Sex Determination Research Articles

Cardiovascular health metrics and all-cause mortality in osteoarthritis, inflammatory arthritis, and unclassified arthritis patients: a national prospective cohort study

BackgroundArthritis notably elevates mortality risk. It remains unclear whether the cardiovascular health (CVH) metrics improves the risk of all-cause mortality in patients with all types of arthritis.MethodsThis study data from the National Health and Nutrition Examination Survey to probe the link between CVH and all-cause mortality among arthritis sufferers in the United States. CVH evaluation employed the Life's Essential 8 metrics. Mortality outcomes were scrutinized using Cox proportional hazard regression models. Additionally, a restricted cubic spline analysis delineated the linear relationship between CVH and mortality. The study also delved into the singular impact of each CVH component on mortality.ResultsIn the cohort of 5919 patients with arthritis, improved CVH was linked to lower all-cause mortality. Specifically, each 10-point increment in CVH score was associated with a substantial decline in all-cause mortality risk [unadjusted hazard ratio (HR): 0.77, 95% Confidence Interval (95% CI): 0.71–0.83, P < 0.001]. Adjustments for age, sex, race, and social determinants of health further refined the HR to 0.72 (95% CI: 0.67–0.79, P < 0.001). Higher versus lower CVH scores at baseline markedly reduced mortality risk, with the most substantial decrease seen in those with ideal CVH metrics (HR: 0.39, 95% CI: 0.26–0.59, P < 0.001). Similar results were not observed in patients with inflammatory arthritis, but were seen in those with osteoarthritis or degenerative arthritis, and unknown types of arthritis.ConclusionIdeal CVH substantially decreases all-cause mortality risk among patients with arthritis, confirming the critical role of CVH in arthritis management. This study advocates for CVH interventions as part of comprehensive arthritis treatment plans.

Sex determination and odontometric dimensions - A study of a North Indian population.

Sex determination is an indispensable parameter in identifying unknown deceased individuals. It can narrow down the chances of possible matches by 50%, providing a crucial lead in personal identification. In cases of commingled, decomposed, fragmented, charred and unidentifiable corpses, the importance of dental morphometrics cannot be overlooked due to the resistance of teeth to post-mortem degradation. Addressing this quality of teeth, a descriptive cross-sectional study was conducted in a North Indian population to evaluate sexual variations in dental dimensions and to identify the most sexually dimorphic dental dimension. The study included 207 participants (114 females and 93 males) in the age group of 21 to 45 years. Dental casts were prepared after obtaining informed consent from the participants and ethical clearance from the institute's ethical committee. Six odontometric dimensions, namely incisor-incisor distance, inter canine distance, combined width of central incisors, inter-premolar distance, inter-molar distance, and dental arch height of each participant were recorded on the dental casts using standard procedures. Analysis of the data elucidated the existence of statistically significant sexual dimorphism in the dental dimensions of the participants. The results of the discriminant function analysis show a sex determination accuracy of 68.1%, with a cross-validation accuracy of 65.2%. The study found the incisor-incisor distance to be the most sexually dimorphic trait, making it the best predictor of sex in the present population. The results of the present study may be helpful in sex determination and personal identification from dental remains in medico-legal and disaster victim identification cases.

Frequencies of house fly proto-Y chromosomes across populations are predicted by temperature heterogeneity within populations.

Sex chromosomes often differ between closely related species and can even be polymorphic within populations. Species with multifactorial sex determination segregate for multiple different sex determining loci within populations, making them uniquely informative of the selection pressures that drive the evolution of sex chromosomes. The house fly (Musca domestica) is a model species for studying multifactorial sex determination because male determining genes have been identified on all six of the chromosomes, which means that any chromosome can be a "proto-Y". Natural populations of house fly also segregate for a recently derived female-determining locus, meaning house flies also have a proto-W chromosome. The different proto-Y chromosomes are distributed along latitudinal clines on multiple continents, their distributions can be explained by seasonality in temperature, and they have temperature-dependent effects on physiological and behavioral traits. It is not clear, however, how the clinal distributions interact with the effect of seasonality on the frequencies of house fly proto-Y and proto-W chromosomes across populations. To address this question, we measured the frequencies of house fly proto-Y and proto-W chromosomes across nine populations in the United States of America. We confirmed the clinal distribution along the eastern coast of North America, but it is limited to the eastern coast. In contrast, annual mean daily temperature range predicts proto-Y chromosome frequencies across the entire continent. Our results therefore suggest that temperature heterogeneity can explain the distributions of house fly proto-Y chromosomes in a way that does not depend on the cline.

Identification of sex-specific markers using genome re-sequencing in the blunt snout bream (Megalobrama amblycephala)

BackgroundThe blunt snout bream (Megalobrama amblycephala) is an important economic freshwater fish in China with tender flesh and high nutritional value. With the cultivation of superior new varieties and the expansion of breeding scale, it becomes imperative to employ sex-control technology to cultivate monosexual populations of M. amblycephala, thereby preventing the deterioration of desirable traits. The development of specific markers capable of accurately identifying the sex of M. amblycephala would facilitate the determination of the genetic sex of the breeding population before gonad maturation, thereby expediting the processes of sex-controlled breeding of M. amblycephala.ResultsA whole-genome re-sequencing was performed for 116 females and 141 males M. amblycephala collected from nine populations. Seven candidate male-specific sequences were identified through comparative analysis of male and female genomes, which were further compared with the sequencing data of 257 individuals, and finally three male-specific sequences were generated. These three sequences were further validated by PCR amplification in 32 males and 32 females to confirm their potential as male-specific molecular markers for M. amblycephala. One of these markers showed potential applicability in M. pellegrini as well, enabling males to be identified using this specific molecular marker.ConclusionsThe study provides a high-efficiency and cost-effective approach for the genetic sex identification in two species of Megalobrama. The developed markers in this study have great potential in facilitating sex-controlled breeding of M. amblycephala and M. pellegrini, while also contributing valuable insights into the underlying mechanisms of fish sex determination.

The debate on artificial insemination in medical-moral reflection in Italy over the last decade

Talking today about artificial insemination certainly no longer arouses wonder. Man's lordship over creation, in fact, registers a singular breadth with unprecedented and surprising results, especially in the field of the physio-pathology of reproduction: intrauterine diagnosis of genetic diseases, control or even sex determination, the most diverse genetic experiments for therapeutic or research purposes; attempts at extracorporeal fertilisation.

Genome Survey of Male Rana dybowskii to Further Understand the Sex Determination Mechanism.

Rana dybowskii is one of the important aquaculture species in Northeast China. The fallopian tubes of female R. dybowskii are used to prepare oviductus ranae (an important traditional Chinese medicine). Therefore, R. dybowskii females have higher economical value than males. An increasing female R. dybowskii population can increase the benefits from R. dybowskii culture. However, the genome of amphibians is complex, making it difficult to investigate their sex determination mechanism. In this study, we analyzed the genome of male R. dybowskii using next-generation sequencing technology. A total of 200,046,452,400 bp of clean data were obtained, and the K-mer analysis indicated that the depth was 50×. The genome size of R. dybowskii was approximately 3585.05 M, with a heterozygosity rate, repeat sequence ratio, and genome GC content of 1.15%, 68.96%, and approximately 43.0%, respectively. In total, 270,785 contigs and 498 scaffolds were generated. The size of the contigs and scaffolds was 3,748,543,415 and 3,765,862,278 bp, respectively, with the N50 length of 31,988 and 336,385,783. The longest contig and scaffold were of the size 137,967,485 and 1,808,367,828 bp, respectively. The number of contigs and scaffolds > 10K nt was 99,620 and 451, respectively. Through annotation, 40,913 genes were obtained, including 156,609 CDS (i.e., 3.83 CDS per gene). Sequence alignment was performed with the assembled scaffolding genome in this study. Two and one fragment had high homology with two male-specific DNA molecular markers of R. dybowskii discovered previously (namely, MSM-222 and MSM-261, respectively). In addition, the Dmrt1 gene of R. dybowskii was obtained with a length of 18,893 bp by comparison and splicing. The forward primers amplifying MSM-222 and MSM-261 were located at 322-343 and 14,501-14,526 bp of Dmrt1, respectively. However, sequence alignment revealed that MSM-222 and MSM-261 were not located on Dmrt1, and only some homologous parts were observed. This indicated that in addition to Dmrt1, other important genes may play a crucial role in the sex determination mechanism of R. dybowskii. Our study provided a foundation for the subsequent high-quality genome construction and provided important genomic resources for future studies on R. dybowskii.

Differences in Growth Performance and Meat Quality between Male and Female Juvenile Nile Tilapia (Oreochromis niloticus) during Separate Rearing.

This study compared the growth and flesh quality of juvenile male and female Nile tilapia grown in separate RAS tanks. The Genetic Sex Determination method yielded 40 males and 40 females. Males grew longer and heavier than females, and the results showed significant variation between the sexes in terms of weight gain rate (WGR), specific growth rate (SGR), and final body length and weight. In terms of the feed conversion ratio (FCR), Gonad Somatic Index (GSI), and Viscera Somatic Index (VSI), females presented better results than males. Male and female Hepatosomatic Index (HSI) values did not differ significantly-no difference in blood serum values. The meat's moisture and crude protein composition did not alter significantly from male to female; however, the crude fat and ash levels did differ significantly. Male and female animals were given the same seventeen distinct types of amino acids, and there was no distinct variation in the profiles of total amino acids (TAAs) and essential amino acids (EAAs) between the sexes. However, in the non-essential amino acid (NEAA) category, there were marginally significant differences, wherein females performed better than males. Males and females differed considerably in crude fat and ash levels but not in the moisture content or crude protein composition of the meat. Regarding fatty acids, males outperformed females in terms of total fatty acids (TFAs), polyunsaturated fatty acids (PUFAs), and saturated fatty acids (SFAs). However, no significant difference in the amount of monounsaturated fatty acids (MUFAs) in muscle was found between males and females.

Male is the default sex: functional significance of the sex determination cascade in horned dung beetles.

Sex-specific trait expression represents a striking dimension of morphological variation within and across species. The mechanisms instructing sex-specific organ development have been well studied in a small number of insect model systems, suggesting striking conservation in some parts of the somatic sex determination pathway while hinting at possible evolutionary lability in others. However, further resolution of this phenomenon necessitates additional taxon sampling, particularly in groups in which sexual dimorphisms have undergone significant elaboration and diversification. Here, we functionally investigate the somatic sex determination pathway in the gazelle dung beetle Digitonthophagus gazella , an emerging model system in the study of the development and evolution of sexual dimorphisms. We find that RNA interference (RNAi) targeting transformer1 (tra1) caused chromosomal females to develop morphological traits largely indistinguishable from those normally only observed in males, and that tra1 RNAi is sufficient to induce splicing of the normally male-specific isoform of doublesex in chromosomal females, while leaving males unaffected. Further, intersex RNAi was found to phenocopy previously described RNAi phenotypes of doublesex in female but not male beetles. These findings match predictions derived from models of the sex determination cascade as developed largely through studies in Drosophila melanogaster . In contrast, transformer2 RNAi resulted in larval mortality and was not sufficient to affect doublesex splicing, whereas RNAi targeting Sex-lethal and two putative orthologs of hermaphrodite yielded no obvious phenotypic modifications in either males or females, raising the possibility that the function of a subset of sex determination genes may be derived in Diptera and thus non-representative of their roles in other holometabolous orders. Our results help illuminate how the differential evolutionary lability of the somatic sex determination pathway has contributed to the extraordinary morphological diversification of sex-specific trait expression found in nature.

Genome-Wide Association Studies (GWAS) and Transcriptome Analysis Reveal Male Heterogametic Sex-Determining Regions and Candidate Genes in Northern Snakeheads (Channa argus).

The Northern snakehead (Channa argus) is a significant economic aquaculture species in China. Exhibiting sexual dimorphism in the growth rate between females and males, mono-sex breeding holds substantial value for aquaculture. This study employed GWAS and transcriptome analysis were applied to identify sex determination genomic regions and develop sex-specific markers. A total of 270 single-nucleotide polymorphisms (SNPs) and 31 insertion-deletions (InDels) were identified as being sexually dimorphic through GWAS and fixation index (Fst) scanning. Based on GWAS results, two sex-specific InDel markers were developed, effectively distinguishing genetic sex for XX females, XY males, and YY super-males via (polymerase chain reaction) PCR amplification. A major genomic segment of approximately 115 kb on chromosome 3 (Chr 03) was identified as the sex-determination region. A comparative transcriptome analysis of gonads for three sexes identified 158 overlapping differentially expressed genes (DEGs). Additionally, three sex-related candidate genes were identified near the sex determination region, including id2, sox11, and rnf144a. Further studies are required to elucidate the functions of these genes. Overall, two sex-specific InDel markers support a male heterogametic XX/XY sex-determination system in Northern snakeheads and three candidate genes offer new insights into sex determination and the evolution of sex chromosomes in teleost fish.

Identification of two effective sex-specific DNA markers in silver arowana (Osteoglossum bicirrhosum)

The silver arowana (Osteoglossum bicirrhosum), often referred to as a living fossil, presents significant challenges in sex identification based on morphological characteristics, with its sex determination mechanism remaining poorly understood. This issue poses considerable obstacles to its captive breeding efforts. Given the species' substantial value for both consumption and ornamental purposes, it is a critical candidate for aquaculture. Through genome sequencing, read mapping, and alignment analysis of five male and five female silver arowanas, along with one mixed pool of males, we successfully identified two sex-specific SNPs and confirmed a ZW model of sex determination in this ancient species. These two SNPs demonstrated remarkable accuracy, achieving 100 % success in genetic sex identification, as validated by Sanger sequencing of PCR products from 135 individuals. Both sex-specific SNPs are located approximately 26 kb upstream of the foxl2 gene, indicating a potentially pivotal role for the foxl2 gene in the sex-determination process of the silver arowana. Consequently, we have developed precise molecular markers for sex identification in the silver arowana, significantly enhancing reproductive efficiency and promoting further industrial development. This achievement lays a foundational basis for investigating the sex-determination mechanism of the silver arowana and other osteoglossid fish, thereby advancing aquaculture practices within this species.

Integrative morphological, cytogenetic and molecular characterization of the Andean climbing catfish Astroblepus mindoensis (Regan, 1916) (Siluriformes:Astroblepidae).

Astroblepus species, commonly known as Andean climbing catfish, exhibit a unique challenge in species delimitation, leading to ongoing taxonomic debates. Here we report data on Astroblepus mindoensis, a vulnerable species endemic to Ecuador, obtained by an integrative approach that includes cytogenetic analysis, molecular identification of the specimens, and recording of morphological and morphometric characters useful for species diagnosis. Thus, this study aimed to associate the karyotype data of the specimens analyzed with morphological and molecular characters, improving and expanding the existing taxonomic information, thus contributing to the systematics of the species. Our morphology results, unlike Regan's original description, which is brief and ambiguous, provide a more detailed morphometric and meristic description. Molecular phylogenetic reconstruction and genetic distance based on a fragment of the cytochrome c oxidase subunit I (COI) showed that our samples constitute a well-supported and monophyletic clade within the A. grixalvii species complex. The cytogenetic analysis identified distinct chromosomal markers, including a single cluster of major ribosomal genes (on chromosome pair 3) and of minor ribosomal genes (on chromosome pair 12) with their localization differing from those reported in other Astroblepus species analyzed. Additionally, the presence of a heteromorphic chromosome pair in males suggests the presence of an XX/XY sex-determination system that has not been identified in other congeneric species. Further investigation is necessary to determine if these chromosomes are associated with the accumulation of repeated sequences, as typically occurs with sex chromosomes, and to assess their presence in other species of the genus.

Molecular and genetic mechanisms of sex determination in poplar

The study of molecular and genetic mechanisms of sex determination in poplar is of interest not only in the fundamental aspect, but also in the applied aspect. In landscaping of large settlements, it is advisable to use male individuals of Populus genus due to their hypoallergenicity and increased resistance to environmental pollution, stress conditions and pathogens. However, sex determination in poplars is complicated by the complex genetic structure of the sex-determining region of the genome (SDR). In this review, the emergence, evolution, structure and function of the SDR in the genus Populus are discussed. Current insights into the structure and function of the key regulator of sex selection in poplars, the orthologous ARR16/ARR17 gene, and the possible role of other genes differentially expressed between male and female plants, including microRNAs, in this process are discussed in detail. The great diversity of species and the high complexity of SDR organization justify the need for further study of the molecular mechanisms of sex determination in poplars.

Poly(A)-Specific Ribonuclease Deficiency Leads to Deregulated Expression of Genes Involved in Sex Determination and Gonadal Maturation in Zebrafish

Abstract Background Deadenylation, the process of removal of poly (A) tail of messenger ribonucleic acids (mRNAs), is a rate-limiting step in mRNA stability, and poly(A)-specific ribonuclease (PARN) is the most important exonuclease involved in this process. Besides mRNA stability, PARN is also involved in several other processes including telomere maintenance, noncoding RNA maturation, ribosome biogenesis, and TP53 function. Previously, we have shown that zebrafish PARN null mutants are viable and fertile but turn out to only develop into males, indicating a role in oogenesis. The present study was focused on analyzing the expression of genes involved in sex determination and gonadal development in PARN mutant zebrafish. Materials and Methods Total RNA was extracted and quantitative real-time polymerase chain reaction was performed to determine the expression level of genes involved in gonad development in PARN mutant embryos (4 days postfertilization [dpf]) and adults (120 dpf) in comparison to their wild-type siblings. The expression levels were estimated by the ΔΔCT relative quantification method. Results At 4 dpf, the expression of germ cell-specific genes did not show any significant difference in the null mutants compared to the heterozygous and their wild-type siblings, suggesting no effect on germ cell differentiation due to the loss of PARN. However, the majority of the ovary-associated genes analyzed showed an increased expression in PARN null and heterozygous mutants compared to the wild-type siblings. Intriguingly, the expression of testis-associated genes showed decreased expression in the mutants compared to their wild-type siblings at 4 dpf. In adult stages, as expected, the expression of genes that jointly regulate the proper formation and function of ovaries and testes showed decreased expression in PARN null mutants. Interestingly, the expression of genes involved in the differentiation of testes, despite showing a decreased expression in the mutants, was comparable between the null and heterozygous mutants. Conclusion Taken together, these results suggest that the loss of PARN does not affect germ cell differentiation but affects the sexual differentiation that happens at later stages of development, particularly the process of oogenesis, in zebrafish.

Amelogenin-Based Molecular Methods for Sexual Dimorphism Identification: Protocol of a Scoping Review

Forensic dentistry and sexual dimorphism are distinct concepts. Still, they are related due to the usefulness that the first may have in the second, and this review focuses on them. A scoping review will be performed according to the Joanna Briggs Institute’s methodology. Scientific databases and grey literature will be used, and the following keywords will be applied: amelogenin, analyses, sex determination, and human identification. This scoping review will include in vitro studies concerning the goal of this review. This scoping review will deepen our knowledge concerning using teeth and amelogenin genes in sex identification in a forensic context. According to the available data, it will help implement guidelines for human remains identification. This protocol was registered with the Open Science Framework.

Genome-Wide Identification and Expression Analysis of the BTB Gene Superfamily Provides Insight into Sex Determination and Early Gonadal Development of Alligator sinensis.

The BTB gene superfamily is widely distributed among higher eukaryotes and plays a significant role in numerous biological processes. However, there is limited knowledge about the structure and function of BTB genes in the critically endangered species Alligator sinensis, which is endemic to China. A total of 170 BTB genes were identified from the A. sinensis genome, classified into 13 families, and unevenly distributed across 16 chromosomes. Analysis of gene duplication events yielded eight pairs of tandem duplication genes and six pairs of segmental duplication genes. Phylogenetics shows that the AsBTB genes are evolutionarily conserved. The cis-regulatory elements in the AsBTB family promoter region reveal their involvement in multiple biological processes. Protein interaction network analysis indicates that the protein interactions of the AsBTB genes are centered around CLU-3, mainly participating in the regulation of biological processes through the ubiquitination pathway. The expression profile and protein interaction network analysis of AsBTB genes during sex differentiation and early gonadal development indicate that AsBTB genes are widely expressed in this process and involves numerous genes and pathways for regulation. This study provides a basis for further investigation of the role of the BTB gene in sex differentiation and gonadal development in A. sinensis.

Beyond the binary female/male sex classification: The impact of (trans)gender on the identification of human remains.

In cases of unidentified deceased persons, sex determination is a routine task in forensic medicine. However, the binary biological sex categories 'female' and 'male' may be challenged if it is not clear whether the information in the missing persons databases refers to the biological sex or the (felt and lived) gender. An umbrella term for people who do not identify with their birth sex (which usually is the biological, chromosomal sex) is 'transgender'. In recent decades, the legal and social situation of transgender people has changed in many countries making it easier to live their felt gender more openly. This development highlights the issue of potential challenges in the postmortem identification of transgender individuals. Serious problems in corresponding cases may be rare-but they must be considered and addressed in forensic practice to minimize the risk of delayed or failed identification. The impact of (trans)gender on the identification of human remains was examined by a narrative literature review under special consideration of the prevalences of transgender identities in general populations and in the group of unidentified deceased; possible actions to avoid problems in the postmortem identification of transgender persons in forensic practice are being proposed. One can assume that 1 of 200 people in the United States, the European Union and comparable societies is transgender with an opposite-sex identification, and 2 to 3 of 100 people live outside the typical female/male binary, with numbers increasing. If legally possible, an increasing number of transgender individuals will change their name and gender in civil registration. Transgender individuals are likely to be overrepresented in suicides and in victims of homicides. Although there are no precise data on the prevalence of transgender individuals in the group of unidentified deceased, the remarkably high reported prevalence in the general population and the over-representation of transgender individuals in suicides and homicides suggest that the topic is relevant to forensic practice. An autopsy does not always provide evidence of transgender identity, for example in skeletal remains. Particularly in unsolved cases, the possibility that an unidentified person may have been transgender should be considered. Knowledge and awareness of forensic practitioners on this topic should be strengthened by research and training. Databases and data reporting should be optimized. Recording in antemortem databases should clearly distinguish between 'biological sex' and 'apparent sex /lived gender identity'. When collecting postmortem data, a clear distinction should be made between "chromosomal sex" and "sex based on morphological findings". CLINICAL TRIAL NUMBER: Not applicable (review article).

Sharp decline in male fertility in F2 hybrids of the female-heterogametic silk moth Bombyx.

Sexual selection drives rapid evolution of morphological, physiological, and behavioral traits, especially in males, and it may also drive the rapid evolution of hybrid male sterility. Indeed, the faster male theory of speciation was once viewed as a major cause of Haldane's rule in male-heterogametic XY taxa, but is increasingly being replaced by the genetic conflict hypothesis partly because it cannot explain the faster evolution of hybrid female sterility in female-heterogametic ZW taxa. The theory nonetheless predicts that there should be more genes for hybrid male sterility than for hybrid female sterility even in such taxa, but this remains untested. Thus, finding evidence for the faster male theory of reproductive isolation beyond the F1 generation in ZW systems still represents a challenge to studying the impact of sexual selection. In this study, we examined F2 hybrids between the domesticated silkworm Bombyx mori and the wild silk moth Bombyx mandarina, which have ZW sex determination. We found that although only females showed reduced fertility in the F1 generation, the F2 hybrid males had a significant reduction in fertility compared with the parental and F1 males. Importantly, 27% of the F2 males and 15% of the F2 females were completely sterile, suggesting the presence of recessive incompatibilities causing male sterility in female-heterogametic taxa.

8053 A Ligand-Based Differentiation Protocol for Human Induced Pluripotent Stem Cells Recapitulates Granulosa Cell Development and Induces Steroidogenic Pathway Genes

Abstract Disclosure: H. Kubo: None. M.M. Laronda: None. Sex determination is a developmental process that defines the gonad as a testis or ovary, and influences sex hormone production. While key signaling events are well conserved across mammals, there can be differences between species. Therefore, there is a need to develop a human model to fully understand this critical process in humans. We have developed a ligand-based differentiation protocol for human induced pluripotent stem cells (hiPSCs) to generate granulosa-like cells (GLCs). Additionally, hiPSC-derived GLCs could become the foundation for a cell-based hormone replacement therapy that recapitulates cyclicity, physiologic levels of hormones, and production of peptide hormones that are not included in currently available hormone replacement therapies. We aim to gain further understanding of the key factors and culture conditions necessary for functional GLCs that produce ovarian hormones, which includes maintained expression of FOXL2. We used our monolayer differentiation protocol that includes WNT-agonist CHIR99021 treatment for 2 days, followed by a combination treatment of BMP4, FST, and DKK1-inhibitor Gallocyanine for 3 days. We have tested our protocol on three different hiPSC lines: IISH2i-BM9s, STiPS-A3, and STiPS-A6. Expression of pluripotency marker POU5F1 is reduced during differentiation, while expression of the intermediate mesoderm markers PAX2, LHX1, and WT1 and bipotential gonad marker GATA4 peak at day 2. Peak expression of the bipotential gonad marker NR5A1 occurred at day 2 in the STiPS-A6 cells, but at day 5 in IISH2i-BM9 and STiPS-A3 cells. Interestingly, FOXL2 expression peaks at day 2 in all three lines and drops by day 5. In the IISH2i-BM9s, FOXL2 protein peaks at day 2 by Jess Western while there is the highest percentage of FOXL2-positive cells at day 5 by immunofluorescence. In murine granulosa cells, FOXL2 maintenance depends on NR5A2. NR5A2 expression drops in the GLCs, which suggests that NR5A2 loss may be preventing FOXL2 maintenance. Additionally, as FOXL2 is required for expression of aromatase and HSD17B1, we are using this model to interrogate NR5A2 upstream of FOXL2 and control hormone production. CYP19A1 and HSD17B1 along with AMH are induced during this differentiation protocol, suggesting these GLCs can be steroidogenic and produce peptide hormones. Additionally, scRNA-seq analysis of the GLCs is underway to identify types of granulosa cells produced by this protocol. Future directions include optimizing GLC culture conditions to generate hormones and to test if NR5A2 inhibitors alter FOXL2 expression. Put together, the data suggests that cells differentiated with our protocol show promise as a human model of ovarian development and a foundation for a personalized cell-based hormone replacement therapy. This work is supported by the NIH/NICHD R01HD104683 (MML), HuBMAP U01HD110336 (MML), and Gesualdo Family Research Scholar (MML). Presentation: 6/2/2024

Comparative analysis of amphibian genomes: An emerging resource for basic and applied research.

Amphibians are the most threatened group of vertebrates and are in dire need of conservation intervention to ensure their continued survival. They exhibit unique features including a high diversity of reproductive strategies, permeable and specialized skin capable of producing toxins and antimicrobial compounds, multiple genetic mechanisms of sex determination and in some lineages, the ability to regenerate limbs and organs. Although genomic approaches would shed light on these unique traits and aid conservation, sequencing and assembly of amphibian genomes has lagged behind other taxa due to their comparatively large genome sizes. Fortunately, the development of long-read sequencing technologies and initiatives has led to a recent burst of new amphibian genome assemblies. Although growing, the field of amphibian genomics suffers from the lack of annotation resources, tools for working with challenging genomes and lack of high-quality assemblies in multiple clades of amphibians. Here, we analyse 51 publicly available amphibian genomes to evaluate their usefulness for functional genomics research. We report considerable variation in genome assembly quality and completeness and report some of the highest transposable element and repeat contents of any vertebrate. Additionally, we detected an association between transposable element content and climatic variables. Our analysis provides evidence of conserved genome synteny despite the long divergence times of this group, but we also highlight inconsistencies in chromosome naming and orientation across genome assemblies. We discuss sequencing gaps in the phylogeny and suggest key targets for future sequencing endeavours. Finally, we propose increased investment in amphibian genomics research to promote their conservation.

The Amphibian Genomics Consortium: advancing genomic and genetic resources for amphibian research and conservation.

Amphibians represent a diverse group of tetrapods, marked by deep divergence times between their three systematic orders and families. Studying amphibian biology through the genomics lens increases our understanding of the features of this animal class and that of other terrestrial vertebrates. The need for amphibian genomic resources is more urgent than ever due to the increasing threats to this group. Amphibians are one of the most imperiled taxonomic groups, with approximately 41% of species threatened with extinction due to habitat loss, changes in land use patterns, disease, climate change, and their synergistic effects. Amphibian genomic resources have provided a better understanding of ontogenetic diversity, tissue regeneration, diverse life history and reproductive modes, antipredator strategies, and resilience and adaptive responses. They also serve as essential models for studying broad genomic traits, such as evolutionary genome expansions and contractions, as they exhibit the widest range of genome sizes among all animal taxa and possess multiple mechanisms of genetic sex determination. Despite these features, genome sequencing of amphibians has significantly lagged behind that of other vertebrates, primarily due to the challenges of assembling their large, repeat-rich genomes and the relative lack of societal support. The emergence of long-read sequencing technologies, combined with advanced molecular and computational techniques that improve scaffolding and reduce computational workloads, is now making it possible to address some of these challenges. To promote and accelerate the production and use of amphibian genomics research through international coordination and collaboration, we launched the Amphibian Genomics Consortium (AGC, https://mvs.unimelb.edu.au/amphibian-genomics-consortium) in early 2023. This burgeoning community already has more than 282 members from 41 countries. The AGC aims to leverage the diverse capabilities of its members to advance genomic resources for amphibians and bridge the implementation gap between biologists, bioinformaticians, and conservation practitioners. Here we evaluate the state of the field of amphibian genomics, highlight previous studies, present challenges to overcome, and call on the research and conservation communities to unite as part of the AGC to enable amphibian genomics research to "leap" to the next level.