Silencing transformer and transformer-2 in Zeugodacus cucurbitae causes defective sex determination with inviability of most pseudomales

transformer is a switch gene for sex determination in many insects, which cooperates with transformer-2 that is expressed in both sexes to regulate female differentiation, particularly in dipterans. Zeugodacus cucurbitae(Coquillett) is a very destructive pest worldwide, however, its sex determination pathway remains largely uncharacterized. Here, we show that the female sex ratio is sharply reduced with knockdown of either transformer or transformer-2 by RNA interference in early embryos of Z. cucurbitae. Most of the males grown from the embryos with transient transformer and transformer-2 suppression mated with wild-type females and produced mixed sex progeny, with one exception that produced only female progeny, and all of the few remaining males failed to mate with wild-type females and produced no progeny. The exceptional male and those males with mating failure were XX pseudomales as determined by the detection of Y chromosome-linked Maleness-on-the-Y, indicating that most XX pseudomales are not viable. The phenotypes of transformer and transformer-2 suggest that they play a key role in regulating sex determination and are required for female sexual development of Z. cucurbitae. Our results will be beneficial to the understanding of sex determination in Z. cucurbitae and can facilitate the development of genetic sexing strains for its biological control.

Investigation of sex determination in starry flounder(Platichthys stellatus)reveals sex chromosome evolution in Pleuronectiformes and identifies a sex-specific marker

The identification of sex chromosomes is fundamental for exploring the mechanism and evolution of sex determination.Platichthys stellatus,a species exhibiting clear sexual dimorphism and homomorphic chromosome pairs,has received limited research concerning its sex determination mechanisms.Clarifying the sex chromosome of P.stellatus will enhance our understanding of sex chromosome evolution in Pleuronectiformes.This study employed whole-genome resequencing to investigate the sex chromosome and sex determination system in P.stellatus.Notably,Chr23 was identified as the sex chromosome in P.stellatus,with the sex-determining region(SDR)occupying 48.1%of the chromosome and featuring an XX/XY system.Sex chromosome turnover was observed within Pleuronectiformes,with P.stellatus,Verasper variegatus,and Hippoglossus hippoglossus sharing a common ancestral karyotype.No inversions were detected within the SDR of P.stellatus,although chromosomal rearrangements between sex chromosomes and autosomes were identified.Additionally,a sex-specific marker for P.stellatus was ascertained,enabling genetic sex identification,with significant implications for improving breeding programs and aquaculture practices.

Overexpression of Kdm6b induces testicular differentiation in a temperature-dependent sex determination system

In reptiles,such as the red-eared slider turtle(Trachemys scripta elegans),gonadal sex determination is highly dependent on the environmental temperature during embryonic stages.This complex process,which leads to differentiation into either testes or ovaries,is governed by the finely tuned expression of upstream genes,notably the testis-promoting gene Dmrt1 and the ovary-promoting gene Foxl2.Recent studies have identified epigenetic regulation as a crucial factor in testis development,with the H3K27me3 demethylase KDM6B being essential for Dmrt1 expression in T.s.elegans.However,whether KDM6B alone can induce testicular differentiation remains unclear.In this study,we found that overexpression of Kdm6b in T.s.elegans embryos induced the male development pathway,accompanied by a rapid increase in the gonadal expression of Dmrt1 at 31°C,a temperature typically resulting in female development.Notably,this sex reversal could be entirely rescued by Dmrt1 knockdown.These findings demonstrate that Kdm6b is sufficient for commitment to the male pathway,underscoring its role as a critical epigenetic regulator in the sex determination of the red-eared slider turtle.

Sex Determination in Homo sapiens as a Multi-Step Process: Potential for Development of Variants and Sex Differences in Disease Risk

Reproduction via cis-binary mechanisms appears to have evolved fairly early in the evolution of complex organisms, and a system committed to prior to evolution of humans. While the evolution of a chromosomal-specific approach has been a successful strategy for survival of a large variety of species including humans, the fidelity of sex determination leading to 100% cis-binary outcomes is not achieved in many species, with evidence for homosexual or bisexual behaviour evident in more than 1500 species. Thus, such outcomes indicates that sex determination is a multi-step process and not a single event, and as such, could lead to the appearance of variants during the process which developed much earlier than humans. Variants could arise either due to intrinsic variation in the steps of determination, or also be influenced by environmental factors of a biological or psychological nature. In contrast to homosexual variants which do not require interventions such as hormone therapy or surgery, expression of gender dysphoria, is more based in psychology, but also has biological underpinnings and can be influenced by such hormonal interventions and surgery. While the numbers of those with gender dysphoria is small (~0.6% - 1.0% of population), the attention given to this issue raises the possibility of biological and psychological environmental factors impacting the emergence of some of those expressing gender dysphoria. Furthermore, transitioning from male-to-female or female-to-male can have consequences regarding disease risks latter in life, including the appearance of autoimmune diseases. This review will attempt to review some of the evidence regarding sex determination, discuss why the system has potentially not been improved upon during evolution, how a potential role for sex chromosome function on neurodevelopment may be central to variation in humans, and how commitment to the current strategy is likely integrated into other sex-related events such as puberty, pregnancy, and menopause to ensure species survival. It will also discuss how variants in sex determination could contribute to sex differences in disease risk and how epigenetic modifications could play a role in such risk. .

Identification of a Sex-Associated RAPD Marker in Ginkgo biloba

The random amplified polymorphic DNA (RAPD) technique was used to amplify DNA fragment, aiming at finding markers linked to the sex determination in Ginkgo biloba L. One thousand and two hundred random decamers had been screened. Of the 8 372 RAPD bands, only a 682 bp RAPD marker generated by a primer (S1478) of random decamer sequence, named S1478-682, was found to be associated with the male plants. This marker was present in all male plants and absent in all female plants. Ginkgo trees collected in both Beijing and Shenyang, China were tested using primer S1478. Positive results were obtained, suggesting S1478-682 could be utilized as a reliable RAPD marker to detect the sexuality of Ginkgo.

Male sex determination： insights into molecular mechanisms

Disorders of sex development often arise from anomalies in the molecular or cellular networks that guide the differentiation of the embryonic gonad into either a testis or an ovary, two functionally distinct organs. The activation of the Y-linked gene Sry （sex- determining region Y） and its downstream target Sox9 （Sry box-containing gene 9） triggers testis differentiation by stimulating the differentiation of Sertoli cells, which then direct testis morphogenesis. Once engaged, a genetic pathway promotes the testis development while actively suppressing genes involved in ovarian development. This review focuses on the events of testis determination and the struggle to maintain male fate in the face of antagonistic pressure from the underlying female programme.

Expression of Sex-Related Genes in Chicken Embryos During Male-to-Female Sex Reversal Exposure to Diethylstilbestrol

Sex emerges out of a delicate dance between a variety of promale, anti-male, and possibly profemale genes. To investigate the role that sex-related genes play in sex determination and gonadal differentiation of fowl, we constructed a male-to- female sex-reversal model of chick induced by diethylstilbestrol （DES） at onset of incubation （E0）. The results of semi- quantitative PCR showed that the expression of Sf1, the orphan nuclear receptor steroidogenic factor-1 gene, was put forward from E7d to E5d and up-regulated during E5-7d; the Dmrt1, the double sex and the Mab-3 related to transcription factor 1 gene, was down-regulated during E3-7d. Meanwhile, anti-Müllerian hormone gene （Amh） expressed at a similar level in the genetic females and sex-reversal females before E7d, while no expression products of the three female-specific genes Wpkci, Fet1 and Foxl2 were detected in male-to-female embryos. These findings suggest that the expression of some certain sex-related genes, induced by the exogenous estrogen during period of sex determination and gonadal differentiation, results in the male-to-female sex reversal. Moreover, high activity of Sf1 gene during E5-7d might be related to the profemale process, while low activity of Dmrt1 gene during E3-5d might be anti-male. The expression activity of Amh gene might only contribute to the promale process after E7d, however, it is possibly not an anti-female gene in chick embryos.

Maleness-on-the-Y(MoY) orthologue is a key regulator of male sex determination in Zeugodacus cucurbitae(Diptera:Tephritidae)

The initiation of sex differentiation in insects is regulated by primary sex determination signals.In the Medfly Ceratitis capitata and other tephritids,Maleness-on-the-Y(MoY) is the master gene for male sex determination.However,the primary signal in Zeugodacus cucurbitae(Coquillett),a very destructive tephritid pest across the world,remains ambiguous.In this study,we have isolated and characterized the Medfly MoY homolog in Z.cucurbitae,ZcMoY.ZcMOY protein shows high sequence conservation to its homologs in Bactrocera species.ZcMoY transcription begins and peaks at very early embryonic stages and then becomes undetectable except the testes and heads of day 1 male adults.Silencing ZcMoY in early embryos by RNAi causes abnormal external genitalia and interior reproductive organs,giving rise to intersexes and feminization of XY individuals.The expression pattern and knockdown phenotypes of ZcMoY indicate that ZcMoY plays a key role in regulating sex determination of Z.cucurbitae males.Our findings will help the understanding of sex determination in Z.cucurbitae and facilitate the development of genetic sexing strains in its biological control.

Sex Determination Mechanisms in Fish

In fish,sex determination(SD) system shows high variation. The SD mechanisms include environmental and genetic regulation. The research on SD system and related genes in intensively studied fish species was reviewed. Although some genes have been described as sex-related,only DMRT1bY can be considered as a master sex determination gene and none of them has been utilized in aquaculture. The variation of fish SD system,the importance of sex-related genes in evolution research and the relations between environmental factors and sex-related genes were also discussed. The fish sex determination mechanism remains largely unknown. Further research needs to be done considering the significance of fish SD studies in basic and applied aspects.

Identification and Characterization of Gene SpDMRT99B and Its Sex-Biased Expression Profile in the Mud Crab,Scylla paramamosain

The doublesex and mab-3 related transcription factor(DMRT)gene family is conserved from invertebrates to humans.The functions of DMRT are mainly involved in sex development and the formation of many tissues and organs.In this study,a DM(Doublesex/Mab-3-domain gene was identified in the mud crab Scylla paramamosain,and was named SpDMRT99B because of its many similarities to arthropod DMRT99B and phylogenetically close relationship with arthropod DMRT99B.The cDNA of SpDMRT99B gene is 1249 bp in length,encoding 224 amino acids.From 254 bp to 928 bp there is a conserved DM domain.No transmembrane domain was identified.Through multiple amino acid alignment and phylogenetic tree analysis,the closest gene to SpDMRT99B is Eriocheir sinensis DMRT99B,followed by Macrobrachium rosenbergii and Drosophila melanogaster DMRT99B.The expressions of the gene were characterized in different tissues of female and male crabs during early development period of crab individuals,as well as in different development periods of gonads.The results showed that SpDMRT99B gene is significantly highly expressed in testis than in ovary and other tissues.The expression level of SpDMRT99B in testis at different stages is significantly higher than that in ovary,and it is particularly highly expressed in immature testis.In early developmental stages of larvae,the expressions of SpDMRT99B remain at a low level and reach a peak at zoea stage I when the body segments shape up.It is speculated that SpDMRT99B gene might be involved in the gonadal development process and somitogenesis of S.paramamosain.

The Effect of the Cyp19a1 Gene Methylation Modification on Temperature-dependent Sex Determination of Reeves' Turtle(Mauremys reevesii)

Temperature-dependent sex determination（TSD） is a type of environmental sex determination in which the sex of the embryos depends on the ambient temperature; however,the molecular mechanisms governing this process remain unknown.Aromatase,encoded by the cyp19a1 gene,which converts androgens into estrogens in animals,was considered to be the key gene for TSD.In this study,the 5＇-flanking region of the cyp19a1 gene in Reeves＇ turtle（Mauremys reevesii） was cloned,and the promoter region was identified using the luciferase reporter assay.Then the eggs of Reeves＇ turtle were incubated at different temperatures（26°C： male-biased temperature; 29°C： non-sex-biased temperature and 32°C： female-biased temperature）.During the thermosensitive period,the adrenal kidney gonad complexes（AKG） were sampled.DNA methylation analysis of the AKG samples showed that the promoter region of the cyp19a1 gene was significantly de-methylated in the female-biased temperature regime（P＆lt;0.01）.Quantitative analysis of the cyp19a1 gene and estrogen by q PCR and Elisa assay showed that the expression level of the cyp19a1 gene and estrogen content were both upregulated significantly at the female-biased temperature（P＆lt;0.01）.These results indicated that the de-methylation response of the cyp19a1 gene to incubation temperature,especially at the female-biased temperature,could lead to temperature-specific expression of aromatase and increased estrogen levels,which may further determine gonadal development in Reeves＇ turtle.These findings provide insights into the genetic mechanisms underlying TSD.

Prognostic significance of sex determining region Y-box 2,Ecadherin,and vimentin in esophageal squamous cell carcinoma

BACKGROUND Sex determining region Y-box 2(SOX2) can promote squamous cell carcinoma(SSC) because it regulates the migration and invasion of several different types of squamous carcinoma cells.However,few studies have examined the prognostic value of SOX2 and its effect on the epithelial-mesenchymal transition(EMT) in esophageal SSC(ESCC),a cancer characterized by high invasion and rapid metastasis.AIM To verify the relationship of SOX2 and the EMT in ESCC and determine the prognostic value and significance of SOX2 and protein markers of the EMT in ESCC.METHODS One hundred and eighty-five postsurgical ESCC patients were retrospectively examined.Immunohistochemistry was used to detect SOX2,E-cadherin,and vimentin in ESCC tissues.The chi-square test was used to determine the relationships of the expression of these proteins with clinical data.Kaplan-Meier survival curves were used to evaluate factors associated with overall survival(OS).RESULTS SOX2 and vimentin had high expression in ESCC tissues and correlated with the depth of local carcinoma invasion.SOX2 expression had positive correlations with tumor size,vimentin expression,and the EMT,and a negative correlation with Ecadherin expression.Expression of SOX2 and vimentin had negative correlations with OS.SOX2 expression was an independent prognostic risk factor for poor OS in patients with ESCC.CONCLUSION SOX2 expression was an independent risk factor for OS in patients with ESCC and its expression had a positive correlation with the expression of vimentin,a classic marker of the EMT.SOX2 promoted the migration and invasion of ESCC,and this may related to its effect on vimentin in promoting the EMT.

Noninvasive Prenatal Diagnosis of Fetal Sex by Single-cell PEP-PCR Method

A new method for noninvasive prenatal diagnosis of fetal sex was developed by using single cell PEP PCR techniques. Micromamipulation techniques were used to obtain single fetal cells from 273 maternal blood samples. The genome of single cells was preamplified by PEP and SRY genes were analyzed by PCR method. The SRY genes of 149 samples were detected by the new method among 153 samples carrying male fetus, while 119 out of 120 samples carrying female fetus were proved negative for SRY genes. The sensitivity and specificity of the new method were 97.39 % and 99.17 % respectively and the correct rate was 98.17 %. The new method has the advantage of high sensitivity and specificity in noninvasive prenatal diagnosis of fetal sex and provides the basis of other researches such as sex linked inherited diseases.

Analysis of SRY Gene in 8 Cases of Sex Abnormality

In order to investigate the relationship between sex dysplasia and sex-determining region Y (SRY) gene, 8 patients with sexual abnormality were analyzed by cytogenetic and molecular genetic methods. Fluorescence in situ hybridization (FISH) using PY3.4, X alpha satellite, and SRY probes was performed in each case to analyze the sex chromosome translocation and gene translocation. SRY gene was amplified by polymerase chain reaction (PCR) and its mutation was detected by direct sequencing. The results showed that among 8 patients, 5 were positive for SRY and the remaining negative for SRY. In the patients positive for SRY genes, 3 presented testes and the left 2 streak ovaries. In the patients negative for SRY, only one case presented testes, while 2 ovaries. Direct sequencing demonstrated that all SRY genes were normal in the patients positive for SRY genes. FISH technique demonstrated that SRY genes translocated from Ypter to Xpter in 2 46,XX phenotypic males positive for SRY genes. It was concluded that SRY gene is strongly involved in male sex determination, while a sequence of other genes may be taken into account in sexual development.

A Review of Sexual Determination and Differentiation in Crustacean

The prerequisite for monosex culture is to elucidate the molecular mechanism of sex determination and differentiation in crustaceans, as well as to explore the key genes that play a role in this process. Monosex culture technology based on crustacean economic species is of great importance in terms of genetic breeding and economic benefits of aquaculture. As a result, study into the mechanisms of sex determination and differentiation in crustaceans not only contributes to the current absence of basic theories of crustacean sexual mechanism, but also encourages technical innovation in aquaculture to increase overall economic efficiency. This study synthesizes and evaluates available research on sex determination and differentiation in crustaceans, and then provides recommendations for future research objectives and priorities in the field.

Offspring Sex Is Not Determined by Gestation Temperature in a Viviparous Lizard(Eremias multiocellata) from the Desert Steppe of Inner Mongolia

Sex-determining systems show a striking diversity not only among species, but also among popula tions. In reptiles, sex-determina tion is a continuum, from tempera ture-dependent sex determination(TSD) to genetic sex determination(GSD).The multi-ocellated racerunner(Eremias multiocellata)is reported to be a cryptic ZZ/ZW chromosomal TSD species, with male-biased sex ratios at high temperatures in two Gansu populations. However, the generality of the sex-determining pattern in different populations of this species remains unclear. To investigate the mode of sex determina tion in a popula tion of E.multiocellata from the desert steppe of Inner Mongolia,we first identified sex chromosomes via comparative genomic hybridization(CGH). We then conducted a thermal manipulation experiment to determine the effect of gestation temperature on offspring sex ratios.From the CGH studies we found that lizards from the Inner Mongolia population possessed ZZ/ZW sex chromosomes. However, our thermal manipulation experiment showed that gestation temperature did not affect the sex ratio of neonates in this population. In combination, these results rule out TSD in the Inner Mongolia population of E. multiocellata, and suggest that there is widespread geographic variation in the sexdetermining system of this species.

Sex determination and dif ferentiation in Aurelia sp.1: the absence of temperature dependence

Cnidarians, being regarded as ‘basal' metazoan animals, are considered to have relatively high plasticity in terms of sex reversal. In this study we used an experimental approach to demonstrate sexual diff erentiation and plasticity in benthic polyps and pelagic medusae of A urelia sp.1 maintained at dif ferent temperatures. Results indicated that in A urelia sp.1, sex diff erentiation has been determined at the polyp stage and that all medusae originating from a given polyp are, phenotypically, of the same sex. In addition, the sex of polyps budding from the same clone(either male or female) at dif ferent temperatures appears to be the same as that of the parent. The sex of medusae that had originated from a known-sex polyp was observed to remain the same as that of the parent, irrespective of differences in strobilation or rearing temperatures. These results indicate that the mechanism of sex determination of Aurelia sp.1. is not influenced by prevailing temperature regimes. A comparison of variability in terms of sexual plasticity of A urelia sp.1 with that of Hydrozoa and Anthozoa suggests that species characterized by a free-swimming medusa life stage have a high dispersal potential, which probably results in a lower rate of sex reversal.

Sex Determination and Sexual Organ Differentiation in Flowering Plants

The research in the genetics of sex determination and the differentiation of reproductive organs in flowering plants has long been a topic in recent years. Understanding the genetic and molecular mechanisms that control sex determination in flower- ing plants relies on detailed studies of the differentiation of sexual organs. Current theories about sex chromosomes have illuminated the mechanisms of plant sex determination. In addition, recent progress in cloning floral homeotic genes which regulate the identity of the floral organs has generated molecular markers to compare the developmental programs of male, female and hermaphrodite flowers in several species. In this review, the authors focus attention on these recent findings and provide a brief overview of the genetics of plant sex determination and the mechanism of sex determination gene expression and gene programs.

Sex Identification of Red-crowned Crane by the Polymerase Chain Reaction

Sex determining gene primers of Oriental White Stork were used to amplify sex-linked gene of the Red-crowned Crane′s W chromosome-specific by PCR for sex identification. The sexes of 7 couples of grown Red-crowned Cranes and 15 youngs were identified. Through DNA sequence analysis, the identity is 94.77% between Red-crowned Crane and Oriental White Stork. The results of this study suggest that the application of the polymerase chain reaction technique is practicable for determining sex in the Red-crowned Crane.

Sturgeon (Acipenser gueldenstaedtii) Acclimatization to Optimal Growth Conditions—A Case Study of Adaptation, Nutrition, Reproduction, and Sex Determination

The development of new agricultural industries is an important challenge for a region’s economic establishment. The connection between a research department at MIGAL Institute and biotechnology in aquaculture is an example (case study) of the interrelationships that also exist in other departments. This article describes the research conducted by the institute supporting the development of the aquaculture industry in Israel through the introduction of a relatively new fish species—the Russian sturgeon (Acipenser gueldenstaedtii), with the relevant information to be used for acclimatization to aquaculture conditions in northern Israel. Many aspects related to bringing a new species to Israel and working with this new industry to study its adaptation to existing conditions in the north of the country influenced the economic success of this new type of precision agriculture. This article describes the research on various aspects affecting the successful acclimatization of Russian sturgeon in northern Israel: introduction, food development, reproduction, hormone systems that control reproduction and growth, gonadal development, and molecular markers for sex determination, differentiation, and economic assessment of caviar production.