scholarly journals The Snakeskin Gourami (Trichopodus pectoralis) Tends to Exhibit XX/XY Sex Determination

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 43
Author(s):  
Thitipong Panthum ◽  
Nararat Laopichienpong ◽  
Ekaphan Kraichak ◽  
Worapong Singchat ◽  
Dung Ho My Nguyen ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sex Determination ◽  
Y Chromosome ◽  
Cytogenetic Analysis ◽  
Genotyping By Sequencing ◽  
Sexually Dimorphic ◽  
Determination System ◽  
Sex Determination System ◽  
Male Specific ◽  
Determination Mechanism

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.

scholarly journals Heterochiasmy facilitated the establishment of gsdf as a novel sex determining gene in Atlantic halibut

2020 ◽  
Author(s):  
Rolf Brudvik Edvardsen ◽  
Ola Wallerman ◽  
Tomasz Furmanek ◽  
Lene Kleppe ◽  
Patric Jern ◽  
...  
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Meiotic Recombination ◽  
Sequence Divergence ◽  
Atlantic Halibut ◽  
Specific Expression ◽  
Repeat Class ◽  
Determination System ◽  
Sex Determination System ◽  
Male Specific

Atlantic Halibut (Hippoglossus hippoglossus) has a X/Y genetic sex determination system, but the sex determining factor is not known. We produced a high-quality genome assembly and identified parts of chromosome 13 as the Y chromosome due to sequence divergence between sexes and segregation of sex genotypes in pedigrees. Linkage analysis revealed that all chromosomes exhibit heterochiasmy, i.e. male- and female restricted meiotic recombination intervals (MRR/FRR). We show that FRR/MRR intervals differ in nucleotide diversity and repeat class content and that this is true also for other Pleuronectidae species. We further show that remnants of a Gypsy-like transposable element insertion on chr13 promotes early male specific expression of gonadal somatic cell derived factor (gsdf). Less than 4 MYA, this male-determining element evolved on an autosomal FRR segment featuring pre-existing male meiotic recombination barriers, thereby creating a Y chromosome. We propose that heterochiasmy may facilitate the evolution of genetic sex determination systems.

SEX AND SUPERNUMERARY CHROMOSOMES IN THE DIOECIOUS GRASS SOHNSIA FILIFOLIA

1972 ◽  
Vol 14 (1) ◽  
pp. 175-180 ◽  
Author(s):  
D. N. Singh
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Supernumerary Chromosome ◽  
The Other ◽  
Male Plant ◽  
Diploid Male ◽  
Male And Female ◽  
Supernumerary Chromosomes ◽  
Determination System ◽  
Sex Determination System

A dioecious grass Sohnsia filifolia (Fourn.) Airy Shaw (Syn. Calamochloa filifolia Fourn.) from Mexico has been found to have 2n = 20 chromosomes in both male and female plants. The staminate plants have one chromosome much longer than the other chromosomes of the complement. One pistillate plant was found to have 30 chromosomes, among which the largest chromosome is quite similar to the largest component of the diploid male plant. The longest chromosome has been designated as the Y chromosome. An XY-mechanism of the Drosophilia type has been suggested for the sex determination system in this species. One small supernumerary chromosome was observed in the microsporocytes of some male plants, but was absent in roots.

scholarly journals Evidence for a genetic sex determination in Cnidaria, the Mediterranean red coral ( Corallium rubrum )

2017 ◽  
Vol 4 (3) ◽  
pp. 160880 ◽  
Author(s):  
M. Pratlong ◽  
A. Haguenauer ◽  
S. Chenesseau ◽  
K.  Brener ◽  
G. Mitta ◽  
...  
Keyword(s):  
Sex Determination ◽  
Strong Association ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Evolutionary Forces ◽  
Corallium Rubrum ◽  
Red Coral ◽  
Determination System ◽  
Sex Determination System ◽  
Male Specific

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.

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
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
High Throughput Sequencing ◽  
Silene Latifolia ◽  
Wild Populations ◽  
Sequencing Data ◽  
Pitcher Plants ◽  
Determination System ◽  
Sex Determination System ◽  
Male Specific

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.

scholarly journals Sex-Biased Gene Expression and Isoform Profile of Brine Shrimp Artemia franciscana by Transcriptome Analysis

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2630
Author(s):  
Euna Jo ◽  
Seung-Jae Lee ◽  
Eunkyung Choi ◽  
Jinmu Kim ◽  
Jun-Hyuck Lee ◽  
...  
Keyword(s):  
Sex Determination ◽  
Brine Shrimp ◽  
Model Organism ◽  
Enrichment Analysis ◽  
Go Enrichment ◽  
Determination System ◽  
Sex Determination System ◽  
Female Specific ◽  
Male Specific ◽  
Go Enrichment Analysis

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.

scholarly journals Identification of sex-linked markers in the sexually cryptic coco de mer: are males and females produced in equal proportions?

AoB Plants ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Emma J Morgan ◽  
Christopher N Kaiser-Bunbury ◽  
Peter J Edwards ◽  
Mathias Scharmann ◽  
Alex Widmer ◽  
...  
Keyword(s):  
Sex Ratios ◽  
Differential Mortality ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Determination System ◽  
Males And Females ◽  
Heterogametic Sex ◽  
Sex Determination System ◽  
Male Specific ◽  
Genetically Determined

Abstract Lodoicea maldivica (coco de mer) is a long-lived dioecious palm in which male and female plants are visually indistinguishable when immature, only becoming sexually dimorphic as adults, which in natural forest can take as much as 50 years. Most adult populations in the Seychelles exhibit biased sex ratios, but it is unknown whether this is due to different proportions of male and female plants being produced or to differential mortality. In this study, we developed sex-linked markers in Lodoicea using ddRAD sequencing, enabling us to reliably determine the gender of immature individuals. We screened 589 immature individuals to explore sex ratios across life stages in Lodoicea. The two sex-specific markers resulted in the amplification of male-specific bands (Lm123977 at 405 bp and Lm435135 at 130 bp). Our study of four sub-populations of Lodoicea on the islands of Praslin and Curieuse revealed that the two sexes were produced in approximately equal numbers, with no significant deviation from a 1:1 ratio before the adult stage. We conclude that sex in Lodoicea is genetically determined, suggesting that Lodoicea has a chromosomal sex determination system in which males are the heterogametic sex (XY) and females are homogametic (XX). We discuss the potential causes for observed biased sex ratios in adult populations, and the implications of our results for the life history, ecology and conservation management of Lodoicea.

How Evolutionarily Stable is the Xx/Xy Sex-Determination System?

1980 ◽  
Vol 12 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Bengt O. Bengtsson
Keyword(s):  
Sex Determination ◽  
Difficult Problem ◽  
Evolutionary Stability ◽  
Initial Increase ◽  
Mendelian Segregation ◽  
Numerical Equality ◽  
Determination System ◽  
Sex Determination System ◽  
Determination Mechanism ◽  
Evolutionarily Stable

The sex of a zygote is often decided by an XX/XY sex-determination mechanism. One important property of this system is the approximate numerical equality of the two sexes (at least at fertilization) due to mendelian segregation. Does the obvious evolutionary stability of the XX/XY sex-determination system pose a difficult problem to population genetics? We study the fate of new mutations occurring in populations with an XX/XY system, where the mutations are such that they change the sex-determination system. If such mutations occur frequently and the conditions for their initial increase are weak, then the evolutionary stability of the XX/XY system is hard to understand.

scholarly journals Assigning the Sex-Specific Markers via Genotyping-by-Sequencing onto the Y Chromosome for a Torrent Frog Amolops mantzorum

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 727 ◽  
Author(s):  
Wei Luo ◽  
Yun Xia ◽  
Bisong Yue ◽  
Xiaomao Zeng
Keyword(s):  
Sex Differences ◽  
Sex Determination ◽  
Candidate Gene ◽  
Y Chromosome ◽  
Light Microscope ◽  
Whole Genome Amplification ◽  
Genotyping By Sequencing ◽  
Whole Genome ◽  
Promoter Regions ◽  
Male Heterogamety

We used a genotyping-by-sequencing (GBS) approach to identify sex-linked markers in a torrent frog (Amolops mantzorum), using 21 male and 19 female wild-caught individuals from the same population. A total of 141 putatively sex-linked markers were screened from 1,015,964 GBS-tags via three approaches, respectively based on sex differences in allele frequencies, sex differences in heterozygosity, and sex-limited occurrence. With validations, 69 sex-linked markers were confirmed, all of which point to male heterogamety. The male specificity of eight sex markers was further verified by PCR amplifications, with a large number of additional individuals covering the whole geographic distribution of the species. Y chromosome (No. 5) was microdissected under a light microscope and amplified by whole-genome amplification, and a draft Y genome was assembled. Of the 69 sex-linked markers, 55 could be mapped to the Y chromosome assembly (i.e., 79.7%). Thus, chromosome 5 could be added as a candidate to the chromosomes that are particularly favored for recruitment in sex-determination in frogs. Three sex-linked markers that mapped onto the Y chromosome were aligned to three different promoter regions of the Rana rugosa CYP19A1 gene, which might be considered as a candidate gene for triggering sex-determination in A. mantzorum.

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