Sex Genotype Research Articles

Gonad Transcriptome Analysis of High-Temperature-Treated Females and High-Temperature-Induced Sex-Reversed Neomales in Nile Tilapia.

Background: Nowadays, the molecular mechanisms governing TSD (temperature-dependent sex determination) or GSD + TE (genotypic sex determination + temperature effects) remain a mystery in fish. Methods: We developed three all-female families of Nile tilapia (Oreochromis niloticus), and the family with the highest male ratio after high-temperature treatment was used for transcriptome analysis. Results: First, gonadal histology analysis indicated that the histological morphology of control females (CF) was not significantly different from that of high-temperature-treated females (TF) at various development stages. However, the high-temperature treatment caused a lag of spermatogenesis in high-temperature-induced neomales (IM). Next, we sequenced the transcriptome of CF, TF, and IM Nile tilapia. 79, 11,117, and 11,000 differentially expressed genes (DEGs) were detected in the CF–TF, CF–IM, and TF–IM comparisons, respectively, and 44 DEGs showed identical expression changes in the CF–TF and CF–IM comparisons. Principal component analysis (PCA) indicated that three individuals in CF and three individuals in TF formed a cluster, and three individuals in IM formed a distinct cluster, which confirmed that the gonad transcriptome profile of TF was similar to that of CF and different from that of IM. Finally, six sex-related genes were validated by qRT-PCR. Conclusions: This study identifies a number of genes that may be involved in GSD + TE, which will be useful for investigating the molecular mechanisms of TSD or GSD + TE in fish.

Dynamics of male canine germ cell development.

Primordial germ cells (PGCs) are precursors of gametes that can generate new individuals throughout life in both males and females. Additionally, PGCs have been shown to differentiate into embryonic germ cells (EGCs) after in vitro culture. Most studies investigating germinative cells have been performed in rodents and humans but not dogs (Canis lupus familiaris). Here, we elucidated the dynamics of the expression of pluripotent (POU5F1 and NANOG), germline (DDX4, DAZL and DPPA3), and epigenetic (5mC, 5hmC, H3K27me3 and H3K9me2) markers that are important for the development of male canine germ cells during the early (22–30 days post-fertilization (dpf)), middle (35–40 dpf) and late (45–50 dpf) gestational periods. We performed sex genotype characterization, immunofluorescence, immunohistochemistry, and quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) analyses. Furthermore, in a preliminary study, we evaluated the capacity of canine embryo PGCs (30 dpf) to differentiate into EGCs. To confirm the canine EGCs phenotype, we performed alkaline phosphatase detection, immunohistochemistry, electron and transmission scanning microscopy and RT-qPCR analyses. The PGCs were positive for POU5F1 and H3K27me3 during all assessed developmental periods, including all periods between the gonadal tissue stage and foetal testes development. The number of NANOG, DDX4, DAZL, DPPA3 and 5mC-positive cells increased along with the developing cords from 35–50 dpf. Moreover, our results demonstrate the feasibility of inducing canine PGCs into putative EGCs that present pluripotent markers, such as POU5F1 and the NANOG gene, and exhibit reduced expression of germinative genes and increased expression of H3K27me3. This study provides new insight into male germ cell development mechanisms in dogs.

Origin and transition of sex determination mechanisms in a gynogenetic hexaploid fish.

Most vertebrates reproduce sexually, and plastic sex determination mechanisms including genotypic sex determination (GSD) and environmental sex determination (ESD) have been extensively revealed. However, why sex determination mechanisms evolve diversely and how they correlate with diverse reproduction strategies remain largely unclear. Here, we utilize the superiority of a hexaploid gibel carp (Carassius gibelio) that is able to reproduce by unisexual gynogenesis and contains a rare but diverse proportion of males to investigate these puzzles. A total of 2248 hexaploid specimens were collected from 34 geographic wild populations throughout mainland China, in which 24 populations were revealed to contain 186 males with various incidences ranging from 1.2 to 26.5%. Subsequently, the proportion of temperature-dependent sex determination (TSD) was revealed to be positively correlated to average annual temperature in wild populations, and male incidence in lab gynogenetic progenies was demonstrated to increase with the increasing of larval rearing temperature. Meanwhile, extra microchromosomes were confirmed to play genotypic male determination role as previously reported. Thereby, GSD and TSD were found to coexist in gibel carp, and the proportions of GSD were observed to be much higher than that of TSD in sympatric wild populations. Our findings uncover a potential new mechanism in the evolution of sex determination system in polyploid vertebrates with unisexual gynogenesis ability, and also reveal a possible association of sex determination mechanism transition between TSD and GSD and reproduction mode transition between unisexual gynogenesis and bisexual reproduction.

Identification of the sex-determining locus in grass puffer (Takifugu niphobles) provides evidence for sex-chromosome turnover in a subset of Takifugu species.

There is increasing evidence for frequent turnover in sex chromosomes in vertebrates. Yet experimental systems suitable for tracing the detailed process of turnover are rare. In theory, homologous turnover is possible if the new sex-determining locus is established on the existing sex-chromosome. However, there is no empirical evidence for such an event. The genus Takifugu includes fugu (Takifugu rubripes) and its two closely-related species whose sex is most likely determined by a SNP at the Amhr2 locus. In these species, males are heterozygous, with G and C alleles at the SNP site, while females are homozygous for the C allele. To determine if a shift in the sex-determining locus occurred in another member of this genus, we used genetic mapping to characterize the sex-chromosome systems of Takifugu niphobles. We found that the G allele of Amhr2 is absent in T. niphobles. Nevertheless, our initial mapping suggests a linkage between the phenotypic sex and the chromosome 19, which harbors the Amhr2 locus. Subsequent high-resolution analysis using a sex-reversed fish demonstrated that the sex-determining locus maps to the proximal end of chromosome 19, far from the Amhr2 locus. Thus, it is likely that homologous turnover involving these species has occurred. The data also showed that there is a male-specific reduction of recombination around the sex-determining locus. Nevertheless, no evidence for sex-chromosome differentiation was detected: the reduced recombination depended on phenotypic sex rather than genotypic sex; no X- or Y-specific maker was obtained; the YY individual was viable. Furthermore, fine-scale mapping narrowed down the new sex-determining locus to the interval corresponding to approximately 300-kb of sequence in the fugu genome. Thus, T. niphobles is determined to have a young and small sex-determining region that is suitable for studying an early phase of sex-chromosome evolution and the mechanisms underlying turnover of sex chromosome.

Bayesian informed evidence against modulation of androstadienone-effects by genotypic receptor variants and participant sex: A study assessing Stroop interference control, mood and olfaction

The androgen derivative androstadienone (AND) is present in human sweat and may act as human chemosignal. Though effects of AND have been reported with respect to emotional and cognitive processes, results have been highly inconsistent. For this reason, it is likely that AND-action is dependent on modulatory factors. Here we wanted to specifically investigate the impact of genotypic variations of the AND-receptor OR7D4, as well as the influence of participant sex and concomitant hormonal fluctuations on AND-action during emotional interference processing, olfactory performance and mood assessments.To this end 80 healthy individuals (women taking oral contraceptives; naturally cycling women measured during the luteal phase and men) were tested twice on two consecutive days (AND vs. placebo exposure) with an emotional Stroop task. Also, olfactory performance and mood was assessed. Participants provided saliva samples to measure testosterone, progesterone and estradiol and a blood sample to assess genotypic variations of the AND-receptor OR7D4.We found a small task-dependent reduction of overall error rates under AND but no modulation of effects by genetic variation or group (female OC, female NC, male) with respect to olfactory performance and mood. Additional analyses with help of Bayesian statistics gave strong evidence in favor of specific null hypotheses suggesting that the action of AND was not modulated by either genotypic variations or sex of participants with respect to interference control (bias indices), olfactory self-reports and mood parameters.Additional effects of AND in connection with hormonal fluctuations are reported.

X- and Y-chromosome-specific variants of the amelogenin gene allow non-invasive sex diagnosis for the detection of pseudohermaphrodite goats.

The Polled Intersex Syndrome (PIS) is responsible for the absence of horns in homozygous and heterozygous goats causing a female-to-male sex reversal in the homozygous polled genotypic female (XX) goats. A simple and efficient non-invasive method was elaborated to detect the genotypic sex from hair and faecal samples using a pair of primers to amplify the X- and Y-linked alleles of the amelogenin gene. The PCR products were easily distinguishable using agarose gel electrophoresis: we detected an X-specific single band in samples originating from healthy phenotypic females and double (X- and Y-) bands in samples from males. The new PCR method is applicable for diagnosing the sex of PIS-affected animals already as newborn kids, in contrast with the phenotypic findings appearing only after puberty, and thus it may replace the cumbersome chromosome investigations.

Putative Independent Evolutionary Reversals from Genotypic to Temperature-Dependent Sex Determination are Associated with Accelerated Evolution of Sex-Determining Genes in Turtles.

The evolutionary lability of sex-determining mechanisms across the tree of life is well recognized, yet the extent of molecular changes that accompany these repeated transitions remain obscure. Most turtles retain the ancestral temperature-dependent sex determination (TSD) from which multiple transitions to genotypic sex determination (GSD) occurred independently, and two contrasting hypotheses posit the existence or absence of reversals back to TSD. Here we examined the molecular evolution of the coding regions of a set of gene regulators involved in gonadal development in turtles and several other vertebrates. We found slower molecular evolution in turtles and crocodilians compared to other vertebrates, but an acceleration in Trionychia turtles and at some phylogenetic branches demarcating major taxonomic diversification events. Of all gene classes examined, hormone signaling genes, and Srd5a1 in particular, evolve faster in many lineages and especially in turtles. Our data show that sex-linked genes do not follow a ubiquitous nor uniform pattern of molecular evolution. We then evaluated turtle nucleotide and protein evolution under two evolutionary hypotheses with or without GSD-to-TSD reversals, and found that when GSD-to-TSD reversals are considered, all transitional branches irrespective of direction, exhibit accelerated molecular evolution of nucleotide sequences, while GSD-to-TSD transitional branches also show acceleration in protein evolution. Significant changes in predicted secondary structure that may affect protein function were identified in three genes that exhibited hastened evolution in turtles compared to other vertebrates or in transitional versus non-transitional branches within turtles, rendering them candidates for a key role during SDM evolution in turtles.

Sex determination mode does not affect body or genital development of the central bearded dragon (Pogona vitticeps)

BackgroundThe development of male- or female-specific phenotypes in squamates is typically controlled by either temperature-dependent sex determination (TSD) or chromosome-based genetic sex determination (GSD). However, while sex determination is a major switch in individual phenotypic development, it is unknownhow evolutionary transitions between GSD and TSD might impact on the evolution of squamate phenotypes, particularly the fast-evolving and diverse genitalia. Here, we take the unique opportunity of studying the impact of both sex determination mechanisms on the embryological development of the central bearded dragon (Pogona vitticeps). This is possible because of the transitional sex determination system of this species, in which genetically male individuals reverse sex at high incubation temperatures. This can trigger the evolutionary transition of GSD to TSD in a single generation, making P. vitticeps an ideal model organism for comparing the effects of both sex determination processes in the same species.ResultsWe conducted four incubation experiments on 265 P. vitticeps eggs, covering two temperature regimes (“normal” at 28 °C and “sex reversing” at 36 °C) and the two maternal sexual genotypes (concordant ZW females or sex-reversed ZZ females). From this, we provide the first detailed staging system for the species, with a focus on genital and limb development. This was augmented by a new sex chromosome identification methodology for P. vitticeps that is non-destructive to the embryo. We found a strong correlation between embryo age and embryo stage. Aside from faster growth in 36 °C treatments, body and external genital development was entirely unperturbed by temperature, sex reversal or maternal sexual genotype. Unexpectedly, all females developed hemipenes (the genital phenotype of adult male P. vitticeps), which regress close to hatching.ConclusionsThe tight correlation between embryo age and embryo stage allows the precise targeting of specific developmental periods in the emerging field of molecular research on P. vitticeps. The stability of genital development in all treatments suggests that the two sex-determining mechanisms have little impact on genital evolution, despite their known role in triggering genital development. Hemipenis retention in developing female P. vitticeps, together with frequent occurrences of hemipenis-like structures during development in other squamate species, raises the possibility of a bias towards hemipenis formation in the ancestral developmental programme for squamate genitalia.

Hormonal and thermal induction of sex reversal in the bearded dragon (Pogona vitticeps, Agamidae)

In amniotes (mammals, reptiles and birds) we can find two major sex-determining modes: environmental sex determination (ESD), largely in the form of temperature-dependent sex determination, and genotypic sex determination (GSD). It is evident that in reptiles there were multiple transitions between these two modes, but their directions are often difficult to reconstruct. However, it seems that GSD to ESD transitions were much less frequent. Such a transition demands production of sex-reversed individuals, i.e. individuals with a mismatch between gonadal and genotypic sex, which have to be viable and fertile in spite of lacking sex-specific parts of genomes linked to Y or W chromosomes. Up to now, there is only a single well-documented transition from the ancestral GSD to ESD among amniotes: a laboratory experiment with the bearded dragon, Pogona vitticeps. The gonadal females with male-typical ZZ genotype induced by high incubation temperatures in this species possessed masculinized morphology and behaviour. However, it is not clear whether these masculinized phenotypic traits can be attributed to the lack of female-specific W chromosome, or to extreme incubation temperatures. In this contribution, we describe the results of the experiments aiming to develop a system allowing disentangling the effects of temperature and genotype by hormonal manipulations, specifically by the application of fadrozole and exogenous estradiol (E2) to developing eggs in a captive bred population of the bearded dragon. We documented that both high incubation temperature and E2 application at normal incubation temperature can induce development of ZZ sex-reversed females in this laboratory population and that these females are able to lay eggs. On the other hand, the application of fadrozole led either to high hatchling mortality or to development of individuals with enlarged hemipenes, but did not induce sex reversal. The developed system will be useful in future studies to fully utilize the very valuable bearded dragon model for general understanding of potential limits and constraints of GSD to ESD transitions.

Chromosomal Context Affects the Molecular Evolution of Sex-linked Genes and Their Autosomal Counterparts in Turtles and Other Vertebrates.

Sex chromosomes evolve differently from autosomes because natural selection acts distinctly on them given their reduced recombination and smaller population size. Various studies of sex-linked genes compared with different autosomal genes within species support these predictions. Here, we take a novel alternative approach by comparing the rate of evolution between subsets of genes that are sex-linked in selected reptiles/vertebrates and the same genes located in autosomes in other amniotes. We report for the first time the faster evolution of Z-linked genes in a turtle (the Chinese softshell turtle Pelodiscus sinensis) relative to autosomal orthologs in other taxa, including turtles with temperature-dependent sex determination (TSD). This faster rate was absent in its close relative, the spiny softshell turtle (Apalone spinifera), thus revealing important lineage effects, and was only surpassed by mammalian-X linked genes. In contrast, we found slower evolution of X-linked genes in the musk turtle Staurotypus triporcatus (XX/XY) and homologous Z-linked chicken genes. TSD lineages displayed overall faster sequence evolution than taxa with genotypic sex determination (GSD), ruling out global effects of GSD on molecular evolution beyond those by sex-linkage. Notably, results revealed a putative selective sweep around two turtle genes involved in vertebrate gonadogenesis (Pelodiscus-Z-linked Nf2 and Chrysemys-autosomal Tspan7). Our observations reveal important evolutionary changes at the gene level mediated by chromosomal context in turtles despite their low overall evolutionary rate and illuminate sex chromosome evolution by empirically testing expectations from theoretical models. Genome-wide analyses are warranted to test the generality and prevalence of the observed patterns.

Hybridization and heterosis in the Plicatula group of Paspalum

Most forage cultivars released for the genus Paspalum belong to a section named Plicatula. The species of Plicatula are mostly apomictic and consequently the genetic diversity is locked for their genetic improvement. The objectives were to evaluate the crossability, hybrid fertility, heterosis, and genetic distances between apomictic accessions and a sexual genotype of species of Plicatula group of Paspalum. Crosses were made using 22 apomictic tetraploid accessions belonging to 12 different species as pollen donors, and a sexual tetraploid genotype induced by colchicine from a sexual diploid accession of P. plicatulum. Crossability varied between 0 and 16% among crosses. Viable hybrid offspring were recovered from 15 out of 22 crosses. The most successful crosses involved P. guenoarum, P. plicatulum, P. chaseanum, and P. oteroi. Fertility of the sampled hybrids varied between 1.6% for the cross involving P. lenticulare, and 40.1% for an intraspecific cross (P. plicatulum, accession Hojs388). The genetic distance between parents was estimated using amplified fragment-length polymorphism, and it varied between 0.34 and 0.53. There was no correlation between genetic distances and crossability or fertility of the hybrids. Hybrids from the most numerous families were classified for mode of reproduction using flow cytometric seed analysis. The ratio between sexual and apomictic hybrids varied between 0.6:1 and 1.6:1. A selected group of apomictic hybrids were evaluated for several agronomic traits in the field. Heterosis was observed for frost tolerance and cattle preference. The results indicated that gene transfer via hybridization is possible among several species of Plicatula. Superior hybrids for specific traits can be generated and fixed by apomixis.

A Duplicated, Truncated amh Gene Is Involved in Male Sex Determination in an Old World Silverside.

A master sex-determining gene, the Y chromosome-linked anti-Müllerian hormone (amhy) gene, has been described in two New World atheriniform species but little is known on the distribution, evolution, and function(s) of this gene in other Atheriniformes. Interestingly, amhy has been found to coexist with temperature-dependent sex determination (TSD), providing a unique opportunity to explore the interplay between genotypic and environmental sex determination. In this study, the search for an amhy homolog was extended to an Old World atheriniform, the cobaltcap silverside Hypoatherina tsurugae (Atherinidae). The full sequences, including the coding and noncoding regions, of the autosomal amh (amha) and a putative amhy were obtained. The deduced Amha and Amhy proteins comprised 511 and 340 amino acids (aa), respectively. PCR analysis with genomic DNA from wild adults and from laboratory-reared juveniles revealed a high, but not complete association of ∼95% between amhy and maleness. The spatiotemporal expression of amhy and amha during gonadal sex differentiation was analyzed by qRT-PCR and in situ hybridization (ISH). amhy transcription (in amhy-positive larvae) started before and peaked during histological differentiation of the gonads whereas amha was negligible during the same period in both genotypes. These results demonstrate that the amhy, although with some structural differences in relation to the amhy of some New World atheriniforms, is strongly associated with maleness and probably important for testicular development in this Old World atheriniform. Thus, amhy is a candidate sex determination gene in cobaltcap silverside and it will be key to scrutinize the mechanism of sex determination in this species.

Climate-driven shifts in adult sex ratios via sex reversals: the type of sex determination matters.

Sex reversals whereby individuals of one genetic sex develop the phenotype of the opposite sex occur in ectothermic vertebrates with genetic sex-determination systems that are sensitive to extreme temperatures during sexual differentiation. Recent rises in global temperatures have led researchers to predict that sex reversals will become more common, resulting in the distortion of many populations' sex ratios. However, it is unclear whether susceptibility to climate-driven sex-ratio shifts depends on the type of sex determination that varies across species. First, we show here using individual-based theoretical models that XX/XY (male-heterogametic) and ZZ/ZW (female-heterogametic) sex-determination systems can respond differentially to temperature-induced sex reversals. Interestingly, the impacts of climate warming on adult sex ratio (ASR) depend on the effects of both genotypic and phenotypic sex on survival and reproduction. Second, we analyse the temporal changes of ASR in natural amphibian populations using data from the literature, and find that ASR shifted towards males in ZZ/ZW species over the past 60 years, but did not change significantly in XX/XY species. Our results highlight the fact that we need a better understanding of the interactions between genetic and environmental sex-determining mechanisms to predict the responses of ectotherms to climate change and the associated extinction risks.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.

IMPACT OF APOE GENOTYPE ON THE SEX-DIFFERENTIATED BIOENERGETIC TRAJECTORIES AND AD RISKS IN AGING MOUSE BRAINS

Age, APOE4 genotype, and female sex are top risk factors for AD. Our previous studies demonstrated that the bioenergetic shifts occurring in the perimenopausal female brain could contribute to an increased AD risk in women. We also observed substantial sex disparities in brain bioenergetic trajectories in normal aging mice. The goal of this study is to determine the sex differences in the impact of APOE genotype on AD at-risk phenotypes during brain aging. Female and male, APOE3- and APOE4 targeted replacement (TR) mice were assessed for: (a) bioenergetic-, inflammatory-, and AD pathology-related gene expression in hippocampus followed by bioinformatic analysis, and (b) key metabolic parameters in the periphery. Functional assessments are undergoing, including: (a) FDG-microPET for cerebral glucose metabolism, (b) brain mitochondrial function, and (c) glucose tolerance test for peripheral metabolism. Gene expression analyses revealed that female APOE4 mice at pre-menopause age (6-month old) exhibited a significantly different bioenergetic profile relative to APOE3 controls: APOE4 mice showed a higher expression of genes involved in mitochondrial oxidative phosphorylation, mitochondrial membrane transport, and mitochondrial fusion. These changes in female APOE4 brains could represent an adaptive response to deficits in brain glucose availability and a shift in energy fuels from glucose to ketone bodies and glucose. This hypothesis is further supported by: (a) APOE4 mice had lower levels of plasma glucose in both sexes while the higher levels of ketone bodies and triglycerides were only seen in the females; (b) both APOE3 and APOE4 females had lower peripheral glucose levels and higher ketone body levels than their genotype-matched male counterparts, indicating a potential earlier shift in bioenergetic fuel usage in females. These findings suggest that APOE4 genotype interacts with the age-related decline in glucose metabolism and the bioenergetic shift to alternative fuels, particularly in females. Outcomes of this study will provide mechanistic details of the APOE4 genetic burden on the sex-differentiated bioenergetic fluctuation during aging and its contribution to higher AD risks in women. This work was supported by NIA 5P01AG026572 to RDB and Alzheimer's Association SAGA-17–419459 to RDB.

Epigenetic control of cyp19a1a expression is critical for high temperature induced Nile tilapia masculinization

In fish species with temperature-dependent sex determination (TSD) or genotypic sex determination plus temperature effects (GSD + TE), temperature can either affect sex differentiation or determine the sex. However, it is unknown if epigenetic control of cyp19a1a expression is critical for high temperature induced masculinization in the freshwater fish Nile tilapia. We analyzed the cyp19a1a DNA methylation levels in three age groups and found that they were lower in females than in males. At 8 months of age, males had DNA methylation levels of the cyp19a1a promoter that were almost twice as high as those of females. Exposure to high temperatures increased the cyp19a1a promoter DNA methylation levels from 30.87 ± 4.56% to 48.34 ± 0.92% (P = 0.035) in females and from 50.33 ± 7.38% to 51.66 ± 4.75% in males (P = 0.867). The increases in the cyp19a1a promoter DNA methylation levels were associated with the mRNA expression levels and might play a role in promoting gonadal differentiation in high temperature induced group females toward the male pathway. Western blot analysis revealed that the cyp19a1a protein expression levels in females significantly declined after high temperature treatment; only a slight decline was recorded in male fish. These results reveal that epigenetic control of cyp19a1a mRNA and protein expression is related to the environmental temperature and sex ratios in fish with TSD or GSD + TE.

Incubation Temperature Modifies Sex Ratio of Hatchlings in Collared Lizards, Crotaphytus collaris

Abstract Increasing evidence indicates that sex-determination mechanisms in reptiles (genotypic sex determination [GSD] and temperature-dependent sex determination [TSD]) are considerably labile and not mutually exclusive. Environmental factors can override GSD in some reptile species and some species shift from GSD to TSD at certain temperatures. We present data on the effects of incubation temperature on sex ratio in Collared Lizard (Crotaphytus collaris) hatchlings. Eggs were incubated at one of seven constant temperatures. More males were produced at both lower and higher temperatures and more females at intermediate temperatures. Although none of the seven treatments produced only females or only males (nor even differed significantly from an equal sex ratio), incubation at different constant temperatures influenced hatchling sex ratios and produced an overall statistically significant pattern, consistent with TSD pattern II but in an inverse way. Even with a lack of evidence, GSD has been suggested ...

Establishment of monosex female production of sablefish (Anoplopoma fimbria) through direct and indirect sex control

Methods are needed for monosex production of sablefish (Anoplopoma fimbria) to capitalize on superior growth of females relative to males. This study aimed to characterize the system of sex determination and establish methods for both direct and indirect feminization of sablefish. Juvenile sablefish ~40mm fork length were fed diets containing 17β-estradiol (E2), 17α-methyltestosterone (MT), or ethanol vehicle alone (control) for 2months and then divided into subgroups either shifted to the control diet (E2- and MT-short (S) duration treatments) or maintained on steroid-treated diets for an additional 2months (E2- and MT-long (L) duration treatments). Fish were subsampled for gonadal histology at the midpoint and end of the dietary treatments and all remaining fish were individually tagged to monitor subsequent growth and gonadal development for 36months (post-treatment time points of 0, 4, 16, 24, and 36months). Control fish exhibited balanced (1:1) sex ratios. E2 treatment regardless of duration induced ovarian differentiation in 100% of the genotypic males (i.e., direct feminization), while only the MT-L treatment induced testicular differentiation in 100% of the genotypic females (i.e., generating “neomales”). A high proportion (89%) of MT-S genotypic females possessed intersex gonads, indicating short-term MT exposure was insufficient to induce complete sex reversal. Significant differences in sex-specific growth were apparent by 16months post-treatment and associated with gonadal phenotype; sablefish with ovaries outgrew those with testes, regardless of genotypic sex. Fish from the E2-S and -L and MT-L treatment groups maintained their respective feminized and masculinized states after steroid withdrawal, although MT-S treated genotypic females tended to show further masculinization post-treatment. Upon reaching sexual maturity, control males and neomales were crossed with wild-caught female broodstock. Resultant embryos from control crosses were 54.6±8.9% (mean±SD) genotypic female, while those from neomale-female crosses were 100±0.0% genotypic female. Following sex differentiation, gonadal histology demonstrated that offspring from control crosses had a balanced phenotypic sex ratio, whereas all neomale offspring developed normal ovaries. This study establishes that sablefish utilize an XX/XY system of sex determination and methods for both direct and indirect monosex female production.

Clinical characteristics of melanoma in an ethnically diverse population of adolescents and young adults.

e21043 Background: Melanoma is the third most common cancer among adolescents and young adults (AYAs; aged 15-39). Disease characteristics have not been well-described in this age group, particularly among diverse populations. We describe clinical features of AYAs diagnosed with melanoma at a large public hospital serving an ethnically diverse population. Methods: We reviewed medical chart data from patients diagnosed with melanoma between 2001-2016 at Los Angeles County + USC Medical Center. We describe clinical characteristics of AYA patients and compare to non-AYAs (aged ≥40) using Fisher’s exact test. A p-value < 0.05 was considered statistically significant. Results: Of the 273 melanoma patients identified, 47 (17.3%) were AYAs (mean age 32.3; SD±4.45; lower age range 18). The majority of patients were Hispanic (AYA, 53.2%; non-AYA, 51.1%), followed by non-Hispanic whites (AYA, 38.3%; non-AYA, 38.7%). A greater proportion of AYA patients were female (59.6%) compared to non-AYAs (38.2%) (p < 0.01). No AYA patients reported prior skin cancer compared to 19.9% of non-AYAs; 8.5% of AYAs reported family history of melanoma compared to 6.3% of non-AYAs. For all patients, superficial spreading melanoma was the most common histological subtype (AYA, 21.3%; non-AYA, 20.9%). Nodular melanoma was the second most common subtype in AYAs (17.02%) in contrast to acral lentiginous melanoma among non-AYAs (20.9%). Median Breslow depth was 3.0 mm for AYAs and 2.55 mm among non-AYAs. A slightly higher percentage of AYAs were diagnosed with regional disease (31.9%) than non-AYAs (24.4%), and a greater proportion of non-AYAs presented with distant metastases (AYA, 6.4%; non-AYA, 18.7%). The most common site of diagnosis were the extremities for all patients (AYA, 45.0%; non-AYA, 29.3%). Conclusions: We found similar clinical characteristics between AYA and non-AYA melanoma patients. However, we found a statistically significant difference for gender. The increased incidence of melanoma in female AYAs may be driven by biological factors such as sex hormones or genotype, or tanning behaviors. Further research is warranted to identify predictive and prognostic factors of melanoma among diverse AYAs, particularly females.

Female phenotype with male karyotype: a clinical enigma

Development of gonadal and phenotypic sex during embryogenesis invariably corresponds to the genotypic sex. However, some disorders of sex development are associated with discordance between the chromosomal, gonadal or phenotypic...

Assessment of cardiac function in children with congenital adrenal hyperplasia: a case control study in Cameroon

BackgroundHigh level of androgens found in congenital adrenal hyperplasia (CAH) seems to have a deleterious effect on heart function. We therefore evaluate cardiac function of children with CAH in comparison with a healthy group.MethodsWe carried out a case-control study in the single endocrinology unit of the Mother and Child Center of Chantal Biya’s Foundation. Cases were matched for age and genotypic sex to 2 healthy controls. We analyzed the ejection fraction (LVEF), fractional shortening and left ventricular mass; output and cardiac index; E and A waves velocities, E/A ratio and the mitral deceleration time and diameter of the left atrium; tricuspid annular plane systolic excursion and pulmonary artery systolic pressure were also measured.ResultsWe included 19 patients with a median age of 6.26 ± 3.75 years and 38 controls stackable distribution. The left ventricular mass of cases was greater than that of controls. A case of reversible cardiomyopathy on hormone replacement therapy was found.For the cases, the average ejection fraction was 71.95 ± 7.88%; the average fractional shortening was 40.67 ± 7.02%. All these values ​​were higher than those of controls, although the difference was not statistically significant. Diastolic left ventricular function was more impaired among the cases.Right ventricular function was similar in both groups. These abnormalities were highly correlated to the late age at diagnosis and duration of treatment.ConclusionThis study shows an altered cardiac function in CAH compared to healthy control and highlights importance of an early diagnosis of cases, a tight control of androgens levels and a regular monitoring of cardiac function.