽  
Yann Guiguen ◽  
Christin Höhne ◽  
Eva Kreuz ◽  
Kang Du ◽  
...  

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)’.


Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1020 ◽  
Author(s):  
Rovatsos ◽  
Altmanová ◽  
Augstenová ◽  
Mazzoleni ◽  
Velenský ◽  
...  

Chameleons are well-known, highly distinctive lizards characterized by unique morphological and physiological traits, but their karyotypes and sex determination system have remained poorly studied. We studied karyotypes in six species of Madagascan chameleons of the genus Furcifer by classical (conventional stain, C-banding) and molecular (comparative genomic hybridization, in situ hybridization with rDNA, microsatellite, and telomeric sequences) cytogenetic approaches. In contrast to most sauropsid lineages, the chameleons of the genus Furcifer show chromosomal variability even among closely related species, with diploid chromosome numbers varying from 2n = 22 to 2n = 28. We identified female heterogamety with cytogenetically distinct Z and W sex chromosomes in all studied species. Notably, multiple neo-sex chromosomes in the form Z1Z1Z2Z2/Z1Z2W were uncovered in four species of the genus (F. bifidus, F. verrucosus, F. willsii, and previously studied F. pardalis). Phylogenetic distribution and morphology of sex chromosomes suggest that multiple sex chromosomes, which are generally very rare among vertebrates with female heterogamety, possibly evolved several times within the genus Furcifer. Although acrodontan lizards (chameleons and dragon lizards) demonstrate otherwise notable variability in sex determination, it seems that female heterogamety with differentiated sex chromosomes remained stable in the chameleons of the genus Furcifer for about 30 million years.


2017 ◽  
Vol 4 (3) ◽  
pp. 160880 ◽  
Author(s):  
M. Pratlong ◽  
A. Haguenauer ◽  
S. Chenesseau ◽  
K.  Brener ◽  
G. Mitta ◽  
...  

Sexual reproduction is widespread among eukaryotes, and the sex-determining processes vary greatly among species. While genetic sex determination (GSD) has been intensively described in bilaterian species, no example has yet been recorded among non-bilaterians. However, the quasi-ubiquitous repartition of GSD among multicellular species suggests that similar evolutionary forces can promote this system, and that these forces could occur also in non-bilaterians. Studying sex determination across the range of Metazoan diversity is indeed important to understand better the evolution of this mechanism and its lability. We tested the existence of sex-linked genes in the gonochoric red coral ( Corallium rubrum , Cnidaria) using restriction site-associated DNA sequencing. We analysed 27 461 single nucleotide polymorphisms (SNPs) in 354 individuals from 12 populations including 53 that were morphologically sexed. We found a strong association between the allele frequencies of 472 SNPs and the sex of individuals, suggesting an XX/XY sex-determination system. This result was confirmed by the identification of 435 male-specific loci. An independent test confirmed that the amplification of these loci enabled us to identify males with absolute certainty. This is the first demonstration of a GSD system among non-bilaterian species and a new example of its convergence in multicellular eukaryotes.


Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 374 ◽  
Author(s):  
Svetlana A. Romanenko ◽  
Antonina V. Smorkatcheva ◽  
Yulia M. Kovalskaya ◽  
Dmitry Yu. Prokopov ◽  
Natalya A. Lemskaya ◽  
...  

The mandarin vole, Lasiopodomys mandarinus, is one of the most intriguing species among mammals with non-XX/XY sex chromosome system. It combines polymorphism in diploid chromosome numbers, variation in the morphology of autosomes, heteromorphism of X chromosomes, and several sex chromosome systems the origin of which remains unexplained. Here we elucidate the sex determination system in Lasiopodomys mandarinus vinogradovi using extensive karyotyping, crossbreeding experiments, molecular cytogenetic methods, and single chromosome DNA sequencing. Among 205 karyotyped voles, one male and three female combinations of sex chromosomes were revealed. The chromosome segregation pattern and karyomorph-related reproductive performances suggested an aberrant sex determination with almost half of the females carrying neo-X/neo-Y combination. The comparative chromosome painting strongly supported this proposition and revealed the mandarin vole sex chromosome systems originated due to at least two de novo autosomal translocations onto the ancestral X chromosome. The polymorphism in autosome 2 was not related to sex chromosome variability and was proved to result from pericentric inversions. Sequencing of microdissection derived of sex chromosomes allowed the determination of the coordinates for syntenic regions but did not reveal any Y-specific sequences. Several possible sex determination mechanisms as well as interpopulation karyological differences are discussed.


2020 ◽  
Author(s):  
Heiner Kuhl ◽  
Yann Guiguen ◽  
Christin Höhne ◽  
Eva Kreuz ◽  
Kang Du ◽  
...  

SummarySeveral 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 a ~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 vs. 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 My 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.


2017 ◽  
Author(s):  
Ben J. G. Sutherland ◽  
Ciro Rico ◽  
Céline Audet ◽  
Louis Bernatchez

ABSTRACTWhole genome duplication can have large impacts on genome evolution, and much remains unknown about these impacts. This includes the mechanisms of coping with a duplicated sex determination system and whether this has an impact on increasing the diversity of sex determination mechanisms. Other impacts include sexual conflict, where alleles having different optimums in each sex can result in sequestration of genes into non-recombining sex chromosomes. Sex chromosome development itself may involve sex-specific recombination rate (i.e. heterochiasmy), which is also poorly understood. Family Salmonidae is a model system for these phenomena, having undergone autotetraploidization and subsequent rediploidization in most of the genome at the base of the lineage. The salmonid master sex determining gene is known, and many species have non-homologous sex chromosomes, putatively due to transposition of this gene. In this study, we identify the sex chromosome of Brook Charr Salvelinus fontinalis and compare sex chromosome identities across the lineage (eight species, four genera). Although non-homology is frequent, homologous sex chromosomes and other consistencies are present in distantly related species, indicating probable convergence on specific sex and neo-sex chromosomes. We also characterize strong heterochiasmy with 2.7-fold more crossovers in maternal than paternal haplotypes with paternal crossovers biased to chromosome ends. When considering only rediploidized chromosomes, the overall heterochiasmy trend remains, although with only 1.9-fold more recombination in the female than the male. Y chromosome crossovers are restricted to a single end of the chromosome, and this chromosome contains a large interspecific inversion, although its status between males and females remains unknown. Finally, we identify QTL for 21 unique growth, reproductive and stress-related phenotypes to improve knowledge of the genetic architecture of these traits important to aquaculture and evolution.


Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2630
Author(s):  
Euna Jo ◽  
Seung-Jae Lee ◽  
Eunkyung Choi ◽  
Jinmu Kim ◽  
Jun-Hyuck Lee ◽  
...  

The brine shrimp Artemia has a ZW sex determination system with ZW chromosomes in females and ZZ chromosomes in males. Artemia has been considered a promising model organism for ZW sex-determining systems, but the genes involved in sex determination and differentiation of Artemia have not yet been identified. Here, we conducted transcriptome sequencing of female and male A. franciscana using PacBio Iso-Seq and Illumina RNA-Seq techniques to identify candidate sex determination genes. Among the 42,566 transcripts obtained from Iso-Seq, 23,514 were analyzed. Of these, 2065 (8.8%) were female specific, 2513 (10.7%) were male specific, and 18,936 (80.5%) were co-expressed in females and males. Based on GO enrichment analysis and expression values, we found 10 female-biased and 29 male-biased expressed genes, including DMRT1 and Sad genes showing male-biased expression. Our results showed that DMRT1 has three isoforms with five exons, while Sad has seven isoforms with 2–11 exons. The Sad gene is involved in ecdysteroid signaling related to molting and metamorphosis in arthropods. Further studies on ecdysteroid biosynthetic genes are needed to improve our understanding of Artemia sex determination. This study will provide a valuable resource for sex determination and differentiation studies on Artemia and other crustaceans with ZW systems.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 305
Author(s):  
Kenji Toyota ◽  
Hitoshi Miyakawa ◽  
Chizue Hiruta ◽  
Tomomi Sato ◽  
Hidekazu Katayama ◽  
...  

Mechanisms underlying sex determination and differentiation in animals are known to encompass a diverse array of molecular clues. Recent innovations in high-throughput sequencing and mass spectrometry technologies have been widely applied in non-model organisms without reference genomes. Crustaceans are no exception. They are particularly diverse among the Arthropoda and contain a wide variety of commercially important fishery species such as shrimps, lobsters and crabs (Order Decapoda), and keystone species of aquatic ecosystems such as water fleas (Order Branchiopoda). In terms of decapod sex determination and differentiation, previous approaches have attempted to elucidate their molecular components, to establish mono-sex breeding technology. Here, we overview reports describing the physiological functions of sex hormones regulating masculinization and feminization, and gene discovery by transcriptomics in decapod species. Moreover, this review summarizes the recent progresses of studies on the juvenile hormone-driven sex determination system of the branchiopod genus Daphnia, and then compares sex determination and endocrine systems between decapods and branchiopods. This review provides not only substantial insights for aquaculture research, but also the opportunity to re-organize the current and future trends of this field.


Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 43
Author(s):  
Thitipong Panthum ◽  
Nararat Laopichienpong ◽  
Ekaphan Kraichak ◽  
Worapong Singchat ◽  
Dung Ho My Nguyen ◽  
...  

The snakeskin gourami (Trichopodus pectoralis) has a high meat yield and is one of the top five aquaculture freshwater fishes in Thailand. The species is not externally sexually dimorphic, and its sex determination system is unknown. Understanding the sex determination system of this species will contribute to its full-scale commercialization. In this study, a cytogenetic analysis did not reveal any between-sex differences in chromosomal patterns. However, we used genotyping-by-sequencing to identify 4 male-linked loci and 1 female-linked locus, indicating that the snakeskin gourami tends to exhibit an XX/XY sex determination system. However, we did not find any male-specific loci after filtering the loci for a ratio of 100:0 ratio of males:females. This suggests that the putative Y chromosome is young and that the sex determination region is cryptic. This approach provides solid information that can help identify the sex determination mechanism and potential sex determination regions in the snakeskin gourami, allowing further investigation of genetic improvements in the species.


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