Cuerpos desgener[iz]ados: rescatando las experiencias de personas intersex como usuarias del sistema de salud público Chileno / Corpos desgener[iz]ados: resgatando as experiências de pessoas intersexuais como usuárias do sistema público de saúde chileno / Desgener[iz]ated bodies: rescuing the experiences of intersex people as users of the Chilean public health system

Introducción: La intersexualidad comprende condicionesinfrecuentes donde una persona nace con una anatomíasexual diferente del binario hombre-mujer; esto suponehabitar un cuerpo fuera de lo inteligible y estigmatizado.Históricamente, desde la heteronorma, el modelo biomédicoha buscado normalizarles quirúrgicamente para asignarprecoz y arbitrariamente un sexo-género armónico con lagenitalidad. Desde los Derechos Humanos, estas prácticasson cuestionadas por colectivos Intersex.Materiales y método: Estudio de caso, entre años 2019 y2020; técnica de entrevista en profundidad a dos usuariosadultos de los Policlínicos de Urología y Endocrinología de unhospital público en Santiago, Chile; se utilizó la fenomenologíade Husserl para comprender la experiencia en el sistema desalud de las personas intersex. El análisis de la informaciónse basó en la propuesta de Colaizzi.Resultados: Se reconocieron unidades de significado principalese imbricadas, cuyas esencias permitieron describir el fenómenode: ser niño y habitar el espacio hospitalario, vivir con lacondición actualmente, y la experiencia de utilizar el sistemade salud siendo adulto.Conclusiones: Se identificaron diversas estrategias de agenciatanto en el espacio hospitalario como el cotidiano, medianteun proceso personal y silencioso de aprendizajes sobre lasimplicancias de ser intersexual.(AU)

Introduction: Intersexuality includes extremely rareconditions where a person is born with a sexual anatomydifferent from the male-female binary; this supposesinhabiting a body outside the intelligible, configuringa stigma. Historically and from the heteronorm, thebiomedical model has sought to surgically normalizethem in order to precociously and arbitrarily assigna gender in harmony with genitality. From HumanRights, these practices have been questioned byIntersex groups.Materials and method: During the years 2019 and2020, case studies were carried out through in-depthinterviews with two adult users of the Urology andEndocrinology Polyclinics of a public hospital atSantiago, Chile; Husserl's phenomenology was usedto visualize the phenomenon according to how it isexperienced by the subjects who carry it, using theprocedure described by Colaizzi as an informationanalysis plan.Results: Main and overlapping units of meaning wererecognized, whose essences allowed describing thephenomenon of: being a child and inhabiting thehospital space, currently living with the condition,and the experience of using the health system as anadult, with new and own meanings.Conclusions: Various agency strategies were identifiedboth in the hospital space and in everyday life, througha personal and silent process of learning about theimplications of being intersex.(AU)

Introdução: Intersexo compreende condições rarasem que uma pessoa nasce com uma anatomia sexualdiferente do binário masculino-feminino; Isso significahabitar um corpo fora do que é inteligível e estigmatizado.Historicamente, a partir da heteronormação, o modelobiomédico buscou normalizá-los cirurgicamente paraatribuir precoce e arbitrariamente um sexo-gêneroharmônico com a genitalidade. A partir dos DireitosHumanos, essas práticas são questionadas por gruposintersexuais.Materiais e método: Estudo de caso, entre os anos de2019 e 2020; técnica de entrevista em profundidadecom dois usuários adultos das Policlínicas de Urologiae Endocrinologia de um hospital público de Santiago,Chile; A fenomenologia de Husserl foi utilizada paracompreender a experiência de pessoas intersexuaisno sistema de saúde. A análise das informações foibaseada na proposta de Colaizzi.Resultados: Reconheceram-se unidades de significadoprincipais e sobrepostas, cujas essências permitiramdescrever o fenômeno de: ser criança e habitar oespaço hospitalar, viver atualmente com a condição e aexperiência de usar o sistema de saúde na fase adulta.Conclusões: Foram identificadas várias estratégiasde agenciamento tanto no hospital como na vidaquotidiana, através de um processo pessoal e silenciosode aprendizagem sobre as implicações de ser intersexo.(AU)

Quality of Life and Psychosocial Well-Being among Intersex-Identifying Individuals in Puerto Rico: An Exploratory Study.

PURPOSE: Intersex is an umbrella term used to describe the diversity or differences in the characteristics of physical sexual development. Approximately 1.7% of the population are born intersex, and 1 in every 2000 babies at birth presents genital variation. Unfortunately, there is a lack of research on the health of intersex-identifying persons in Latin America. This study aimed to document experiences of discrimination and violence among self-identifying intersex individuals in Puerto Rico and to determine if there is a significant difference in the quality of life, psychological well-being, and social well-being between intersex-identifying and endosex individuals. METHODS: This was a quantitative method pilot study with a cross-sectional approach and exploratory comparative group design. An online survey was used, where a total of 12 self-identifying intersex adult participants were recruited, and 126 endosex adult participants served as a comparative group. RESULTS: The findings show that 83% of the participants reported experiences of discrimination and different types of violence due to their intersexuality. There was a significant difference between the intersex-identifying and endosex groups in psychological well-being, including in three of its dimensions (positives relations, autonomy, and environmental mastery). However, there were no significant differences between the groups in quality of life or social well-being. CONCLUSION: The findings of this study provide a preliminary understanding of the health disparities of intersex-identifying individuals in Puerto Rico and suggest the need for more profound research, especially the inclusion of other Caribbean and Hispanic countries. The findings also preliminarily imply the need for local and global interventions to reduce physical and mental health disparities and to improve health, quality of life, and well-being among intersex-identifying individuals.

Non-mosaic X monosomy (77,X) in a female dog with signs of virilization.

A 14-month-old female Miniature Poodle dog with an enlarged clitoris and asymmetry in the placement of the teats was subjected to clinical, histopathological, and genetic studies. Macroscopically, the uterus and fallopian tubes appeared normal, while both ovaries were diffusely altered. At histology, the ovarian parenchyma was almost completely effaced by a diffuse hyperplasia of theca cells with atretic primary follicles. Chromosome analysis showed pure (non-mosaic) X monosomy (77,X). This finding was confirmed by the highly sensitive droplet digital PCR (ddPCR) approach. Despite the observed virilization, molecular analysis did not show the presence of Y-linked genes (SRY, ZFY, and TSPY1) in the blood cells or ovary tissue. To the best of our knowledge, this is the first case of X monosomy in a dog associated with virilization.

Characterisation of eight cattle with Swyer syndrome by whole-genome sequencing.

Swyer syndrome is where an individual has the karyotype of a typical male yet is phenotypically a female. The lack of a (functional) SRY gene located on the Y-chromosome is implicated in some cases of the Swyer syndrome, although many Swyer individuals with an apparently fully functional SRY gene have also been documented. The present study undertook whole genome sequence analyses of eight cattle with suspected Swyer syndrome and compared their genome to that of both a control male and female. Sequence analyses coupled with female phenotypes confirmed that all eight individuals had the 60,XY sex reversal Swyer syndrome. Seven of the eight Swyer syndrome individuals had a deletion on the Y chromosome encompassing the SRY gene (i.e., SRY-). The eighth individual had no obvious mutation in the SRY gene (SRY+) or indeed in any reported gene associated with sex reversal in mammals; a necropsy was performed on this individual. No testicles were detected during the necropsy. Histological examination of the reproductive tract revealed an immature uterine body and horns with inactive glandular tissue of normal histological appearance; both gonads were elongated, a characteristic of most reported cases of Swyer in mammals. The flanking sequence of 11 single nucleotide polymorphisms within 10 kb of the SRY gene are provided to help diagnose some cases of Swyer syndrome. These single nucleotide polymorphisms will not, however, detect all cases of Swyer syndrome since, as evidenced from the present study (and other studies), some individuals with the Swyer condition still contain the SRY gene (i.e., SRY+).

Censoring Intersex Science: A Medical School Scandal.

A senior pediatric endocrinologist at a leading medical school in Canada has for years provided the introductory lecture on Disorders of Sex Development/Intersexuality (DSD/I) in the standard second-year course. In 2020/2021, two students complained to medical school administrators about six specific issues of intersex theory and care that were addressed in the lecture (Polychronakos, 2021). Subsequently, the administration replaced the professor with a different lecturer, thus effectively censoring the dissemination of intersex science. An overview of the status of the clinical literature on intersexuality shows that the students' critiques focus on concepts and facts that have been developed in extensive medical and sexological research over the past 50-60 years, as is shown for each of their points of critique. By censoring the professor's teaching, the medical school not only violated academic freedom, but also suppressed well-established scientific facts, kept medical students uninformed about the diverse points of view in this area of clinical management, and likely undermined future evidence-based medical and psychosocial care by these students for individuals with this type of medical condition.

Intersexual Twins due to Tetragametic Chimerism.

Disorders of or differences in sexual development (DSD) are defined by congenital conditions in which development of chromosomal, gonadal, or anatomic sex are atypical. Here, we report on monochorionic diamniotic twins delivered by caesarean section in the 36th week of pregnancy. Monochorionic twins are usually monozygous and thus should have the same sexual differentiation. In this case, one twin had female external genitalia, while the other showed ambiguous genitalia. At first, a diagnosis of mixed gonadal dysgenesis was proposed because of the obvious sexual discrepancy between the supposedly monozygous twins. Cytogenetic analyses were performed to assure the sex chromosome status for both children. Male and female cells were found subsequently in both children. While hematopoietic chimerism of monochorionic dizygous twins as a result of twin-to-twin blood transfusion is a rare but already well-documented phenomenon, to our knowledge this is the first case description of tetragametic chimerism that led to intersexuality.

XX/XY Chimerism in Internal Genitalia of a Virilized Heifer.

Five DSD heifers underwent genetic analysis in the present study. We cytogenetically analyzed in vitro cultured leukocytes and searched for SRY, AMELX/AMELY and ZFX/ZFY genes in leukocytes and hair follicles, finding that four of the studied heifers were freemartins (XX/XY leukocyte chimerism). The fifth case had an underdeveloped vulva localized ventrally and cranially to the mammary gland, a normal female sex chromosome complement (60,XX) in the leukocytes, and a lack of Y-chromosome-derived genes in the leukocytes and hair follicles. Postmortem anatomical examination of this heifer revealed the presence of normal ovaries with follicles, uterus, and oviducts, but molecular detection of the SRY, ZFX, ZFY,AMELX, and AMELY genes in these organs indicated the presence of a cell line carrying the Y chromosome. Further analysis of twelve microsatellite markers revealed the presence of additional variants at six loci in DNA samples derived from the reproductive organs; XX/XY chimerism was thus suspected in these samples. On the basis of the detection of AMELY (Y-linked) versus AMELX (X-linked) and SOX9 (autosomal) versus AMELY genes by droplet digital PCR (ddPCR), the Y/X and Y/autosome ratios were evaluated; they indicated the presence of XX and XY cell lines in the reproductive tissues. Our study showed that XX/XY chimerism can be present in the internal reproductive organs of the virilized heifers with a normal female set of sex chromosomes (60,XX) and a lack of Y-chromosome-derived genes in the leukocytes. The etiology of this phenomenon remains unknown.

What Happens When an Intersex Baby Happens.

Psychoanalytic efforts to think sexual difference beyond the restrictions of binary notions about anatomy and gender continue to prove challenging in both clinical practice and theory building. Claims that such binary notions are no longer applicable fail to take seriously the ongoing power of binary processes as they manifest both consciously and unconsciously. Without a capacity to think sexual difference as more than two, a capacity that resists the lure of spectrum modeling, efforts to conceptualize intersexuality and other nonbinary forms of anatomy and gender falter. An exploration into the challenges faced by two parents of an intersex baby, especially regarding the dilemma of pursuing genital surgery or not, shows some of the difficulties inherent in thinking sexual difference when the profound inadequacy of binary notions cannot be ignored.

The Complex and Diverse Genetic Architecture of the Absence of Horns (Polledness) in Domestic Ruminants, including Goats and Sheep.

Horns are the most obvious common feature of Bovidae. The naturally occurring absence of horns in these species, also known as polledness, is of surprisingly heterogeneous nature, although they are Mendelian traits. This review compares in detail the molecular differences among the causes of inherited polledness in the domestic ruminant species of cattle, yak, sheep, and goat based on the causal gene variants that have been discovered in recent years. The genetic causes for the lack of horns in small ruminants seem not only to be more complex, e.g., in sheep, breed-specific characteristics are still unexplained, but in goats, there is also the associated disorder of intersexuality-polled intersex syndrome (PIS). In connection with animal welfare and the associated discussion about a legal ban on the dehorning of all farm animals, naturally hornless animals and the causal genetic variants are of increasing research interest in the age of genome editing. However, the low acceptance of genetic engineering in livestock, especially in European societies, limits its use in food-producing animals. Therefore, genotype-based targeted selection of naturally occurring variants is still a widely used method for spreading this desired trait within and across populations, at least in cattle and sheep.

Whole genome sequencing identifies a missense polymorphism in PADI6 associated with testicular/ovotesticular XX disorder of sex development in dogs.

Disorders of sex development (DSDs) are congenital malformations defined as discrepancies between sex chromosomes and phenotypical sex. Testicular or ovotesticular XX DSDs are frequently observed in female dogs, while monogenic XY DSDs are less frequent. Here, we applied whole genome sequencing (WGS) to search for causative mutations in XX DSD females in French Bulldogs (FB) and American Staffordshire Terries (AST) and in XY DSD Yorkshire Terries (YT). The WGS results were validated by Sanger sequencing and ddPCR. It was shown that a missense SNP of the PADI6 gene, is significantly associated with the XX DSD (SRY-negative) phenotype in AST (P = 0.0051) and FB (P = 0.0306). On the contrary, we did not find any associated variant with XY DSD in YTs. Our study suggests that the genetic background of the XX DSD may be more complex and breed-specific.

The Timing of Genital Surgery in Somatic Intersexuality: Surveys of Patients' Preferences.

In recent years, intersex advocates, medical ethicists, and lawmakers have increasingly demanded a delay of genital surgery that is not acutely medically necessary in patients with somatic intersexuality to the age of consent. This study provides a review of published surveys of affected patients' own opinions on this issue. In part with search of PubMed 2000-2021, 10 pertinent surveys of patients were identified: 3 from the USA; 4 from European countries; and one each from Brazil, China, and Malaysia. All were based on samples of clinic patients, most of whom had previously undergone genital surgery. The majority of both XX and XY patients with somatic intersexuality favored early surgery, with somewhat more syndrome-specific variability in XY patients. The available survey data clearly indicate that a mandatory delay of genital surgery in all patients with somatic intersexuality to the age of consent would disregard the wishes of the majority of surveyed patients. A syndrome- and syndrome severity-specific individualized approach to surgery decisions appears more appropriate.

Copy number variation of the SRY gene showed an association with disorders of sex development in Yorkshire Terrier dogs.

The molecular background of disorders of sex development (DSD) in dogs is poorly understood. Several copies of the SRY genes have been reported in the dog genome. We used droplet digital PCR with the aim of determining variability in SRY copy number and its association with DSD in dogs. Altogether 19 DSD male dogs (XY DSD) of 10 breeds and 87 control dogs of eight breeds were analyzed. Moreover, we performed a comparative analysis of SRY copy number in other canids: wolves (3), red foxes (16), and Chinese raccoon dogs (10). We found that the modal number of SRY copies in dogs, wolves, red foxes, and Chinese raccoon dogs was 3, 3, 1, and 3 respectively. Variability of copy number was only observed in Yorkshire Terriers (two or three copies) and red foxes (one or two copies). An analysis of six DSD Yorkshire Terriers and 38 control males of this breed showed that 50% of the DSD dogs had two copies, while the incidence of this variant was significantly lower in the control dogs (10.5%). Searching for the copy number of the coding and 5'-flanking fragments revealed full concordance with the copy number. These fragments were also sequenced in DSD (19) and control (24) dogs, and no DNA variants were found. We conclude that, in the dog, two or three functional copies of the SRY gene are present, and a smaller number of copies showed an association with the risk of DSD phenotype in Yorkshire Terriers.

Intersex goats show different gene expression levels in the hypothalamus and pituitary compared with non-intersex goats based on RNA-Seq.

The conditions for sex reversal in vertebrate species have been extensively studied, and the results highlighted numerous key factors involved in sex differentiation. However, the transcriptomes in hypothalamic and pituitary tissues from intersex goats have rarely been studied. The aim of this study was to screen candidate genes and signalling pathways related to sex reversal in Huai goats by analyzing gene expression in hypothalamic and pituitary tissues via transcriptome sequencing and bioinformatics analyses. In total, 612 and 139 differentially expressed genes (DEGs) were identified between the intersex and non-intersex groups in the hypothalamus and pituitary, respectively. The DEGs in the hypothalamus and pituitary were significantly enriched in 41 and 16 signalling pathways, respectively, including the calcium signalling pathway, neuroactive ligand-receptor interaction signalling pathway, and oestrogen signalling pathway, which might be related to intersex sex development disorders. A candidate gene from the tachykinin family (TACR1) was significantly enriched in the calcium signalling pathway. Thirty-one DEGs were shared between these two comparisons and were enriched in several acetyl-CoA-related processes and the oestrogen signalling pathway. The results of the real-time PCR analysis show that the transcriptome sequencing results were reliable. The transcriptome data indicate that the regulation of various physiological systems is involved in intersex goat development. Therefore, these results provide helpful data enhancing our understanding of the molecular mechanisms underlying intersex syndrome in goats.

Gonadal Abnormality and Intersexuality of Oplegnathus fasciatus (Teleostei: Oplegnathidae) Collected from the Southern Coast of Korea: A Case Report.

We report on the gonadal structure abnormality and intersexuality found from a survey regarding the reproductive potential of the rock bream, Oplegnathus fasciatus, along the southern coast of Korea. In total, 448 samples were collected for histological analysis (total length 27.5±6.8 cm; total weight 522.9±385.6 g). The sex ratio (F:M) was 1:0.46 (n=307:141), with 68.5% being females. The frequency of oocyte atresia and ovarian neoplasm in the females was 85.3% and 21.5%, respectively, and the frequency of testicular lobule and cyst deformation and testicular neoplasm in the males was 73.1% and 37.6%, respectively. The scale formation in the ovary and testis was approximately 2.0% for both sexes. The intersexuality was 42.2%, with the intersexuality among females being 49.5%, which was significantly higher than that of males (26.2%). Such findings indicate a negative impact on the reproductive output of the rock bream along the southern coast of Korea; however, a more detailed study is required to ascertain accurate causes.

Parasitism-Induced Intersexuality in a Sexually Dimorphic Varunid Crab, Ptychognathus ishii (Decapoda: Varunidae).

Although many animals that perform sexual reproduction exhibit sexual dimorphism, individuals with intersex traits between the traits of males and females appear in some species, depending on environmental factors. Ptychognathus ishii, a varunid crab, exhibits distinctive sexual dimorphism in the morphology of its abdomen, chelipeds and setal tufts on the chelipeds. In this study, however, we report for the first time that intersex individuals with intermediate characters between those of males and females were occasionally found in wild populations. Morphological features of intersex individuals are described. Their taxonomic positions are identified based on DNA sequences of part of the mitochondrial cytochrome c oxidase I (COI) gene. It was shown that the intersexuality was induced by entoniscid parasites, because all intersex individuals were parasitized by entoniscid isopods, identified as Entionella sp. The apparent correlation between parasitism and morphological anomalies suggests that the parasitic isopods affect physiological conditions, leading to the feminization of male hosts.

Another lesson from beautiful monsters: the case of 'sex reversals' in the Ammonoidea and their significance.

BACKGROUND: Expression of sexual dimorphism is recognised in various fossil groups of molluscs such as the Ammonoidea, an extinct group of shelled cephalopods. During the Mesozoic, the best-documented sexual dimorphic examples are seen in the Jurassic superfamily Perisphinctoidea. It is usually expressed by distinct adult size and apertural modifications between the antidimorphs. Putative males (otherwise referred to as microconch) are small in size and develop lappets at the end of the shell while the females (macroconch) are larger and bear a simple peristome. Dubious cases are, however, known in that superfamily, which often relate to taxonomic biases or lack of diagnostic characters, and some others expose ontogenetic anomalies illustrated by 'sex reversals' in the shell morphology and ornamentation. RESULTS: The discovery of two specimens of the Callovian Aspidoceratidae Peltoceras athleta (Phillips), having both female and male features, questions the significance and causes of 'sex reversals' in the Ammonoidea. The two specimens have started with the macroconch ontogeny of Peltoceras athleta and show an apparent change toward maleness in the adult, as illustrated by their rounded whorl section, ribs retroversion, fading of the tubercles and lappets typical of the microconchs. Few other cases of female-to-male, as well as male-to-female 'sex reversal', are known in the fossil record, all belonging to the Jurassic Perisphinctoidea (families Perisphinctidae or Aspidoceratidae). Since all Jurassic Perisphinctoidea are strictly gonochoristic, these 'sex reversals' are pathological in nature and are herein referred to as a new forma-type pathology: namely "forma hermaphrodita". CONCLUSIONS: In the absence of any clear evidence of injury or parasitism, we hypothesize that such "forma hermaphrodita" individuals illustrate pathologic cases of intersexuality. Little is known about the ammonoid soft parts, and it is not possible to determine which internal sexual organs occur in specimens having both male and female external shell features. Abnormal feminisation and/or masculinisation also occur in modern cephalopods, the latter also grouping only gonochoric species. This phenomenon is similarly illustrated by a change in the adult body size and a mixing of both female and male structures. In that case, intersexuality is either advantageous in the population or caused sterility. The causes of intersexuality are not clearly established but environmental pollutants are evoked in modern cephalopods because they act as endocrine disrupters. 'Sex reversals' and/or non-functional reproductive abnormalities have also been caused by endocrine disrupters in various gonochoric gastropods species, but infestation, genetic abnormalities, temperature fluctuations or viruses are multiple causes, which can stimulate or inhibit neural-endocrinal activity by direct gonadal influence, and ultimately lead to feminisation or masculinisation in fishes, isopods, crustaceans, and gastropods as well. Regardless of whether "forma hermaphrodita" is due to an exogenic or endogenic cause, the record of intersex Perisphinctoidea in the Jurassic can be explained by the ready recognition of dimorphic pairs, and the easy collection of large and sufficiently preserved fossil palaeopopulations in which intersex specimens have statistically more chance to be found.

Chromosome abnormalities in dogs with disorders of sex development (DSD).

Disorders of sex development (DSD) caused by chromosome abnormalities are rarely diagnosed in dogs. In this report, there is a focus on five DSD cases in which the dogs had abnormal karyotypes. All animals were recognized by owners as females, however, these dogs had a large number of reproductive defects. Among these were abnormal external genitalia such as an enlarged clitoris, abnormal development of the labia, abnormal location of the vulva and urethral orifice, and other abnormalities were observed in four dogs. Gonadal histology assessments were conducted on three dogs and there were diagnoses of the presence of an ovary, inactive testes, and ovotestis with calcification in ovarian follicles. Results from cytogenetic analysis indicated there were the following karyotypes: (a) X trisomy in a mosaic form (79,XXX/78,XX); (b) Robertsonian translocation in a mosaic form (77,XX,rob/78,XX); (c) nonmosaic X/autosome translocation (78,X,t(X;A)); (d) X/autosome translocation in a mosaic form (78,X,t(X;A)/78,XX); and (e) leukocyte chimerism (78,XX/78,XY). The findings in the present study, emphasize that cytogenetic analysis is essential for elucidating the pathogenesis of DSD in dogs.

A Disorder of Sex Development in a Holstein-Friesian Heifer with a Rare Mosaicism (60,XX/90,XXY): A Genetic, Anatomical, and Histological Study.

In this study, we describe an eighteen-month-old Holstein-Friesian heifer with a deformed vulva, located abdominally. The heifer showed typical signs of estrus. A comprehensive anatomical and histopathological examination revealed a blind-ended vagina and an additional section of urethra, which became a part of the shortened penis. Cytogenetic analysis showed the presence of two cell lines: 60,XX and 90,XXY. The frequency of the triploid cell line was low (3%) in leukocytes and elevated (35%) in fibroblasts. The molecular detection of Y-linked genes (SRY and AMELY) in the blood, skin, hair follicles, and buccal epithelial cells confirmed the presence of a cell line carrying the Y chromosome. Genotyping of 16 microsatellite markers in DNA isolated from hair follicles and fibroblast culture showed the presence of one (homozygous) or two variants (heterozygous) at all the studied loci, and allowed chimerism to be excluded. We concluded that the heifer had diploid/triploid (60,XX/90,XXY) mosaicism. To our knowledge, this is only the fifth such case to be reported worldwide in this species. Since cytogenetic studies are routinely performed on in vitro cultured leukocytes, we suspect that the prevalence of this chromosome abnormality is underestimated, as it is known from published reports that the frequency of the triploid cell line is usually very low in leukocytes.

The Occurrence of Intersex in Different Populations of the Marine Amphipod Echinogammarus marinus in North-West Brittany - A Longterm-Study.

In the past two decades, an increasing body of studies has been published on the intersex phenomenon in separate-sexed crustaceans from marine and freshwater ecosystems. Various causes are being considered that could have an influence on the occurrence of intersex. Besides genetic factors, environmental conditions such as photoperiodicity, temperature, salinity and parasitism, but also environmental pollution with endocrine disrupting chemicals (EDCs) are discussed. As part of a long-term monitoring (2012 - 2020) in north-west Brittany, we recorded the occurrence of intersex in the marine amphipod Echinogammarus marinus. We quantified the intersex incidence at marine and estuarine sites and analyzed the incidence in relation to the endocrine potential of the sediments. Intersex occurred with mean frequencies between 0.87% and 12%. It was striking that the incidence of intersex increased with increasing distance from the sea. Since the highest incidence was observed at the range boundary of this stenohaline species, we assume that intersex is triggered by endocrine potential and increasing stress due to increasing freshwater content - and thus an interplay of different environmental factors.