Phenotypic Sex Research Articles

Rxrs and their partner receptor genes inducing masculinization plausibly mediated by endocrine disruption in Paralichthys olivaceus

Retinoid X receptors (RXRs) can form homo- or heterodimers with orphan receptors involved in multiple intertwined signaling pathways. However, there is limited study on the formation of sex phenotypes and the regulation of steroidogenesis by RXRs in fish. Here, in Paralichthys olivaceus, we first indicated that PPARγ::RXRα was predictably a transcription factor for steroidogenesis genes, and Foxl2 and Dmrt1 were also transcription factors for rxrs and their partner receptor genes. When the flounder fry were exposed to LG100268 (LG, RXRs agonist, 50 mg/kg diet), the percentage of males increased from 50% to 71.4%. Before histological differentiation of the flounder ovary (3 cm TL) and testis (6 cm TL), the transcripts of rar β and rar γ (P < 0.05) were activated, and the steroidogenesis gene Hsd3b1 was down-regulated (P < 0.05). The ratios of testosterone (T)/17β-estradiol (E2) were all greatly increased (P < 0.05), and the ratio of 11-ketotestosterone (11-KT)/E2 was elevated at 3 cm TL. Moreover, LG was used to treat the cultured gonads in vitro (10 μM) and the fish with intraperitoneal injection in vivo (12 mg/kg body weight), respectively. LG was able to up-regulate rxr γ, rar γ, and ppar δ, and Hsd3b1 was significantly up-regulated (P < 0.05). The ratios of 11-KT/E2 in the culture medium and in the ovaries of the fish were decreased. Furthermore, the recombinant flounder Foxl2 protein was able to significantly down-regulate ppar γ (P < 0.05) and tr β (P < 0.01) in the ovaries in vitro, and the result of the Dmrt1 in the testes was opposite to that of the Foxl2, probably indicating a feedback loop between RXRs’ partner receptors and Foxl2/Dmrt1. These findings introduce for the first time the mode of action of RXRs on the flounder steroidogenesis and provide important data to learn the potential function of RXRs in fish sex differentiation and the potential role of RXRs in aquatic animals in the presence of water pollutants.

Exploring differentially expressed genes in hypothalamic, pars tuberalis and pineal gland transcriptomes in different sexual behavior phenotypes in rams using RNA-Seq.

Reproductive seasonality is a limiting factor in sheep production. Sexual behavior is a key element in reproductive efficiency, and this function is regulated by the hypothalamus-pituitary-gonadal (HPG) axis. To understand the mechanisms of sexual behavior, transcriptomic sequencing technology was used to identify differentially expressed genes (DEGs) in the hypothalamus (HT), pars tuberalis (PT) and pineal gland (PG) in Rasa Aragonesa rams with different sexual behavior. Bioinformatics analysis of the 16,401 identified genes by RNA-Seq revealed 103 and 12 DEGs in the HT and the PG, respectively, at a false discovery rate (FDR) of 5% with an absolute value of expression ≥ 1 (log2FC). However, no DEGs were found in the PT. Functional annotation and pathway enrichment analysis showed that DEGs of HT were enriched mainly in neuroactive ligand-receptor interactions and signaling pathways, including notable candidate genes such as MTNR1A, CHRNA2, FSHB, LHB, GNRHR, AVP, PRL, PDYN, CGA, GABRD, and TSHB, which play a crucial role in sexual behavior. The GnRH and cAMP signaling pathways were also highlighted. In addition, gene set enrichment analysis (GSEA) identified potential pathways, dominated mainly by biological process category, that could be responsible for the differences in sexual behavior observed in rams. The intracellular protein transport and pattern specification process were enriched within the PT and the transcription factor binding and protein ubiquitination pathways for the PG. Thus, these pathways together may play an important role in the regulation of the sexual behavior in Rasa Aragonesa rams through the hypothalamic-pituitary-gonadal axis. The validation of 5 DEGs using reverse transcription quantitative polymerase chain reaction (RT-qPCR) showed expression patterns like the found with RNA-Seq. Overall, these results contribute to understanding the genomic basis of sexual behavior in rams. Our study demonstrates that multiple networks and pathways orchestrate sexual behavior in sheep.

PMON33 Non-Syndromic SRY Negative 46 XX Testicular Disorder of Sex Development (DSD): A Rare Cause of Infertility

Abstract Introduction Male infertility can be categorized as endocrine and systemic disorders, primary testicular defects in spermatogenesis, sperm transport disorders and idiopathic male infertility. Chromosomal abnormalities are one of the primary testicular defects. The overall incidence of chromosome abnormalities in infertile men is estimated to be around 5.8%. XX male is a rare sex chromosomal disorder in infertile men. We present case of a young patient with infertility, azoospermia, hypergonadotropic hypogonadism and classical (46, XX) karyotype with negative FISH and SRY gene. Case report: 28-Year-old gentleman was referred to adult endocrinology clinic as part of work up for infertility. Initial work up included 2 semen analyses which were consistent with azoospermia. Examination revealed height 180 cm, weight 77 kg, a body mass index 24 kg/m2, normal phenotypic male without gynecomastia and had normal male pattern hair distribution. Genital examination showed normal male phallus without hypospadias, a hypoplastic scrotum, bilateral firm testes, with no varicocele or hydrocele. Labs were suggestive of compensated primary hypogonadism (FSH 47.9 mIU/ml, LH 20.4 mIU/ml, total testosterone 397.9 ng/dl by LC/MS, free testosterone 15.76 ng/dl by equilibrium dialysis, Inhibin B &amp;lt; 10 pg/ml, and anti-Mullerian hormone 0.390 ng/ml. Given normal testosterone levels, he was not started on testosterone replacement. Karyotype analysis revealed 46 XX and FISH was negative for SRY gene. CT imaging of abdomen and pelvis did not reveal any Mullerian structures, prostrate and seminal vesicles reported as normal. Patient met with a Urologist and was informed that testicular sperm extraction will not be a possibility for him. Patient had a detailed consultation with a geneticist for genetic and family counseling. Chromosome microarray analysis was obtained and was normal. Invitae Disorders of sex development (DSD) panel obtained for genetic sequencing of 53 genes including SOX-9, DHH, WNT4, WT1, was found to be non-diagnostic. Conclusion and Discussion SRY negative 46 XX male is a DSD and a rare genetic cause of male factor infertility, with a discrepancy between genotype and phenotypic sex. In the case presented, genetic work up for potential etiologies has been unrevealing. Further studies are needed to identify the genetic causes of the SRY negative 46 XX male phenotype. Physicians involved in care of these patients should orient with clinical management and prognosis. For Classical 46 XX Males seeking fertility, the current options include invitro-fertilization with donor sperm or adoption only. Testosterone replacement should be considered to correct hypogonadism for physical and sexual well-being. Genetic consultation should be sought in all these cases. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

PMON33 Non-Syndromic SRY Negative 46 XX Testicular Disorder of Sex Development (DSD); A rare cause of Infertility

Abstract Introduction Male infertility can be categorized as endocrine and systemic disorders, primary testicular defects in spermatogenesis, sperm transport disorders and idiopathic male infertility. Chromosomal abnormalities are one of the primary testicular defects. The overall incidence of chromosome abnormalities in infertile men is estimated to be around 5.8%. XX male is a rare sex chromosomal disorder in infertile men. We present case of a young patient with infertility, azoospermia, hypergonadotropic hypogonadism and classical (46, XX) karyotype with negative FISH and SRY gene. Case report: 28-Year-old gentleman was referred to adult endocrinology clinic as part of work up for infertility. Initial work up included 2 semen analyses which were consistent with azoospermia. Examination revealed height 180 cm, weight 77 kg, a body mass index 24 kg/m2, normal phenotypic male without gynecomastia and had normal male pattern hair distribution. Genital examination showed normal male phallus without hypospadias, a hypoplastic scrotum, bilateral firm testes, with no varicocele or hydrocele. Labs were suggestive of compensated primary hypogonadism (FSH 47.9 mIU/ml, LH 20.4 mIU/ml, total testosterone 397.9 ng/dl by LC/MS, free testosterone 15.76 ng/dl by equilibrium dialysis, Inhibin B &amp;lt; 10 pg/ml, and anti-Mullerian hormone 0.390 ng/ml. Given normal testosterone levels, he was not started on testosterone replacement. Karyotype analysis revealed 46 XX and FISH was negative for SRY gene. CT imaging of abdomen and pelvis did not reveal any Mullerian structures, prostrate and seminal vesicles reported as normal. Patient met with a Urologist and was informed that testicular sperm extraction will not be a possibility for him. Patient had a detailed consultation with a geneticist for genetic and family counseling. Chromosome microarray analysis was obtained and was normal. Invitae Disorders of sex development (DSD) panel obtained for genetic sequencing of 53 genes including SOX-9, DHH, WNT4, WT1, was found to be non-diagnostic. Conclusion and Discussion SRY negative 46 XX male is a DSD and a rare genetic cause of male factor infertility, with a discrepancy between genotype and phenotypic sex. In the case presented, genetic work up for potential etiologies has been unrevealing. Further studies are needed to identify the genetic causes of the SRY negative 46 XX male phenotype. Physicians involved in care of these patients should orient with clinical management and prognosis. For Classical 46 XX Males seeking fertility, the current options include invitro-fertilization with donor sperm or adoption only. Testosterone replacement should be considered to correct hypogonadism for physical and sexual well-being. Genetic consultation should be sought in all these cases. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Sex reversal of pejerrey (Odontesthes bonariensis), a species with temperature-dependent sex determination, in a seminatural environment.

This study examined the changes in sex ratios and sex reversal rates in pejerrey Odontesthes bonariensis that occur with the progression of the spawning season in a seminatural setting. Four groups of hatchery-produced pejerrey larvae were stocked in floating cages in La Salada de Monasterio lake (Pampas region), a natural habitat of this species, and reared from hatching beyond gonadal sex determination with minimum human interference. Cage 1 was stocked at the beginning of the spring spawning season and the other cages were stocked with monthly delays until cage 4 in early summer. The genotypic (amhy+, XY/YY; amhy-, XX) and phenotypic (testis, male; ovary, female) sex ratios and proportions of genotype/phenotype mismatched individuals were estimated and their relation to water temperature and daylength during the experiment was analysed by generalized linear modelling. Water temperature varied between 11 and 30.5°C, and daylength duration between 11 h 22 min and 14 h 35 min. Sex genotyping revealed nearly balanced sex ratios of XY/YY (46%-49.1%) and XX (50.9%-54%) fish in cages 2-4 whereas the genotypic sex ratio in cage 1 was clearly biased towards XY/YY fish (60.6%). Phenotypic males ranged from 42% to 54.4% in cages 1-3. Cage 4, in turn, had significantly more phenotypic males (66%). The percentage of XX males (phenotypic male/genotypic female) was 23.1% in cage 1, decreased to a minimum of 5.4% in cage 2 and gradually increased in cages 3 and 4 to a maximum of 40.7% in the latter. The percentages of XY/YY females (phenotypic female/genotypic male) were highest in cage 1 (30%) and decreased progressively in the other cages to a significantly lower value (4.3%) in cage 4. These results generally support the findings of laboratory studies on the effect of temperature on the sex determination of this species and also provide novel evidence of a XX genotype-specific masculinizing effect of short daylength.

Sex differences in interindividual gene expression variability across human tissues.

Understanding phenotypic sex differences has long been a goal of biology from both a medical and evolutionary perspective. Although much attention has been paid to mean differences in phenotype between the sexes, little is known about sex differences in phenotypic variability. To gain insight into sex differences in interindividual variability at the molecular level, we analyzed RNA-seq data from 43 tissues from the Genotype-Tissue Expression project (GTEx). Within each tissue, we identified genes that show sex differences in gene expression variability. We found that these sex-differentially variable (SDV) genes are associated with various important biological functions, including sex hormone response, immune response, and other signaling pathways. By analyzing single-cell RNA sequencing data collected from breast epithelial cells, we found that genes with sex differences in gene expression variability in breast tissue tend to be expressed in a cell-type-specific manner. We looked for an association between SDV expression and Graves' disease, a well-known heavily female-biased disease, and found a significant enrichment of Graves' associated genes among genes with higher variability in females in thyroid tissue. This suggests a possible role for SDV expression in sex-biased disease. We then examined the evolutionary constraints acting on genes with sex differences in variability and found that they exhibit evidence of increased selective constraint. Through analysis of sex-biased eQTL data, we found evidence that SDV expression may have a genetic basis. Finally, we propose a simple evolutionary model for the emergence of SDV expression from sex-specific constraints.

Logistic Regression With Machine Learning Sheds Light on the Problematic Sexual Behavior Phenotype.

There has been a longstanding debate about whether the mechanisms involved in problematic sexual behavior (PSB) are similar to those observed in addictive disorders, or related to impulse control or to compulsivity. The aim of this report was to contribute to this debate by investigating the association between PSB, addictive disorders (internet addiction, compulsive buying), measures associated with the construct known as reward deficiency (RDS), and obsessive-compulsive disorder (OCD). A Canadian university Office of the Registrar invited 68,846 eligible students and postdoctoral fellows. Of 4710 expressing interest in participating, 3359 completed online questionnaires, and 1801 completed the Mini-International Neuropsychiatric Interview. PSB was measured by combining those screening positive (score at least 6) on the Sexual Addiction Screening Test-Revised Core with those self-reporting PSB. Current mental health condition(s) and childhood trauma were measured by self-report. OCD was assessed by a combination of self-report and Mini-International Neuropsychiatric Interview data. Of 3341 participants, 407 (12.18%) screened positive on the Sexual Addiction Screening Test-Revised Core. On logistic regression, OCD, attention deficit, internet addiction, a family history of PSB, childhood trauma, compulsive buying, and male gender were associated with PSB. On multiple correspondence analysis, OCD appeared to cluster separately from the other measures, and the pattern of data differed by gender. In our sample, factors that have previously been associated with RDS and OCD are both associated with increased odds of PSB. The factors associated with RDS appear to contribute to a separate data cluster from OCD and to lie closer to PSB.

Characterization of the sex determining region of channel catfish (Ictalurus punctatus) and development of a sex-genotyping test

Channel catfish is an important species for aquaculture that exhibits a sexually dimorphic growth in favor of males. Genetic sexing and development of sex markers are crucial for the early identification of sex and of particular genotypes (YY males) for the production of all-male population in channel catfish aquaculture. In this study, we sequenced genomic DNA from pools of males and pools of females to better characterize the sex determining region (SDR) of channel catfish and to develop sex-specific markers for genetic sexing. Performing comparative analyses on male and female pooled genomic reads, we identified a large SDR (∼8.3 Mb) in the middle of channel catfish linkage group 4 (LG04). This non-recombining SDR contains a high-density of male-specific (Y chromosome) fixed single nucleotide polymorphisms (SNPs) along with ∼ 185 kb male-specific insertions or deletions. This SDR contains 95 annotated protein-encoding genes, including the recently reported putative channel catfish master sex determining (MSD) gene, breast cancer anti-estrogen resistance protein 1 (bcar1), located at one edge of the SDR. No sex-specific SNPs and/or indels were found in the coding sequence of bcar1, but one male-specific SNP was identified in its first intron. Based on this genomic information, we developed a PCR-based sex-specific genetic test. Genotyping results confirmed strong linkage between phenotypic sexes and the identified SDR in channel catfish. Our results confirm, using a Pool-Seq approach, that channel catfish is male heterogametic (XX-XY) with a large SDR on the LG04 sex chromosome. Furthermore, our genotyping primers can be used to identify XX, XY, and YY fish that will facilitate future research on sex determination and aquaculture applications in channel catfish.

Management challenges of disorders of sex development- Case Series

&#x0D; &#x0D; &#x0D; INTRODUCTION: Disorders of sex development (DSDs) are genetic abnormalities characterized by discordance between phenotypic, gonadal, and genetic sex. They are grouped into two categories based on karyotype: 46, XX DSD and 46, XY DSD.CASES: We reviewed two patients referred to the Rwanda Military Hospital genetic unit. The first patient was a 3-year-old toddler who was referred for confusing sex organs. Physical examination showed ambiguous genital organs with hypospadias and micropenis. Pelvic examination showed a swelling solid mass hat leading to a suspicion of ovary or undescended testes or combined ovary and testes (ovotestes). The second patient was a 17 years old teenager who presented with primary amenorrhea and lack of female secondary sexual characteristics at her age. The karyotype test was performed to investigate the genotypic sex of the patients and results revealed the karyotype formula of 46, XX/XY indicating the presence of two cell lines in the patient for the toddler and 46XYinv9 (p11q13) indicating the mismatch between the genotype and phenotype of the patients for the teenager.&#x0D; CONCLUSION: Patients were diagnosed with Disorder of Sex Development with 46, XX/XY and 46, XY genotypes respectively. A multidisciplinary team of a geneticist, urologist, endocrinologist and a psychologist reviewed the patient for the effective management.&#x0D; &#x0D; &#x0D;

A targeted metabolic analysis of football players and its association to player load: Comparison between women and men profiles.

Professional athletes undertake a variety of training programs to enhance their physical performance, technical-tactical skills, while protecting their health and well-being. Regular exercise induces widespread changes in the whole body in an extremely complex network of signaling, and evidence indicates that phenotypical sex differences influence the physiological adaptations to player load of professional athletes. Despite that there remains an underrepresentation of women in clinical studies in sports, including football. The objectives of this study were twofold: to study the association between the external load (EPTS) and urinary metabolites as a surrogate of the adaptation to training, and to assess the effect of sex on the physiological adaptations to player load in professional football players. Targeted metabolic analysis of aminoacids, and tryptophan and phenylalanine metabolites detected progressive changes in the urinary metabolome associated with the external training load in men and women’s football teams. Overrepresentation analysis and multivariate analysis of metabolic data showed significant differences of the effect of training on the metabolic profiles in the men and women teams analyzed. Collectively, our results demonstrate that the development of metabolic models of adaptation in professional football players can benefit from the separate analysis of women and men teams, providing more accurate insights into how adaptation to the external load is related to changes in the metabolic phenotypes. Furthermore, results support the use of metabolomics to understand changes in specific metabolic pathways provoked by the training process.

Y-specific amh allele, amhy, is the master sex-determining gene in Japanese flounder Paralichthys olivaceus.

Japanese flounder (Paralichthys olivaceus) is an important marine fish species of both fisheries and aquaculture in Northeast Asia. The commercial interest for all-female progenies due to several sex-related traits has prompted basic research on the mechanisms of sex determination in this species. By conducting a linkage analysis of the sex-determining locus, we initially identified 12 microsatellite markers linked to sex in 11 scaffolds, whose localization was restricted to a specific region of linkage group 9. Sequence analysis of this region identified 181 genes based on the UniProt database annotations. Among them, the amh gene was considered a potential candidate for sex determination because this gene is known to have taken over the role of sex determination in many teleosts. An in-depth sequence analysis of both the coding and non-coding regions of amh in XX and XY individuals detected nine SNPs linked with maleness. However, because these substitutions were synonymous, the upstream and downstream regions of amh were also investigated and a male-specific variant with deletions in the promoter region was detected. This truncated Y-specific amh variant was named amhy, and the amh shared by both sexes was named amhx. The association analysis using both females and males of the genotypic sex inferred by the presence/absence of amhy found complete association with phenotypic sex and genotype. Gene expression analysis in larvae derived from a single-pair progeny by quantitative real-time PCR detected amhy transcripts in the larval trunks between 20 and 100 days after hatching only in XY larvae. Localization of amhy by in situ hybridization was detected in presumptive Sertoli cells of XY gonads. Expression of amhx was almost undetectable in both XX and XY genotypes. Loss of Amh function by CRISPR-Cas9 induced male-to-female sex reversal, indicating that this gene was necessary for the masculinization of XY individuals. In conclusion, the complete linkage of amhy with males, its early expression in XY gonads before testicular differentiation, and the induction of sex reversal by loss-of-function mutation support the view that amhy is the sex-determining gene in this species.

Identification of Male-Specific Molecular Marker and Development of PCR-Based Genetic Sex Identification Technique in Spotted Knifejaw (Oplegnathus punctatus).

Spotted knifejaw (Oplegnathus punctatus) is a marine teleost species that is economically important for aquaculture and marine pasture proliferation and shows obvious bisexual growth dimorphism, but molecular sex markers are currently lacking. A 290bp (base pair) insertion with two fragments (230bp and 60bp) was identified in male individuals of O. punctatus based on whole-genome sequencing scanning and structural variation analyses. The gene annotation results showed that the insertion event occurred in the Igfn1 gene of male O. punctatus. The results of amino acid analysis further showed that the insertion event resulted in the functional variation of Igfn1 in male O. punctatus, and recombination caused the inactivation of Igfn1. According to the male-specific insertion information, we designed a PCR-based genetic amplification technique for rapid sex identification in O. punctatus. The results of agarose gel electrophoresis showed that two DNA fragments of 635bp and 925bp were amplified in male O. punctatus, while only a single DNA fragment of 635bp was amplified in female individuals. The sex of individuals identified by this method was consistent with their known phenotypic sex, which will improve sex identification efficiency. This method provides a new DNA marker for rapid sex identification in O. punctatus, which has great significance and application value in monosex breeding and provides new insights for the study of Igfn1 gene recombination and inactivation in male O. punctatus.

Изменчивость полового диморфизма размеров тела в связи с экологическими факторами в грудном периоде онтогенеза

Introduction. Dynamics of sexual dimorphism, SD, of 4 main anthropometric dimensions of 12 months old children in connection with different exogenous factors is under discussion. Materials and methods. The object of the investigation is SD variability of height, weight, chest and head girths of 12-months-old children 50 urban groups examined in 1960th-1970th are analysed. Data is borrowed from textbooks on physical development, published by Research Institute of Hygiene and Health of Children and Adolescents (1962, 1965, 1977 years). The quantitative estimation of the value of SD is based on Kullback divergence. The exogenous factors block includes different anthropogenic factors (water pollution level, air pollution, population density etc.) and climatic factors (geographical latitude of locality as characteristic of daylight duration and partly insolation level, difference between minimal and maximal year temperature values, minimal temperature of January). The estimation of direction and level of associations between somatic parameters SD and ecological factors was held using correlation analysis. Program package Statistica 10 was applied. Results. The preliminary factor analysis of considered exogenous factors extracted 4 factors, covering 79% of variability of ecological niche parameters in total. Dominant role of population size as characteristic of urban ecological niche was shown. Correlations of somatic dimensions SD of 12-months-old children with most significant ecological parameters, selected by means of factor analysis, were insignificant, but evaluation of their direction for different pairs of characteristic reveals, that for SD of height and weight associations with exogenous factors are negative, for SD of girths – are positive. Hence such body parameters as height and weight are more ecosensitive for girls, while head and chest girths for boys. The dominant role of population size characteristic in somatic variability of 1-year-old children is proved by changing of direction of correlations between SD levels and such factors as water and air pollution when megalopolises are excluded from the sample sets. Conclusion. The main result of the study is different by sex phenotype plasticity of somatic parameters in infancy. It has been revealed also that somatic status of urban samples of 1970th is associated mainly with population size.

Ageing desexualizes the Drosophila brain transcriptome.

General evolutionary theory predicts that individuals in low condition should invest less in sexual traits compared to individuals in high condition. Whether this positive association between condition and investment also holds between young (high condition) and senesced (low condition) individuals is however less clear, since elevated investment into reproduction may be beneficial when individuals approach the end of their life. To address how investment into sexual traits changes with age, we study genes with sex-biased expression in the brain, the tissue from which sexual behaviours are directed. Across two distinct populations of Drosophila melanogaster, we find that old brains display fewer sex-biased genes, and that expression of both male-biased and female-biased genes converges towards a sexually intermediate phenotype owing to changes in both sexes with age. We further find that sex-biased genes in general show heightened age-dependent expression in comparison to unbiased genes and that age-related changes in the sexual brain transcriptome are commonly larger in males than females. Our results hence show that ageing causes a desexualization of the fruit fly brain transcriptome and that this change mirrors the general prediction that low condition individuals should invest less in sexual phenotypes.

The efficacy of using pine (Pinus massoniana) pollen as an alternative to synthetic steroids in producing monosex male Nile tilapia (Oreochromis niloticus, L.)

AbstractSynthetic sex steroids are widely used to produce all‐male stocks in Nile tilapia (Oreochromis niloticus). However, there is a growing concern about the use of synthetic steroid hormones in fish as food. We investigated the efficacy of a natural sex hormone as an alternative to synthetic steroids in producing monosex male tilapia. Two‐day‐old fry were fed pine pollen powder at three different concentrations (0.5%, 1.0%, 1.5%) for 28 days and subsequently reared for 3 months to observe the efficacy of pine pollen as well as to optimize the concentration for sex reversal. As a positive control, same‐aged fry of three different commercial tilapia hatcheries were fed synthetic steroid and 17‐α‐methyl testosterone‐treated feed (60 mg/kg) for the same duration. Before analyzing the phenotypic sex, the fish were reared on untreated commercial feed for 90 days in separate tanks. The 1.0% pine pollen treatment yielded a mean of 92.50 ± 0.51% males among the progeny, higher than the mean (89.49 ± 0.25%) obtained from synthetic steroid treatments. This result demonstrates that pine pollen could be an effective compound for the direct masculinization of Nile tilapia. We also obtained a significant difference (p &lt; 0.05) in the growth performance and survival of tilapia using the dietary allotment of pine pollen. Our study suggests the feasibility of this compound as an eco‐friendly method of masculinization of tilapia and can be tried in commercial aquaculture practice.

Conservative seed fertility maintains hermaphrodites in gynodioecious Daphne jezoensis: a test of the sex-differential plasticity hypothesis.

Gynodioecy is assumed to be an evolutionary transition from hermaphroditism to dioecy. However, if hermaphrodites can better flexibly regulate seed production depending on resource availability than females, i.e. sex-differential plasticity (SDP), gynodioecy can be a stable state. In the gynodioecious shrub Daphne jezoensis, hermaphrodites generally exhibit low seed fertility and largely act as males. We examined the SDP hypothesis and the cost of fruit production to clarify why D. jezoensis did not evolve into unisexual morphs. We evaluated the size and resource dependency of reproduction in field experiments by manipulating soil nutrient and light conditions. We compared the plant size and pollen production among females, fruiting hermaphrodites and non-fruiting hermaphrodites. We then analysed the effect of current fruit production on subsequent flower production, i.e. the cost of fruit production. The fruiting ability was independent of plant size and resource availability in both sexual phenotypes, indicating the absence of SDP in D. jezoensis. Hermaphrodites produced larger-sized pollen and allocated more resources to pollen production in the non-fruiting year than in the fruiting year. In contrast, the cost of fruit production was not revealed for either sexual phenotype, even in the absence of pollen limitation, and even when fruit production was maximized. SDP could not explain the maintenance of hermaphrodites in D. jezoensis. Alternatively, the lower cost of fruit production in hermaphrodites due to their potentially low fruiting ability may hinder the evolutionary shift to dioecy.

Current and historical factors drive variation of reproductive traits in unisexual mosses in Europe: A case study

AbstractUnisexual bryophytes provide excellent models to study the mechanisms that regulate the frequency of sexual versus asexual reproduction in plants, and their ecological and evolutionary implications. Here, we determined sex expression, phenotypic sex ratio, and individual shoot traits in 242 populations of the cosmopolitan moss Pseudoscleropodium purum spanning its whole distributional range. We tested whether niche differentiation, sex‐specific differences in shoot size, and biogeographical history explained the spatial variation of reproductive traits. We observed high levels of sex expression and predominantly female‐biased populations, although both traits showed high intraspecific variation among populations. Sex expression and sex ratio were partly explained by current macroscale environmental variation, with male shoots being less frequent at the higher end of the environmental gradients defined by the current distribution of the species. Female bias in population sex ratio was significantly lower in areas recolonized after the last glacial maximum (recent populations) than in glacial refugia (long‐term persistent populations). We demonstrated that reproductive trait variation in perennial unisexual mosses is partially driven by macroscale and historical environmental variation. Based on our results, we hypothesize that sexual dimorphism in environmental tolerance and vegetative growth contribute to sex ratio bias over time, constraining the chances of sexual reproduction, especially in long‐term persistent populations. Further studies combining genetic analyses and population monitoring should improve our understanding of the implications of the intraspecific variation in the frequency of sexual versus asexual reproduction in bryophyte population fitness and eco‐evolutionary dynamics.

Characterization of sex locus and sex-specific sequences in the mandarin fishes

Sex determination of teleost fish switched frequently. Sex markers are especially practical in identifying early sex and helpful in generating mono-sex population in aquatic species. And sex determination in mandarin fishes is still unclear. In this study, we applied a pool-sequencing approach to better characterize sex-specific markers and sex determination in mandarin fishes. Using genome comparative analysis, we identified significant sex differentiated region (~5.0 Mb) and sex chromosome (LG2) in Siniperca chuatsi. Similar sex-differentiated regions were also identified on LG4 in other mandarin fishes including Siniperca knerii, Siniperca scherzeri, and Coreoperca whiteheadi. These non-recombining regions contained high-density of male-biased genetic polymorphisms accompanied with male-biased fragments (~ 23 kb in total). Meanwhile, sequence synteny analysis showed that whole genomes, including sex chromosomes and even sex-differentiated regions among these species were in good synteny. In addition, the sex-differentiated region harbored 124 genes without “usual suspects” sex determining genes. Based on this genetic information, we successfully developed male-specific genetic markers for mandarin fishes. And genotyping results showed phenotypic sexes were strongly linked to its genetic sexes in one Siniperca chuatsi population. Our results exhibited that sex-differentiated regions and sex chromosomes were relatively conserved in the four mandarin fishes. All the four mandarin fishes were identified to utilize a male heterogametic (XX-XY) sex determination system. Besides, we also developed sex-linked genetic markers. Our study will facilitate future research on sex determination and aquaculture applications in mandarin fishes.

Normative healthy reference values for global and segmental 3D principal and geometry dependent strain from cine cardiac magnetic resonance imaging.

3-Dimensional (3D) myocardial deformation analysis (3D-MDA) enables novel descriptions of geometry-independent principal strain (PS). Applied to routine 2D cine cardiovascular magnetic resonance (CMR), this provides unique measures of myocardial biomechanics for disease diagnosis and prognostication. However, healthy reference values remain undefined. This study describes age- and sex-stratified reference values from CMR-based 3D-MDA, including 3D PS. One hundred healthy volunteers were prospectively recruited following institutional ethics approval and underwent CMR imaging. 3D-MDA was performed using validated software. Age- and sex-stratified global and segmental strain measures were derived for conventional geometry-dependent [circumferential (CS), longitudinal (LS), and radial (RS)] and geometry-independent [minimum (minPS) and maximum principal (maxPS)] directions of deformation. Layer-specific contraction angle interactions were determined using local minPS vectors. The average age was 43 ± 15years and 55% were women. Strain measures were higher in women versus men. 3D PS-based assessment of maximum tissue shortening (minPS) and maximum tissue thickening (maxPS) were greater than corresponding geometry-dependent markers of LS and RS, consistent with improved representation of local tissue deformations. Global maxPS amplitude best discriminated both age and sex. Segmental analyses showed greater strain amplitudes in apical segments. Transmural PS contraction angles were higher in females and showed a heterogeneous distribution across segments. In this study we provided age and sex-based reference values for 3D strain from CMR imaging, demonstrating improved capacity for 3D PS to document maximal local tissue deformations and to discriminate age and sex phenotypes. Novel markers of layer-specific strain angles from 3D PS were also described.

Haploinsufficiency of the sex-determining genes at MATα restricts genome expansion in Saccharomyces cerevisiae

SummaryIn Saccharomyces cerevisiae, mating type of haploid cells is determined by the presence or absence of the MATα idiotype containing MATα1 and MATα2, which encode the transcription factors. These proteins are characterized by rapid turnover, but the physiological relevance of this property remains unclear. Here, we show a direct link between their intracellular levels and sexual stability. Polyploid cells with fewer MATα copies had unstable sexual phenotypes, causing morphological changes and an increase in cell death; these effects were mediated by hyperactivation of the mating pheromone response pathway. Thus, the MATα1 and MATα2 genes are haploinsufficient genes, and the reduction in their product levels causes sex fluctuation. Chromosome III harboring the mating type locus is the most prone to loss in diploids. We propose that the haploinsufficiency of MATα compensates for the drop-out prone nature of chromosome III, thereby suppressing speciation through increased genome size via polyploidization.