Deficiency of the paternally-expressed imprinted Peg3 gene in mice has sexually dimorphic consequences for offspring communication and social behaviour.

Introduction: Imprinted genes are expressed from one parental allele as a consequence of epigenetic processes initiated in the germline. Consequently, their ability to influence phenotype depends on their parent-of-origin. Recent research suggests that the sex of the individual expressing the imprinted gene is also important. We have previously reported that genetically wildtype (WT) dams carrying and caring for pups mutant for PEG3 exhibit anxiety-like behaviours and their mutant pups show a reduction in ultrasonic vocalisation when separated from their mothers. Sex-specificity was not examined. Methods: WT female mice were mated with WT, heterozygous Peg3-/+ or homozygous Peg3-/- studs to generate all WT (control), 50:50 mixed or 100% mutant litters, respectively, followed by behavioural assessment of both dams and their pups. Results: We reproduced our original finding that WT dams carrying and caring for 100% mutant litters exhibit postpartum anxiety-like symptoms and delayed pup retrieval. Additionally, these WT dams were found to allocate less time to pup-directed care behaviours relative to controls. Male Peg3-deficient pups demonstrated significantly reduced vocalisation with a more subtle communication deficit in females. Postweaning, male mutants exhibited deficits across a number of key social behaviours as did WT males sharing their environment with mutants. Only modest variations in social behaviour were detected in experimental females. Discussion: We have experimentally demonstrated that Peg3 deficiency confined to the offspring causes anxiety in mouse mothers and atypical behaviour including deficits in communication in their male offspring. A male-specific reduction in expression PEG3 in the fetally-derived placenta has previously been associated with maternal depression in human pregnancy. Maternal mood disorders such as depression and anxiety are associated with delays in language development and neuroatypical behaviour more common in sons. Peg3 deficiency could drive the association of maternal and offspring behavioural disorders reported in humans.

Digital measurement of deciduous tooth dimensions in China: A cross-sectional survey.

OBJECTIVE: Crown dimensions data of deciduous teeth hold anthropological, forensic, and archaeological value. However, such information remains scarce for the Chinese population. This multi-center study aimed to collect a large sample of deciduous crown data from Chinese children using three-dimensional measurement methods and to analyze their dimensions. DESIGN: A total of 1592 children's deciduous dentition samples were included, and the sample size was distributed according to Northeast, North, East, Northwest, Southwest and South China. Digital dental models were reconstructed from plaster dental models. Independent sample t test, paired t test, principal component analysis (PCA), and factor analysis (FA) were used to analyze the tooth crown dimensions. RESULT: 18,318 deciduous teeth from 1592 children were included. Males exhibited slightly larger values than females. The range of sexual dimorphism percentages for each measurement was as follows: mesiodistal diameter (0.40-2.08), buccolingual diameter (0.13-2.24), and maxillogingival diameter (0.48-3.37). The FA results showed that the main trend of crown dimensions changes was the simultaneous increase or decrease in mesiodistal diameter, buccolingual diameter and maxillogingival diameter in three directions. CONCLUSION: This is the first large-scale survey of deciduous tooth crown dimensions in China, which supplements the data of deciduous tooth measurement and provides a reference for clinical application.

Maternal nano-titanium dioxide inhalation exposure alters placental cyclooxygenase and oxidant balance in a sexually dimorphic manner.

The placenta plays a critical role in nutrient-waste exchange between the maternal and fetal circulation, and thus impacts fetal growth and development. We have previously shown that nano-titanium dioxide (nano-TiO2) inhalation exposure during gestation decreased fetal female pup and placenta mass [1], which persists in the following generation [2]. In utero exposed females, once mated, their offspring's placentas had increased capacity for H2O2 production. Generation of oxidants such as hydrogen peroxide (H2O2), have been shown to impact cyclooxygenase activity, specifically metabolites such as prostacyclin (PGI2) or thromboxane (TXA2). Therefore, we hypothesized that maternal nano-TiO2 inhalation exposure during gestation results in alterations in placental production of prostacyclin and thromboxane mediated by enhanced H2O2 production in a sexually dimorphic manner. Pregnant Sprague-Dawley rats were exposed to nano-TiO2 aerosols or filtered air (sham--control) from gestational day (GD) 10-19. Dams were euthanized on GD 20, and fetal serum and placental tissue were collected based on fetal sex. Fetal placental zones (junctional zone (JZ) and labyrinth zone (LZ)) were assessed for xanthine oxidoreductase (XOR) activity, H2O2, and catalase activity, as well as 6-keto-PGF1α and TXB2 levels. Nano-TiO2 exposed fetal female LZ demonstrated significantly greater XOR activity compared to exposed males. Exposed fetal female LZ also demonstrated significantly diminished catalase activity compared to sham-control females. Exposed fetal female LZ had significantly increased abundance of 6-keto-PGF1α compared to sham-control females and increased TXB2 compared to exposed males. In the aggregate these data indicate that maternal nano-TiO2 inhalation exposure has a greater impact on redox homeostasis and PGI2/TXA2 balance in the fetal female LZ. Future studies need to address if treatment with an XO inhibitor during gestation can prevent diminished fetal female growth during maternal nano-TiO2 inhalation exposure.

Evolutionary divergence of plasticity in brain morphology between ecologically divergent habitats of Trinidadian guppies.

Phenotypic plasticity is critical for organismal performance and can evolve in response to natural selection. Brain morphology is often developmentally plastic, affecting animal performance in a variety of contexts. However, the degree to which plasticity of brain morphology evolves has rarely been explored. Here we use Trinidadian guppies (Poecilia reticulata), which are known for their repeated adaptation to high-predation (HP) and low-predation (LP) environments, to examine the evolution and plasticity of brain morphology. We exposed second-generation offspring of individuals from HP and LP sites to two different treatments: predation cues and conspecific social environment. Results show that LP guppies had greater plasticity in brain morphology compared to their ancestral HP population, suggesting that plasticity can evolve in response to environmentally divergent habitats. We also show sexual dimorphism in the plasticity of brain morphology, highlighting the importance of considering sex-specific variation in adaptive diversification. Overall, these results may suggest the evolution of brain morphology plasticity as an important mechanism that allows for ecological diversification and adaptation to divergent habitats.

Mitochondrial remodeling underlying age-induced skeletal muscle wasting: let's talk about sex.

Sarcopenia is associated with reduced quality of life and premature mortality. The sex disparities in the processes underlying sarcopenia pathogenesis, which include mitochondrial dysfunction, are ill-understood and can be decisive for the optimization of sarcopenia-related interventions. To improve the knowledge regarding the sex differences in skeletal muscle aging, the gastrocnemius muscle of young and old female and male rats was analyzed with a focus on mitochondrial remodeling through the proteome profiling of mitochondria-enriched fractions. To the best of our knowledge, this is the first study analyzing sex differences in skeletal muscle mitochondrial proteome remodeling. Data demonstrated that age induced skeletal muscle atrophy and fibrosis in both sexes. In females, however, this adverse skeletal muscle remodeling was more accentuated than in males and might be attributed to an age-related reduction of 17beta-estradiol signaling through its estrogen receptor alpha located in mitochondria. The females-specific mitochondrial remodeling encompassed increased abundance of proteins involved in fatty acid oxidation, decreased abundance of the complexes subunits, and enhanced proneness to oxidative posttranslational modifications. This conceivable accretion of damaged mitochondria in old females might be ascribed to low levels of Parkin, a key mediator of mitophagy. Despite skeletal muscle atrophy and fibrosis, males maintained their testosterone levels throughout aging, as well as their androgen receptor content, and the age-induced mitochondrial remodeling was limited to increased abundance of pyruvate dehydrogenase E1 component subunit beta and electron transfer flavoprotein subunit beta. Herein, for the first time, it was demonstrated that age affects more severely the skeletal muscle mitochondrial proteome of females, reinforcing the necessity of sex-personalized approaches towards sarcopenia management, and the inevitability of the assessment of mitochondrion-related therapeutics.

MGMT Methylation and Differential Survival Impact by Sex in Glioblastoma.

Introduction: Sex differences in glioblastoma (GBM) have been observed in incidence, genetic and epigenetic alterations, and immune response. These differences have extended to the methylation of the MGMT promoter, which critically impacts temozolomide resistance. However, the association between sex, MGMT methylation, and survival is poorly understood, which this study sought to evaluate. Methods: A retrospective cohort study was conducted and reported following STROBE guidelines, based on adults with newly diagnosed GBM who received their first surgical intervention at Cleveland Clinic (Ohio, USA) between 2012 and 2018. Kaplan-Meier and multivariable Cox proportional hazards models were used to analyze the association between sex and MGMT promoter methylation status on overall survival (OS). MGMT was defined as methylated if the mean of CpG 1-5 ≥ 12. Propensity score matching was performed on a subset of patients to evaluate the effect of individual CpG site methylation. Results: A total of 464 patients had documented MGMT methylation status with a mean age of 63.4 (range 19-93) years. A total of 170 (36.6%) were female, and 133 (28.7%) received gross total resection as a first intervention. A total of 42.5% were MGMT methylated, with females more often having MGMT methylation than males (52.1% vs. 37.4%, p = 0.004). In univariable analysis, OS was significantly longer for MGMT promoter methylated than un-methylated groups for females (2 yr: 36.8% vs. 11.1%; median: 18.7 vs. 9.5 months; p = 0.001) but not for males (2 yr: 24.3% vs. 12.2%; median: 12.4 vs. 11.3 months; p = 0.22, p for MGMT-sex interaction = 0.02). In multivariable analysis, MGMT un-methylated versus methylated promoter females (2.07; 95% CI, 1.45-2.95; p < 0.0001) and males (1.51; 95% CI, 1.14-2.00; p = 0.004) had worse OS. Within the MGMT promoter methylated group, males had significantly worse OS than females (1.42; 95% CI: 1.01-1.99; p = 0.04). Amongst patients with data on MGMT CpG promoter site methylation values (n = 304), the median (IQR) of CpG mean methylation was 3.0% (2.0, 30.5). Females had greater mean CpG methylation than males (11.0 vs. 3.0, p < 0.002) and higher per-site CpG methylation with a significant difference at CPG 1, 2, and 4 (p < 0.008). After propensity score matching, females maintained a significant survival benefit (18.7 vs. 10.0 months, p = 0.004) compared to males (13.0 vs. 13.6 months, p = 0.76), and the pattern of difference was significant (P for CpG-sex interaction = 0.03). Conclusions: In this study, females had higher mean and individual CpG site methylation and received a greater PFS and OS benefit by MGMT methylation that was not seen in males despite equal degrees of CpG methylation.

Validation and recalibration of sex estimation methods using pubic nonmetric traits for the Chilean population.

Chile had a violent military coup (1973-1990) that resulted in 3,000 victims declared detained, missing or killed; many are still missing and unidentified. Currently, the Human Rights Unit of the Forensic Medical Service in Chile applies globally recognised forensic anthropological approaches, but many of these methods have not been validated in a Chilean sample. As current research has demonstrated population-specificity with extant methods, the present study aims to validate sex estimation methods in a Chilean population and thereafter establish population-specific equations. A sample of 265 os coxae of known age and sex of adult Chileans from the Santiago Subactual Osteology Collection were analysed. Visual assessment and scoring of the pelvic traits were performed in accordance with the Phenice (1969) and Klales et al. (2012) methods. The accuracy of Phenice (1969) in the Chilean sample was 96.98%, with a sex bias of 7.68%. Klales et al. (2012) achieved 87.17% accuracy with a sex bias of -15.39%. Although both methods showed acceptable classification accuracy, the associated sex bias values are unacceptable in forensic practice. Therefore, six univariate and eight multivariate predictive models were formulated for the Chilean population. The most accurate univariate model was the ventral arc at 96.6%, with a sex bias of 5.2%. Classification accuracy using all traits was 97.0%, with a sex bias of 7.7%. This study provides Chilean practitioners a population-specific morphoscopic standard with associated classification probabilities acceptable to accomplish legal admissibility requirements in human rights and criminal cases specific to the second half of the 20th century.

Screening of temperature-responsive signalling molecules during sex differentiation in Asian yellow pond turtle (Mauremys mutica).

BACKGROUND: The Asian yellow pond turtle (Mauremys mutica) is an important commercial freshwater aquaculture species in China. This species is a highly sexually dimorphic species, with males growing at a faster rate than females and exhibits temperature-dependent sex determination (TSD), in which the incubation temperature during embryonic development determines the sexual fate. However, the mechanisms of the sex determination or sex differentiation in the Asian yellow pond turtle are remain a mystery. RESULTS: Temperature-specific gonadal transcriptomics of the Asian yellow pond turtle were performed during the thermosensitive period (stage 15) using RNA-seq technology to identify candidate genes that initiate gonadal differentiation. We uncovered candidates that were the first to respond to temperature. These candidates were sexually dimorphic in expression, reflecting differences in gonadal (Cirbp, Runx1) and germline differentiation (Vasa, Nanos1, Piwil2), gametogenesis (Hmgb3, Zar1, Ovoinhibitor-like, Kif4), steroid hormone biosynthesis (Hsd17b5, Hsd17b6), heat shock (Dnajb6, Hsp90b1, Hsp90aa1) and transient receptor potential channel genes (Trpm1, Trpm4, Trpm6, Trpv1). CONCLUSIONS: Our work will provide important genetic information to elucidate the mechanisms of sex control in the Asian yellow pond turtles, and will contribute important genetic resources for further studies of temperature-dependent sex determination in turtles.

Rethinking pathways to the dioecy-polyploidy association: Genera with many dioecious species have fewer polyploids.

PREMISE: Numerous studies have found a positive association between dioecy and polyploidy; however, this association presents a theoretical conflict: While polyploids are predicted to benefit from self-reproduction for successful establishment, dioecious species cannot self-reproduce. We propose a theoretical framework to resolve this apparent conflict. We hypothesize that the inability of dioecious species to self-reproduce hinders their establishment as polyploids. We therefore expect that genera with many dioecious species have fewer polyploids, leading to a negative association between polyploidy and dioecy across genera. METHODS: We used three publicly available databases to determine ploidy and sexual systems for 131 genera and 546 species. We quantified (1) the relationship between the frequency of polyploid species and the frequency of dioecious species across genera, and (2) the proportion of polyploids with hermaphroditism and dioecy across species, adjusting for phylogenetic history. RESULTS: Across genera, we found a negative relationship between the proportion of polyploids and the proportion of dioecious species, a consistent trend across clades. Across all species, we found that sexual system (dioecious or not) was not associated with polyploidy. CONCLUSIONS: Polyploids are rare in genera in which the majority of species are dioecious, consistent with the theory that self-reproduction favors polyploid establishment. The low frequency of polyploidy among dioecious species indicates the association is not as widespread as previously suggested. Our findings are consistent with previous studies identifying a positive relationship between the two traits, but only if polyploidy promotes a transition to dioecy, and not the reverse.

Female-selective mechanisms promoting migraine.

Sexual dimorphism has been revealed for many neurological disorders including chronic pain. Prelicinal studies and post-mortem analyses from male and female human donors reveal sexual dimorphism of nociceptors at transcript, protein and functional levels suggesting different mechanisms that may promote pain in men and women. Migraine is a common female-prevalent neurological disorder that is characterized by painful and debilitating headache. Prolactin is a neurohormone that circulates at higher levels in females and that has been implicated clinically in migraine. Prolactin sensitizes sensory neurons from female mice, non-human primates and humans revealing a female-selective pain mechanism that is conserved evolutionarily and likely translationally relevant. Prolactin produces female-selective migraine-like pain behaviors in rodents and enhances the release of calcitonin gene-related peptide (CGRP), a neurotransmitter that is causal in promoting migraine in many patients. CGRP, like prolactin, produces female-selective migraine-like pain behaviors. Consistent with these observations, publicly available clinical data indicate that small molecule CGRP-receptor antagonists are preferentially effective in treatment of acute migraine therapy in women. Collectively, these observations support the conclusion of qualitative sex differences promoting migraine pain providing the opportunity to tailor therapies based on patient sex for improved outcomes. Additionally, patient sex should be considered in design of clinical trials for migraine as well as for pain and reassessment of past trials may be warranted.

Macrophage: A key player in neuropathic pain.

Research on the relationship between macrophages and neuropathic pain has flourished in the past two decades. It has long been believed that macrophages are strong immune effector cells that play well-established roles in tissue homeostasis and lesions, such as promoting the initiation and progression of tissue injury and improving wound healing and tissue remodeling in a variety of pathogenesis-related diseases. They are also heterogeneous and versatile cells that can switch phenotypically/functionally in response to the micro-environment signals. Apart from microglia (resident macrophages of both the spinal cord and brain), which are required for the neuropathic pain processing of the CNS, neuropathic pain signals in PNS are influenced by the interaction of tissue-resident macrophages and BM infiltrating macrophages with primary afferent neurons. And the current review looks at new evidence that suggests sexual dimorphism in neuropathic pain are caused by variations in the immune system, notably macrophages, rather than the neurological system.

Neuropathic pain is defined by the International Association for the Study of Pain as pain triggered or caused by primary damage to or dysfunction of the nervous system. Following intensive research into the mechanisms of neuropathic pain, macrophages have been revealed to play an important role in pathologic pain following nerve injury. Macrophages dynamically monitor the microenvironment to maintain tissue homeostasis. Once a macrophage is exposed to a pathologic stimulus, it in turn alters its functional phenotype and interacts with nociceptors, leading to neuropathic pain. This review wants to delve into the biology of macrophages in the central and peripheral nervous system, how they are related to play a role in neuropathic pain and whether there is sexual dimorphism in macrophages.

Are there sex differences in the variability of fasting metabolism?

There is evidence across species and across many traits that males display greater between-individual variance. In contrast, (premenopausal) females display large within-individual variance in sex hormone concentrations, which can increase within-individual variance in many other parameters. The latter may contribute to the lower representation of females in metabolic research. This study is a pooled secondary analysis of data from 7 crossover studies to investigate the between-individual and the within-individual variance in fasting plasma metabolites, resting metabolic rate (RMR) and body mass. Females demonstrated higher within-individual variability of plasma 17ß-estradiol (CV 15±15 % for males vs 38±34 % for females, p<0.001) and progesterone concentrations (CV 13±11 % for males vs 52±51 % for females, p<0.001) but there were no meaningful differences in the variability of plasma glucose (CV 4±3 % for males vs 5 ± 5 % for females), insulin, lactate, triglycerides (CV 15±9 % for males vs 15 ± 10 % for females), and non-esterified fatty acid concentrations, nor in RMR and body mass (CV 0.43±0.34 % for males vs for 0.42±0.33 % females; p>0.05 for all outcomes). Males displayed higher between-individual variance in RMR compared to females (SD 224 kcal×day-1 for males vs 151 kcal×day-1 for females). In conclusion, these data do not provide evidence that females show greater within-individual variability in many fasting metabolic variables, RMR or body mass compared to males. We conclude that including females in metabolic research is unlikely to introduce greater within-individual variance when using the recruitment and control procedures described in these studies.

Sex-based differences in growth-related IGF1 signaling in response to PAPP-A2 deficiency: comparative effects of rhGH, rhIGF1 and rhPAPP-A2 treatments.

BACKGROUND: Children with pregnancy-associated plasma protein-A2 (PAPP-A2) mutations resulting in low levels of bioactive insulin-like growth factor-1 (IGF1) and progressive postnatal growth retardation have improved growth velocity and height following recombinant human (rh)IGF1 treatment. The present study aimed to evaluate whether Pappa2 deficiency and pharmacological manipulation of GH/IGF1 system are associated with sex-specific differences in growth-related signaling pathways. METHODS: Plasma, hypothalamus, pituitary gland and liver of Pappa2ko/ko mice of both sexes, showing reduced skeletal growth, and liver of these mice treated with rhGH, rhIGF1 and rhPAPP-A2 from postnatal day (PND) 5 to PND35 were analyzed. RESULTS: Reduced body and femur length of Pappa2ko/ko mice was associated with increases in: (1) components of IGF1 ternary complexes (IGF1, IGFBP5/Igfbp5, Igfbp3, Igfals) in plasma, hypothalamus and/or liver; and (2) key signaling regulators (phosphorylated PI3K, AKT, mTOR, GSK3ß, ERK1/2 and AMPKα) in hypothalamus, pituitary gland and/or liver, with Pappa2ko/ko females having a more prominent effect. Compared to rhGH and rhIGF1, rhPAPP-A2 specifically induced: (1) increased body and femur length, and reduced plasma total IGF1 and IGFBP5 concentrations in Pappa2ko/ko females; and (2) increased Igf1 and Igf1r levels and decreased Ghr, Igfbp3 and Igfals levels in the liver of Pappa2ko/ko females. These changes were accompanied by lower phospho-STAT5, phospho-AKT and phospho-ERK2 levels and higher phospho-AMPK levels in the liver of Pappa2ko/ko females. CONCLUSIONS: Sex-specific differences in IGF1 system and signaling pathways are associated with Pappa2 deficiency, pointing to rhPAPP-A2 as a promising drug to alleviate postnatal growth retardation underlying low IGF1 bioavailability in a female-specific manner.

Understanding the physiological role of pregnancy-associated plasma protein-A2 (PAPP-A2), a proteinase involved in the insulin-like growth factor-1 (IGF1) availability to regulate growth, could provide insight into new treatments for patients with short stature and skeletal abnormalities. Although progressive postnatal growth retardation in patients with PAPP-A2 mutations can differ between males and females, we do not know the underlying differences in IGF1 system and signaling, and their response to treatment that contribute to growth improvement. The present study examines whether Pappa2 deficiency and pharmacological administration of rhGH, rhIGF1 and rhPAPP-A2 are associated with sex-specific differences in IGF1 ternary complexes and IGF1 signaling pathways. Reduced body and femur length of Pappa2-deficient mice was associated with sex- and tissue-specific alteration of IGF ternary/binary complexes and IGF1 signaling pathways. rhPAPP-A2 treatment induced female-specific increase in body and femur length and reduction in IGF ternary/binary complexes through STAT5-AKT-ERK2-AMPK signaling pathways in liver. The involvement of PAPP-A2 in sex-based growth physiology supports the use of promising drugs to alleviate postnatal growth retardation underlying low IGF1 bioavailability in a female-specific manner.

Retrospective evaluation of the morphometric properties of intact maxillary sinus using cone-beam computed tomography for sex estimation in an Indian population.

Background: Sex estimation is crucial to forensic examinations. In order to estimate sex, intact bones are used if the majority of bones are severely deformed and recovered in fragments. This study aims to analyze sexual dimorphism in intact maxillary sinuses using CBCT scanning to evaluate morphometric properties for sex identification. Methods: A total of 318 subjects, consisting of 159 males and 159 females, aged between 20 and 60 years without sinus pathology were included in this diagnostic, retrospective cross-sectional study. Bilateral measurements of the volume, height, width, and length of the maxillary sinuses were obtained and compared to evaluate the differences between sexes. Subsequently, a descriptive analysis using mean and standard deviation was performed, followed by a comparison between sexes with a p-value being less than 0.05 and Student's t-test. Finally, a discriminant analysis was performed separately for the right and left maxillary sinuses. Results: Males and females showed statistically significant variations in the length, width, and volume of the maxillary sinuses. Specifically, on the right side, males had longer maxillary sinuses than females (t = 5.6203, p < 0.0001). Meanwhile, on the left side, females had wider maxillary sinuses than males (t = 8.621, plt0.0001). In addition, males had greater volumes of maxillary sinuses on the right (t = 6.373, p < 0.0001) and left (t = 3.091, p < 0.0001) sides than females. The results of the discriminant analysis showed that the left width parameter had the highest accuracy of sex estimation (74.21%), followed by the Right Length (70.07%) and left volume (66.66%) parameters. The left height parameter had the lowest accuracy of sex estimation (49.37%). Conclusion: In forensic odontology, the volume of maxillary sinus can serve as a valid radiographic indicator of sex estimation.

Weight as an indicator of enclosure suitability in Livingstone's fruit bats (Pteropus livingstonii).

Obesity is common in zoo animals, and both dietary management and the provision of adequate opportunities for exercise are needed to tackle it. We used 30 years of records from Jersey Zoo to compare the weight and forearm length of wild and captive-born Livingstone's fruit bats (Pteropus livingstonii), and to assess the impact on weight of enclosure space. The mean capture weight of wild-caught male Livingstone's bats was 657 g, significantly higher than that of females (544 g). In both wild and captive-born bats, males had significantly longer forearms than females, but there was no effect of birth location. Males weighed more in the mating season than at other times of year. Both sexes gained more weight during development if born in enclosures that restricted flight rather than a large aviary; this was particularly noticeable in females. After reaching maturity at 3 years, weights of bats born in restricted enclosures continued to increase, reached a peak of over 1000 g at 8-10 years, and then declined in both sexes. The weight of bats born in the aviary remained more stable after the age of three. Like wild bats, adult females born in the aviary weighed less than males. However, females born in restricted enclosures weighed more than males born in the same enclosures. Enclosure designs that maximize opportunities for flight can limit excessive weight gain in captive fruit bats and may therefore improve fitness and health, essential in planning for future reintroduction programs.

First evidence of sexual dimorphism in olfactory organs of deep-sea lanternfishes (Myctophidae).

Finding a mate is of the utmost importance for organisms, and the traits associated with successfully finding one can be under strong selective pressures. In habitats where biomass and population density is often low, like the enormous open spaces of the deep sea, animals have evolved many adaptations for finding mates. One convergent adaptation seen in many deep-sea fishes is sexual dimorphism in olfactory organs, where, relative to body size, males have evolved greatly enlarged olfactory organs compared to females. Females are known to give off chemical cues such as pheromones, and these chemical stimuli can traverse long distances in the stable, stratified water of the deep sea and be picked up by the olfactory organs of males. This adaptation is believed to help males in multiple lineages of fishes find mates in deep-sea habitats. In this study, we describe the first morphological evidence of sexual dimorphism in the olfactory organs of lanternfishes (Myctophidae) in the genus Loweina. Lanternfishes are one of the most abundant vertebrates in the deep sea and are hypothesized to use visual signals from bioluminescence for mate recognition or mate detection. Bioluminescent cues that are readily visible at distances as far as 10 m in the aphotic deep sea are likely important for high population density lanternfish species that have high mate encounter rates. In contrast, myctophids found in lower density environments where species encounter rates are lower, like those in Loweina, likely benefit from longer-range chemical or olfactory cues for finding and identifying mates.

Filling the gaps in ecology of tropical tiger beetles (Coleoptera: Cicindelidae): first quantitative data of sexual dimorphism in semi-arboreal Therates from the Philippine biodiversity hotspot.

Background: Sexual dimorphism, driven by sexual selection, leads to varied morphological distinctions in male and female insects, providing insights into selection pressures across species. However, research on the morphometric variability within specific taxa of tiger beetles (Coleoptera: Cicindelidae), particularly arboreal and semi-arboreal species, remains very limited. Methods: We investigate sexual dimorphism in six semi-arboreal Therates tiger beetle taxa from the Philippines, focusing on morphological traits. We employed morphometric measurements and multivariate analyses to reveal patterns of sexual dimorphism between sexes within the taxa. Results: Our results indicate significant sexual dimorphism in elytra width, with females consistently displaying broader elytra, potentially enhancing fecundity. Notable sexual size dimorphism was observed in Therates fulvipennis bidentatus and T. coracinus coracinus, suggesting heightened sexual selection pressures on male body size. Ecological factors, mating behavior, and female mate choice might contribute to the observed morphological variation. These findings emphasize the need for further studies to comprehend mating dynamics, mate choice, and ecological influences on morphological variations in semi-arboreal and arboreal tiger beetles.

Genetic Basis and Evolutionary Forces of Sexually Dimorphic Color Variation in a Toad-Headed Agamid Lizard.

In the animal kingdom, sexually dimorphic color variation is a widespread phenomenon that significantly influences survival and reproductive success. However, the genetic underpinnings of this variation remain inadequately understood. Our investigation into sexually dimorphic color variation in the desert-dwelling Guinan population of the toad-headed agamid lizard (Phrynocephalus putjatai) utilized a multidisciplinary approach, encompassing phenotypic, ultrastructural, biochemical, genomic analyses, and behavioral experiments. Our findings unveil the association between distinct skin colorations and varying levels of carotenoid and pteridine pigments. The red coloration in males is determined by a genomic region on chromosome 14, housing four pigmentation genes: BCO2 and three 6-pyruvoyltetrahydropterin synthases. A Guinan population-specific nonsynonymous single nucleotide polymorphism in BCO2 is predicted to alter the electrostatic potential within the binding domain of the BCO2-ß-carotene complex, influencing their interaction. Additionally, the gene MAP7 on chromosome 2 emerges as a potential contributor to the blue coloration in subadults and adult females. Sex-specific expression patterns point to steroid hormone-associated genes (SULT2B1 and SRD5A2) as potential upstream regulators influencing sexually dimorphic coloration. Visual modeling and field experiments support the potential selective advantages of vibrant coloration in desert environments. This implies that natural selection, potentially coupled with assortative mating, might have played a role in fixing color alleles, contributing to prevalence in the local desert habitat. This study provides novel insights into the genetic basis of carotenoid and pteridine-based color variation, shedding light on the evolution of sexually dimorphic coloration in animals. Moreover, it advances our understanding of the driving forces behind such intricate coloration patterns.

Beyond skeletal studies: A computational analysis of nasal airway function in climate adaptation.

OBJECTIVES: Ecogeographic variation in human nasal anatomy has historically been analyzed on skeletal morphology and interpreted in the context of climatic adaptations to respiratory air-conditioning. Only a few studies have analyzed nasal soft tissue morphology, actively involved in air-conditioning physiology. MATERIALS AND METHODS: We used in vivo computer tomographic scans of (N = 146) adult individuals from Cambodia, Chile, Russia, and Spain. We conducted (N = 438) airflow simulations during inspiration using computational fluid dynamics to analyze the air-conditioning capacities of the nasal soft tissue in the inflow, functional, and outflow tract, under three different environmental conditions: cold-dry; hot-dry; and hot-humid. We performed statistical comparisons between populations and sexes. RESULTS: Subjects from hot-humid regions showed significantly lower air-conditioning capacities than subjects from colder regions in all the three conditions, specifically within the isthmus region in the inflow tract, and the anterior part of the internal functional tract. Posterior to the functional tract, no differences were detected. No differences between sexes were found in any of the tracts and under any of the conditions. DISCUSSION: Our statistical analyses support models of climatic adaptations of anterior nasal soft tissue morphology that fit with, and complement, previous research on dry skulls. However, our results challenge a morpho-functional model that attributes air-conditioning capacities exclusively to the functional tract located within the nasal cavity. Instead, our findings support studies that have suggested that both, the external nose and the intra-facial soft tissue airways contribute to efficiently warming and humidifying air during inspiration. This supports functional interpretations in modern midfacial variation and evolution.

Sex matters in preclinical research.

International Women's Day 2024 has a theme of inclusion. As publishers of preclinical research, we aim to show how inclusion of females in research advances scientific rigor and improves treatment reliability. Sexual reproduction is key to all life across the plant and animal kingdoms. Biological sex takes many forms that are morphologically differentiated during development: stamens versus pistils in plants; color and plumage in birds; fallopian tubes versus vas deferens in mammals; and differences in size, for instance, males are smaller in the fruit fly Drosophila melanogaster. Physical differences may be obvious, but many traits may be more obscure, including hormonal, physiological and metabolic factors. These traits have a big influence on disease and responses to treatment. Thus, we call for improved inclusion, analysis and reporting of sex as a biological variable in preclinical animal modeling research.