Studies on sex differentiation and sex determination in amphibians. II. Sex reversal in female tadpoles of Rana sylvatica following the application of high temperature

1929 ◽  
Vol 52 (2) ◽  
pp. 267-291 ◽  
Author(s):  
Emil Witschi
Keyword(s):  
High Temperature ◽  
Sex Determination ◽  
Sex Differentiation ◽  
Rana Sylvatica ◽  
Sex Reversal

scholarly journals Sex Ratios in a Warming World: Thermal Effects on Sex-Biased Survival, Sex Determination, and Sex Reversal

2021 ◽  
Vol 112 (2) ◽  
pp. 155-164
Author(s):  
Suzanne Edmands
Keyword(s):  
High Temperature ◽  
Sex Ratio ◽  
Sex Determination ◽  
Heat Tolerance ◽  
Sex Ratios ◽  
Sex Reversal ◽  
Survival Sex ◽  
Ratio Distortion ◽  
Warming World ◽  
Sex Ratio Distortion

Abstract Rising global temperatures threaten to disrupt population sex ratios, which can in turn cause mate shortages, reduce population growth and adaptive potential, and increase extinction risk, particularly when ratios are male biased. Sex ratio distortion can then have cascading effects across other species and even ecosystems. Our understanding of the problem is limited by how often studies measure temperature effects in both sexes. To address this, the current review surveyed 194 published studies of heat tolerance, finding that the majority did not even mention the sex of the individuals used, with <10% reporting results for males and females separately. Although the data are incomplete, this review assessed phylogenetic patterns of thermally induced sex ratio bias for 3 different mechanisms: sex-biased heat tolerance, temperature-dependent sex determination (TSD), and temperature-induced sex reversal. For sex-biased heat tolerance, documented examples span a large taxonomic range including arthropods, chordates, protists, and plants. Here, superior heat tolerance is more common in females than males, but the direction of tolerance appears to be phylogenetically fluid, perhaps due to the large number of contributing factors. For TSD, well-documented examples are limited to reptiles, where high temperature usually favors females, and fishes, where high temperature consistently favors males. For temperature-induced sex reversal, unambiguous cases are again limited to vertebrates, and high temperature usually favors males in fishes and amphibians, with mixed effects in reptiles. There is urgent need for further work on the full taxonomic extent of temperature-induced sex ratio distortion, including joint effects of the multiple contributing mechanisms.

scholarly journals The Role of Anti-Müllerian Hormone in Testis Differentiation Reveals the Significance of the TGF-β Pathway in Reptilian Sex Determination

Genetics ◽  
2019 ◽  
Vol 213 (4) ◽  
pp. 1317-1327 ◽  
Author(s):  
Yingjie Zhou ◽  
Wei Sun ◽  
Han Cai ◽  
Haisheng Bao ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Sex Determination ◽  
Messenger Rna ◽  
Sex Differentiation ◽  
Sex Reversal ◽  
Testicular Development ◽  
Loss Of Function ◽  
Specific Expression ◽  
Male Sex ◽  
Specific Expression Pattern ◽  
Reptilian Species

Anti-Müllerian hormone (Amh, or Müllerian-inhibiting substance, Mis), a member of TGF-β superfamily, has been well documented in some vertebrates as initiator or key regulator in sexual development, and particularly in fish. However, its functional role has not yet been identified in reptiles. Here, we characterized the Amh gene in the Chinese soft-shelled turtle Pelodiscus sinensis, a typical reptilian species exhibiting ZZ/ZW sex chromosomes. The messenger RNA of Amh was initially expressed in male embryonic gonads by stage 15, preceding gonadal sex differentiation, and exhibited a male-specific expression pattern throughout embryogenesis. Moreover, Amh was rapidly upregulated during female-to-male sex reversal induced by aromatase inhibitor letrozole. Most importantly, Amh loss of function by RNA interference led to complete feminization of genetic male (ZZ) gonads, suppression of the testicular marker Sox9, and upregulation of the ovarian regulator Cyp19a1. Conversely, overexpression of Amh in ZW embryos resulted in female-to-male sex reversal, characterized by the formation of a testis structure, ectopic activation of Sox9, and a remarkable decline in Cyp19a1. Collectively, these findings provide the first solid evidence that Amh is both necessary and sufficient to drive testicular development in a reptilian species, P. sinensis, highlighting the significance of the TGF-β pathway in reptilian sex determination.

Cyp17a1 is required for female sex determination and male fertility by regulating sex steroid biosynthesis in fish

Endocrinology ◽  
2021 ◽  
Author(s):  
Lanying Yang ◽  
Xuefeng Zhang ◽  
Shujun Liu ◽  
Chenhua Zhao ◽  
Yiyang Miao ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Differentiation ◽  
Ectopic Expression ◽  
Sex Reversal ◽  
Mitochondrial Morphology ◽  
Critical Window ◽  
Female Sex ◽  
Estrogen Production ◽  
Endogenous Estrogen ◽  
Cytochrome P450 Family

Abstract In teleost fish, sex steroids are involved in sex determination, sex differentiation, and fertility. Particularly, Cyp17a1 (Cytochrome P450 family 17 subfamily A member 1) is thought to play essential roles in fish steroidogenesis. Therefore, to further understand its roles in steroidogenesis, sex determination, and fertility in fish, we constructed a cyp17a1 gene mutant in Nile tilapia (Oreochromis niloticus). In XX fish, mutation of cyp17a1 gene led to a female-to-male sex reversal with a significant decline in 17β-estradiol (E2) and testosterone (T) production, and ectopic expression of male-biased markers (Dmrt1 and Gsdf) in gonads from the critical window of sex determination. Sex reversal was successfully rescued via T or E2 administration, and ovarian characteristics were maintained after termination of E2 supplementation in the absence of endogenous estrogen production in cyp17a1  -/--XX fish. Likewise, deficiencies in T and 11-KT production in both cyp17a1  -/--XX sex reversed males and cyp17a1  -/--XY mutants resulted in meiotic initiation delays, vas deferens obstruction and sterility due to excessive apoptosis and abnormal mitochondrial morphology. However, 11-KT treatment successfully rescued the dysspermia to produce normal sperm in cyp17a1  -/- male fish. Significant increases in fshβ, lhβ, and gth receptors in cyp17a1  -/- mutants may excessively upregulate steroidogenic gene expression in Leydig cells through a feedback loop. Taken together, our findings demonstrate that Cyp17a1 is indispensable for E2 production, which is fundamental for female sex determination and differentiation in XX tilapia. Additionally, Cyp17a1 is essential for T and 11-KT production, which further promotes spermatogenesis and fertility in XY males.

scholarly journals Metabolism and Sex Differentiation in Animals from a Starvation Perspective

2021 ◽  
pp. 1-11
Author(s):  
Yuta Sakae ◽  
Minoru Tanaka
Keyword(s):  
Sex Determination ◽  
Environmental Changes ◽  
Sex Differentiation ◽  
Green Light ◽  
Acid Synthesis ◽  
Sex Reversal ◽  
Environmental Sex Determination ◽  
Biological Factors ◽  
Signal Transducers ◽  
Male Sex

Animals determine their sex genetically (GSD: genetic sex determination) and/or environmentally (ESD: environmental sex determination). Medaka (<i>Oryzias latipes</i>) employ a XX/XY GSD system, however, they display female-to-male sex reversal in response to various environmental changes such as temperature, hypoxia, and green light. Interestingly, we found that 5 days of starvation during sex differentiation caused female-to-male sex reversal. In this situation, the metabolism of pantothenate and fatty acid synthesis plays an important role in sex reversal. Metabolism is associated with other biological factors such as germ cells, HPG axis, lipids, and epigenetics, and supplys substances and acts as signal transducers. In this review, we discuss the importance of metabolism during sex differentiation and how metabolism contributes to sex differentiation.

scholarly journals Sex reversal and ontogeny under climate change and chemical pollution: are there interactions between the effects of elevated temperature and a xenoestrogen on early development in agile frogs?

2020 ◽  
Author(s):  
Zsanett Mikó ◽  
Edina Nemesházi ◽  
Nikolett Ujhegyi ◽  
Viktória Verebélyi ◽  
János Ujszegi ◽  
...  
Keyword(s):  
Climate Change ◽  
High Temperature ◽  
Sex Determination ◽  
Body Mass ◽  
Endocrine Disrupting Chemicals ◽  
Sex Reversal ◽  
Chemical Pollution ◽  
Genetic Sexing ◽  
Simultaneous Exposure ◽  
Individual Fitness

Anthropogenic environmental change poses a special threat to species in which genetic sex determination can be overwritten by the thermal and chemical environment. Endocrine disrupting chemicals as well as extreme temperatures can induce sex reversal in such species, with wide-ranging consequences for fitness, demography, population viability and evolution. Despite accumulating evidence suggesting that chemical and thermal effects may interact in ecological contexts, little is known about their combined effects on sex reversal. Here we assessed the simultaneous effects of high temperature (masculinizing agent) and 17α-ethinylestradiol (EE2), a widespread xenoestrogen (feminizing agent), on sexual development and fitness-related traits in agile frogs (Rana dalmatina). We exposed tadpoles to a six-days heat wave (30°C) and/or an ecologically relevant concentration of EE2 (30 ng/L) in one of three consecutive larval periods, and diagnosed sex reversals two months after metamorphosis using species-specific markers for genetic sexing. We found that high temperature induced female-to-male sex reversal, decreased survival, delayed metamorphosis, decreased body mass at metamorphosis, and increased the proportion of animals that had no fat bodies, while EE2 had no effect on these traits. Simultaneous exposure to heat and EE2 had non-additive effects on juvenile body mass, which were dependent on treatment timing and further complicated by a negative effect of sex reversal on body mass. These results show that environmentally relevant exposure to EE2 does not diminish the masculinizing effects of high temperature. Instead, our findings on growth suggest that climate change and chemical pollution may have complex consequences for individual fitness and population persistence in species with environment-sensitive sex determination.

scholarly journals Transcriptional Regulation of the Y-Linked Mammalian Testis-Determining Gene SRY

2021 ◽  
pp. 1-9
Author(s):  
Naoki Okashita ◽  
Makoto Tachibana
Keyword(s):  
Sex Determination ◽  
Sex Differentiation ◽  
Disorders Of Sex Development ◽  
Sex Reversal ◽  
Cis Acting ◽  
Male Development ◽  
Sex Development ◽  
Epigenetic Modifier ◽  
Male Sex ◽  
Testis Determining Gene

Mammalian male sex differentiation is triggered during embryogenesis by the activation of the Y-linked testis-determining gene <i>SRY</i>. Since insufficient or delayed expression of <i>SRY</i> results in XY gonadal sex reversal, accurate regulation of <i>SRY</i> is critical for male development in XY animals. In humans, dysregulation of <i>SRY</i> may cause disorders of sex development. Mouse <i>Sry</i> is the most intensively studied mammalian model of sex determination. <i>Sry</i> expression is controlled in a spatially and temporally stringent manner. Several transcription factors play a key role in sex determination as trans-acting factors for <i>Sry</i> expression. In addition, recent studies have shown that several epigenetic modifications of <i>Sry</i> are involved in sex determination as cis-acting factors for <i>Sry</i> expression. Herein, we review the current understanding of transcription factor- and epigenetic modifier-mediated regulation of <i>SRY</i>/<i>Sry</i> expression.

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