Temperature dependent sex determination

Projection models are being increasingly used to manage threatened taxa by estimating their responses to climate change. Sea turtles are particularly susceptible to climate change as they have temperature-dependent sex determination and increased sand temperatures on nesting beaches could result in the 'feminisation' of hatchling sex ratios for some populations. This study modelled likely long-term trends in sand temperatures and hatchling sex ratios at an equatorial nesting site for endangered green turtles (Chelonia mydas) and critically endangered hawksbill turtles (Eretmochelys imbricata)...

Renziehausen, JM, Bergquist, AM, Park, J-H, Hill, EC, Wells, AJ, Stout, JR, and Fukuda, DH. Time of day effects on anaerobic performance using a nonmotorized treadmill. J Strength Cond Res 37(10): 2002-2007, 2023-The purpose of this study was to determine the effects of time of day on performance during a maximal effort sprinting assessment (30nmt) and determine potential differences based on chronotype and sex. Twenty-six recreationally active men (n = 12) and women (n = 14) between the ages of 18 and 35 years old (21...

The threatened Mojave desert tortoise (Gopherus agassizii) exhibits temperature-dependent sex determination, and individuals appear externally sexually monomorphic until sexual maturity. A non-surgical sex identification method that is suitable for a single in situ encounter with hatchlings is essential for minimizing handling of wild animals. We tested (1) whether plasma testosterone quantified by enzyme-linked immunosorbent assay differentiated males from females in 0-3 month old captive hatchlings, and (2) whether an injection of follicle-stimulating hormone (FSH) differentially elevates testosterone in male hatchlings to aid in identifying sex...

The mode of sex determination in vertebrates can be categorized as genotypic or environmental. In the case of genotypic sex determination (GSD), the sexual fate of an organism is determined by the chromosome composition with some having dominant genes, named sex-determining genes, that drive the sex phenotypes. By contrast, many reptiles exhibit environmental sex determination (ESD), whereby environmental stimuli drive sex determination, and most notably temperature. To date, temperature-dependent sex determination (TSD) has been found in most turtles, some lizards, and all crocodylians, but commonalities in the controlling processes are not well established...

Although physiological responses to the thermal environment are most frequently investigated using constant temperatures, the incorporation of thermal variability can allow for a more accurate prediction of how thermally sensitive species respond to a rapidly changing climate. In species with temperature-dependent sex determination (TSD), developmental responses to incubation temperature are mediated by several genes involved in gonadal differentiation. Kdm6b and Dmrt1 respond to cool incubation temperatures and are associated with testis development, while Foxl2 and Cyp19A1 respond to warm incubation temperatures and are associated with ovary development...

The application and prognostic nature of systemic inflammatory reaction syndrome (SIRS) is still being researched, as using SIRS parameters to predict patient status is cheap, efficient, fast, and easy. The study aimed to determine SIRS markers and postoperative complications occurrence in patients undergoing kidney tumor surgery, and to verify if SIRS occurrence depends on age, sex, BMI (body mass index), comorbidities, patients' general condition before the surgery, type of surgery, intraoperative blood loss, or intraoperative ischemia time...

Temperature sex determination (TSD) in reptiles has been studied in order to elucidate the mechanisms by which temperature is transformed into a biological signal that determines the sex of the embryo. Temperature is thought to trigger signals that alter gene expression and hormone metabolism, that will determine the development of female or male gonads. In this review we focus on collecting and discussing important and recent information on the role of maternal steroid hormones in sex determination in oviparous reptiles such as crocodiles, turtles and lizards that possess TSD...

AbstractSex chromosomes rapidly turn over in several taxonomic groups. Sex chromosome turnover is generally thought to start with the appearance of a new sex-determining gene on an autosome while an old sex-determining gene still exists, followed by the fixation of the new one. However, we do not know how prevalent the transient state is, where multiple sex-determining loci coexist within natural populations. Here, we removed a Y chromosome with a master male-determining gene DMY from medaka fish using high temperature-induced sex-reversed males...

Sexual selection often shapes social behavioural activities, such as movement in the environment to find possible partners, performance of displays to signal dominance and courtship behaviours. Such activities may be negatively influenced by increasing temperatures, especially in ectotherms, because individuals either have to withstand the unfavourable condition or are forced to allocate more time to thermoregulation by increasing shelter seeking behaviour. Thus, they "miss" opportunities for social and reproductive interactions...

The Anti-mullerian hormone (AMH), also known as Mullerian inhibiting substance (MIS), is a glycoprotein that belongs to transforming growth factor β superfamily. The significance of AMH during gonadal differentiation is not clearly deciphered in reptiles. Hence, current study aims to know the onset of AMH secretion and its functional role in Mullerian duct regression gonadal differentiation in tropical lizard, Calotes versicolor which exhibits a. novel Female-Male-Female-Male (FMFM) pattern of temperature-dependent sex determination (TSD)...

The multi-ocellated racerunner, Eremias multiocellata , was considered to have temperature-dependent sex determination (TSD), as its sex ratio can be influenced at different temperatures. However, such an observation contrasts with recent findings that suggest TSD is less common than previously thought. Here, a genotyping-by-sequencing (GBS) approach was employed to identify sex-linked markers in the E. multiocellata , for which the mechanism choice of TSD or GSD is still controversial. We preliminarily identified 119 sex-linked markers based on sex-associated sex-specific sequences, 97% of which indicated female heterogamety...

Childhood adversity can induce maladaptive behaviors and increase risk for affective disorders, post-traumatic stress disorder, personality disorders, and vulnerability to stress in adulthood. Deprivation of maternal care interrupts brain development through the disturbance of various neurotransmitters, however, the details remain unclear. The features of the symptoms of disorders are largely determined by early stress protocol, genetic characteristics (line), and the sex of the animals. The purpose of current study was (1) to assess behavioral changes in adult Wistar rats of both sexes after early life stress; (2) to determine the levels of monoamines in brain structures involved in the motor, emotional, and social reactions in rats aged 1 and 2 months; and (3) to determine the level of monoamines after physical or emotional stress in adult rats...

In many reptile species, gonadal sex is affected by environmental temperature during a critical period of embryonic development-a process known as temperature-dependent sex determination (TSD).1 The oviparous red-eared slider turtle, Trachemys scripta, has a warm-female/cool-male TSD system and is among the best-studied members of this group.2 When incubated at low temperatures, the somatic cells of the bipotential gonad differentiate into Sertoli cells, the support cells of the testis, whereas at high temperatures, they differentiate into granulosa cells, the support cells of the ovary...

Wildlife exhibits various sex-determination systems where sex chromosomes and environmental temperatures may both contribute to individual sexual development. The causes and consequences of this variability are important questions for evolutionary ecology, especially in light of ongoing environmental change. Amphibians and reptiles are emerging as a key group for studying these questions, with new data accumulating acceleratingly. We collected empirical data from earlier databases, reviews and primary literature to create the most up-to-date database on herpetological sex determination...

Vertebrate sex is typically determined genetically, but in many ectotherms sex can be determined by genes (Genetic Sex Determination: GSD), temperature (Temperature-dependent Sex Determination: TSD), or interactions between genes and temperature during development. Temperature dependent sex determination may involve GSD systems with either male or female heterogamety (XX/XY or ZZ/ZW) where temperature overrides chromosomal sex determination to cause a mismatch between genetic sex and phenotypic sex (sex-reversal)...

Each parent can influence offspring phenotypes via provisioning of the zygote or sex-specific DNA methylation. Transgenerational plasticity may therefore depend on environmental conditions experienced by each parent. We tested this hypothesis by conducting a fully factorial experiment across three generations of guppies (Poecilia reticulata), determining the effects of warm (28oC) and cold (21oC) thermal backgrounds of mothers and fathers on mass and length, and thermal performance (sustained [Ucrit] and sprint swimming speeds, citrate synthase and lactate dehydrogenase activities; 18, 24, 28, 32 and 36oC test temperatures) of sons and daughters...

Over the past two decades, there has been an astounding growth in the documentation of vertebrate facultative parthenogenesis (FP). This unusual reproductive mode has been documented in birds, non-avian reptiles-specifically lizards and snakes-and elasmobranch fishes. Part of this growth among vertebrate taxa is attributable to awareness of the phenomenon itself and advances in molecular genetics/genomics and bioinformatics, and as such our understanding has developed considerably. Nonetheless, questions remain as to its occurrence outside of these vertebrate lineages, most notably in Chelonia (turtles) and Crocodylia (crocodiles, alligators and gharials)...

The adult sex ratio (ASR, the proportion of males in the adult population) is an emerging predictor of reproductive behaviour, and recent studies in birds and humans suggest it is a major driver of social mating systems and parental care. ASR may also influence genetic mating systems. For instance male-skewed ASRs are expected to increase the frequency of multiple paternity (defined here as a clutch or litter sired by two or more males) due to higher rates of coercive copulations by males, and/or due to females exploiting the opportunity of copulation with multiple males to increase genetic diversity of their offspring...

Sex determination (SD) is a crucial developmental process, but its molecular underpinnings are very diverse, both between and within species. SD mechanisms have traditionally been categorized as either genetic (GSD) or environmental (ESD), depending on the type of cue that triggers sexual differentiation. However, mixed systems, with both genetic and environmental components, are more prevalent than previously thought. Here, we show theoretically that environmental effects on expression levels of genes within SD regulatory mechanisms can easily trigger within-species evolutionary divergence of SD mechanisms...

Developmental conditions can profoundly impact key life history traits of the individual. In cases where offspring sex is driven by developmental reaction norms, permanent changes to the phenotype can fundamentally alter life history trajectories. Sex determination mechanisms in reptiles are remarkably diverse, including well-characterised genetic and temperature-dependent sex determination. In rarer, but increasingly more commonly documented cases, sex can also be determined by a combination of the two, with temperature overriding the genetically determined sex...