Streamlined identification of clinically and functionally relevant genetic regulators of lower-tract urogenital development.

Congenital anomalies of the lower genitourinary (LGU) tract are frequently comorbid due to genetically linked developmental pathways, and are among the most common yet most socially stigmatized congenital phenotypes. Genes involved in sexual differentiation are prime candidates for developmental anomalies of multiple LGU organs, but insufficient prospective screening tools have prevented the rapid identification of causative genes. Androgen signaling is among the most influential modulators of LGU development. The present study uses SpDamID technology in vivo to generate a comprehensive map of the pathways actively regulated by the androgen receptor (AR) in the genitalia in the presence of the p300 coactivator, identifying wingless/integrated (WNT) signaling as a highly enriched AR-regulated pathway in the genitalia. Transcription factor (TF) hits were then assayed for sexually dimorphic expression at two critical time points and also cross-referenced to a database of clinically relevant copy number variations to identify 252 TFs exhibiting copy variation in patients with LGU phenotypes. A subset of 54 TFs was identified for which LGU phenotypes are statistically overrepresented as a proportion of total observed phenotypes. The 252 TF hitlist was then subjected to a functional screen to identify hits whose silencing affects genital mesenchymal growth rates. Overlap of these datasets results in a refined list of 133 TFs of both functional and clinical relevance to LGU development, 31 of which are top priority candidates, including the well-documented renal progenitor regulator, Sall1. Loss of Sall1 was examined in vivo and confirmed to be a powerful regulator of LGU development.

Rapid divergent evolution of internal female genitalia and the coevolution of male genital morphology revealed by micro-computed tomography.

Animal genitalia are thought to evolve rapidly and divergently in response to sexual selection. Studies of genital evolution have focused largely on male genitalia. The paucity of work on female genital morphology is probably due to problems faced in quantifying shape variation, due to their composition and accessibility. Here we use a combination of micro-computed tomography, landmark free shape quantification and phylogenetic analysis to quantify the rate of female genital shape evolution among 29 species of Antichiropus millipedes, and their coevolution with male genitalia. We found significant variation in female and male genital shape among species. Male genital shape showed a stronger phylogenetic signal than female genital shape, although the phylogenetic signal effect sizes did not differ significantly. Male genital shape was found to be evolving 1.2 times faster than female genital shape. Female and male genital shape exhibited strong correlated evolution, indicating that genital shape changes in one sex are associated with corresponding changes in the genital shape of the other sex. This study adds novel insight into our growing understanding of how female genitalia can evolve rapidly and divergently, and highlights the advantages of three-dimensional techniques and multivariate analyses in studies of female genital evolution.

A molecular phylogeny of the Petaluridae (Odonata: Anisoptera): A 160-Million-Year-Old story of drift and extinction.

Petaluridae (Odonata: Anisoptera) is a relict dragonfly family, having diverged from its sister family in the Jurassic, of eleven species that are notable among odonates (dragonflies and damselflies) for their exclusive use of fen and bog habitats, their burrowing behavior as nymphs, large body size as adults, and extended lifespans. To date, several nodes within this family remain unresolved, limiting the study of the evolution of this peculiar family. Using an anchored hybrid enrichment dataset of over 900 loci we reconstructed the species tree of Petaluridae. To estimate the temporal origin of the genera within this family, we used a set of well-vetted fossils and a relaxed molecular clock model in a divergence time estimation analysis. We estimate that Petaluridae originated in the early Cretaceous and confirm the existence of monophyletic Gondwanan and Laurasian clades within the family. Our relaxed molecular clock analysis estimated that these clades diverged from their MRCA approximately 160 mya. Extant lineages within this family were identified to have persisted from 6 (Uropetala) to 120 million years (Phenes). Our biogeographical analyses focusing on a set of key regions suggest that divergence within Petaluridae is largely correlated with continental drift, the exposure of land bridges, and the development of mountain ranges. Our results support the hypothesis that species within Petaluridae have persisted for tens of millions of years, with little fossil evidence to suggest widespread extinction in the family, despite optimal conditions for the fossilization of nymphs. Petaluridae appear to be a rare example of habitat specialists that have persisted for tens of millions of years.

45,X/46,XY mosaicism: Clinical manifestations and long term follow-up.

45,X/46,XY chromosomal mosaicism presents a range of clinical manifestations, including phenotypes from Turner syndrome through genital abnormalities to apparently unaffected phenotypic males; however, the full clinical spectrum has not yet been fully delineated since prior studies on the clinical phenotype and associated risk of gonadal tumors included small cohorts and limited follow-up. To better describe the clinical manifestations and long-term outcome of patients with 45,X/46,XY mosaicism. We conducted a retrospective chart review of patients with 45,X/46,XY from three health centers (Hospital for Sick Children and Mount Sinai Hospital in Canada, and University of Pittsburgh Medical Center in United States). Of 100 patients with 45,X/46,XY karyotype, 47 were raised as females and 53 as males. Females were significantly shorter than males (p = 0.04) and height Z-score was significantly decreased with age for both genders (p = 0.02). Growth hormone (GH) treatment did not result in a significant height increase compared to the untreated group (p = 0.5). All females required puberty induction in contrast to majority of males. Five females were diagnosed with gonadal tumors, while no males were affected. Around 58% of patients exhibited at least one Turner syndrome stigmata. This study expands the clinical spectrum, long-term outcomes, and associated tumor risk in a large cohort of patients with 45,X/46,XY mosaicism. Additionally, it highlights our experience with GH therapy and prophylactic gonadectomy.

Keloids in male genitalia-Systematic review and illustrative case report.

Keloid is the maximum expression of pathological fibroproliferative skin wound healing, whose pathophysiology is not yet fully understood. Its occurrence in the perineum and genitalia is uncommon. A systematic review was carried out regarding the occurrence and treatment of keloids on the penis. An illustrative case was also reported. The review used the PRISMA checklist and was registered in PROSPERO. The entire literature period up to April 2023 was searched in the EMBASE/Elsevier, Cochrane, Scopus, Medline, BVS, SciELO, and Lilacs databases. The inclusion criteria embraced primary studies, clinical trials, prospective or retrospective cohorts, case series, case-control studies and case reports. Three hundred and sixty-one studies were found and 12 of them were included, consisting of 9 case reports and 3 case series. The most common triggering factor for keloid formation was circumcision, in 11 of the cases, of which more than half occurred in prepubescent children. Several therapies, associated or isolated, were used to treat the cases. Only one of the reported patients had scar recurrence after surgical treatment. Studies with better scientific evidence are needed to understand the involvement of keloids in male genitalia. However, keloid formation in this topography is rare, making it difficult to carry out more elaborate studies.

Observations on the anatomy of the funiculus spermaticus and the testis in Brachyteles sp. (SPIX, 1823) primates - Atelidae.

BACKGROUND: Analysing the literature about the reproductive anatomy on New World Primates, one can see the need of standardisation on the description methods and, more importantly, the lack of detailed information. The problem is aggravated by the difficult access to specimens of the endangered species such as Brachyteles sp. This paper's objective was to extend knowledge on the male reproductive anatomy of these primates. The testis and funiculus spermaticus of Brachyteles are described in detail. METHODS: We utilised one individual of Brachyteles arachnoides, two hybrids (B. arachnoides × Brachyteles hypoxanthus) and photographs of the testis of a third fresh specimen of a hybrid individual. RESULTS: The septum formed by tunica dartos adheres to the testis and separates the scrotum in two testicular cavities. Passed the spermatic cord, the external spermatic fascia continues with the tunica dartos, covering the cranial half of the testis. The fascia cremasterica divides itself in bundles of fibres and forms loops around the testicles creating a sac like structure that seems to be unique among Neotropical Primates. The appendix testis is described for the first time in platyrrhini. It is presented as a sessile structure in the extremitas capitata of the testis. Previous literature on the reproductive anatomy of platyrrhini is limited. Despite that, it can be said that the large size and volume of the testis, and complex structure of the cremaster, could consist of a heat loss reduction strategy in cold and humid forest environments. CONCLUSIONS: Except for the larger size of the testicles in hybrid individuals, no other significant morphological differences were found between B. arachnoides and hybrids (B. arachnoides × B. hypoxanthus).

Discovery of a novel ejaculation mechanism in danceflies (Diptera: Empididae), with implications for genital elongation.

Genitalia are known to evolve rapidly and are among the most variable structures in insect morphology, making them a target of active research. However, function and evolutionary significance of internal genital structures remain less well understood. Here, we report the morphology and mechanism of a novel ejaculatory system that has evolved in the dancefly genus Rhamphomyia (Insecta: Diptera: Empididae). Using synchrotron µCT technology, we examined the male genitalia of five dancefly species and identified an ejaculatory system resembling a leverage hydraulic jack, which is thought to have derived from a plunger-like pumping system. This jacking system amplifies the applied muscle power by up to 4.2 times, allowing the system to produce the same pumping power with much smaller muscles. However, the volume of the pumping muscle in the jacking system is comparable to that of the plunger system, indicating a significant increase in ejaculation power in this genus. We hypothesize that the greater pumping power evolved through sexual selection favoring strong ejaculation to rapidly pass semen through a thin and elongated phallus and spermathecal duct.

Development of external genitalia during mini-puberty: is it related to somatic growth or reproductive hormones?

Although hypothalamo-pituitary-gonadal axis is active during mini-puberty, its relationship with somatic growth and the role on the development of external genitalia has not been fully elucidated. We aimed to evaluate the effects of somatic growth and reproductive hormones on the development of external genitalia during mini-puberty. Anthropometric data, pubertal assesment, serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), dehydroepiandrosterone sulfate (DHEAS), androstenedione (A4), sex-hormone binding globulin (SHBG), estradiol (E2) and inhibin-B, testosterone (T), and anti-Mullerian Hormone (AMH) of healthy infants aged 1-4 months were evaluated. Free sex hormone index was calculated as T/SHBG for boys and E2/SHBG for girls. The mean age of 148 (74 female) infants included in the study was 2.31 ± 0.76 months. Tanner stage 2-3 sex steroid and gonadotropin levels were observed. A statistically significant difference was found between the weight, height, BMI, weight gain and serum FSH, LH, and A4 measurements of girls and boys (p < 0.05). Penile length was associated with weight (r = 0.24, p = 0.03), height (r = 0.25, p = 0.02), and AMH (r = 0.3, p = 0.01), but not with testosterone (p = 0.56 respectively). A negative correlation was found between weight and serum LH (r = - 0.26, p = 0.2) and T/SHBG levels in males (r = - 0.38, p = 0.015 respectively). Weight-SDS was negatively correlated with testosterone in males (r = - 0.25, p = 0.02). Testicular size and breast stage did not correlate with any of the hormonal and anthropometric parameters.  Conclusions: External genitalia in males during mini-puberty is related more to somatic growth rather than reproductive hormones. Similar to pubertal developmental stages, both total and free testosterone are negatively associated with higher weight during mini-puberty. What is Known: • Mini-puberty allows early assessment of HPG axis function in infancy. • There is an inverse relationship between the amount of adipose tissue and circulating testosterone levels in males during puberty and adulthood. • The potential effect of somatic growth and reproductive hormones on external genital development during mini-puberty remains unclear. What is New: • During mini-puberty, males' external genitalia is more related to somatic growth than to reproductive hormones, but this relationship is not observed in girls. • Both total and free testosterone are negatively associated with higher weight during mini-puberty, similar to the pubertal developmental stages.

Characteristic external genitalia in male neonates with 5α-reductase deficiency.

There have been no reports comparing neonatal external genitalia of 5α-reductase deficiency (5αRD) with those of other 46,XY differences of sex differentiation (DSD). This study enrolled 31 Japanese cases of 46,XY DSD whose external genitalia was examined during the neonatal period; four were diagnosed as 5αRD and 15 were defined as non-5αRD by genetic analysis of SRD5A2 or urinary steroid metabolites. We compared the following characteristics between 5αRD and non-5αRD groups, adjusting the severity of undermasculinization of the external genitalia: stretched penile length (SPL), glans width, location of the external urethral opening, and proportion of undescended testis. The external genitalia of all the 5αRD cases were Quigley classification grade 2 or 3. We compared the phenotypes between the four 5αRD cases and 11 non-5αRD cases with grade 2 or 3. The median (range) of SPL in the 5αRD group (14 mm [11-16]) was significantly lower than that in the non-5αRD group (22 mm [15-29]) (p = 0.003). An SPL cut-off value of <15 mm yielded a sensitivity of 50% (95% confidence interval [CI]; 7-93%) and specificity of 100% (95% CI, 72-100%) for discriminating between the groups. The median glans width, location of the external urethral opening, and proportion of undescended testis were not significantly different between the groups. The SPL of 5αRD in Quigley classification grade 2 or 3 was significantly shorter than that of other 46,XY DSDs with the equivalent grade.

Clinical Consensus No. 455: Fetal Sex Determination and Disclosure.

OBJECTIVE: To provide guidance on ultrasound review of the fetal perineum as well as fetal sex determination and disclosure. TARGET POPULATION: All individuals with ongoing pregnancies. OPTIONS: To include a review of the fetal perineum and determination of fetal sex as a component of the anatomic review during the routine second-trimester obstetric ultrasound and adhere to patient wishes regarding the disclosure of fetal sex. OUTCOMES: Prenatal diagnosis of fetal genital and sex anomalies or variants, parental and pregnancy caregiver knowledge of fetal sex, and adherence to parental wishes regarding knowledge of fetal sex. BENEFITS, HARMS, AND COSTS: Benefits include the potential to improve perinatal outcomes through the diagnosis of fetal genital anomalies and respect for women's rightful autonomy over personal health information. Potential harms or costs include a possible error in fetal sex determination, increased time for patients and health care providers in scheduling and performing the imaging, and the minimal risk of patients choosing to abort a pregnancy if the fetus is not the desired sex. EVIDENCE: Evidence built on the literature from the prior version of this statement through a review of international guidelines, Canadian legal rulings, and a literature search of PubMed and the Cochrane Database. English language research articles, review articles, and systematic reviews between January 1, 2003, and December 31, 2023, were included. Search terms included fetal ultrasonography, sex determination, and genitalia. The references of relevant articles were assessed, and applicable articles were included as well. INTENDED AUDIENCE: All care providers for pregnant individuals in Canada. SOCIAL MEDIA ABSTRACT: Fetal genitalia should be examined in pregnancy and the sex safely disclosed to the patient if they want this information.

Sexual fate of murine external genitalia development: Conserved transcriptional competency for male-biased genes in both sexes.

Testicular androgen is a master endocrine factor in the establishment of external genital sex differences. The degree of androgenic exposure during development is well known to determine the fate of external genitalia on a spectrum of female- to male-specific phenotypes. However, the mechanisms of androgenic regulation underlying sex differentiation are poorly defined. Here, we show that the genomic environment for the expression of male-biased genes is conserved to acquire androgen responsiveness in both sexes. Histone H3 at lysine 27 acetylation (H3K27ac) and H3K4 monomethylation (H3K4me1) are enriched at the enhancer of male-biased genes in an androgen-independent manner. Specificity protein 1 (Sp1), acting as a collaborative transcription factor of androgen receptor, regulates H3K27ac enrichment to establish conserved transcriptional competency for male-biased genes in both sexes. Genetic manipulation of MafB, a key regulator of male-specific differentiation, and Sp1 regulatory MafB enhancer elements disrupts male-type urethral differentiation. Altogether, these findings demonstrate conservation of androgen responsiveness in both sexes, providing insights into the regulatory mechanisms underlying sexual fate during external genitalia development.

Evidence of castrations in fleas of small mammals (Chiroptera and Rodentia) from Argentina.

Morphological abnormalities in fleas seem to be common in nature and are under reported in Argentina. In this note, we describe anomalies in two males and one female of Alectopsylla unisetosa Mahnert (Ischnopsyllidae) and one of Polygenis sp. (Rhopalopsyllidae) male collected from small mammals in the provinces of Neuquen and Salta, Argentina. In all specimens, the anomalies were observed at the level of the genitalia recognized as partial castration. The structures mainly affected were the modified abdominal segments, the aedeagus (in male), and the spermatheca (in female). The present communication is the first one devoted exclusively to teratogenous fleas in Argentina.

Clinical Characteristics and Pathogen Spectrum of Male Genital Fungal Infections in Nanchang Area, South China.

The cutaneous fungal infections in male genitalia are relatively rare, and often present with various atypical clinical symptoms. It was mainly reported in a small number of case reports, while data with large number of patients were rarely reported. In this study, we reported 79 male patients with cutaneous fungal infections on scrotum or penis. The fungal infections were confirmed by microscopic examination directly and fungus culture. Clinical characteristics and predisposing factors were also collected. Of these 79 patients, 72 has lesions on scrotum, 5 on penis and 2 on both scrotum and penis. Trichophyton (T.) rubrum is the most common pathogen, found in 50 (67.6%) patients, which presented diverse clinical manifestation such as majorly erythematous, dry diffused scaly lesions without a clear border, slightly powdery and scutular scalings. Candida (C.) albicans is the secondly common pathogen, found in 21 (28.4%) patients, which also presented diverse lesions such as erythematous with dry whitish scaly lesions and erythematous erosion. The predisposing factors mainly included concomitant fungal infections on sites other than genitalia, especially inguinal region (tinea cruris), application of corticosteroid and high moisture. In conclusion, cutaneous fungal infections in male genitalia could be caused by different fungi, showed atypical or mild clinical appearances in most cases and might be a fungus reservoir, emphasizing the necessity to timely perform the fungi examinations and corresponding therapy.

Comparison of Fat Transfer Combined with Plasma Energy and Only Fat Transfer Methods for Genital Rejuvenation.

BACKGROUND: To compare the fat transfer combined with plasma energy and only fat transfer methods for genital rejuvenation and to investigate the efficacy enhancing properties of plasma energy. METHODS: Forty-six patients were equally divided into two groups according to the surgical method as the group A (n = 23) and the group B (n = 23). The patients in the group A received only fat transfer, while the patients in the group B received fat transfer combined with plasma energy. Both groups were scheduled for postoperative follow-up at 1, 3, 6, and 12 months. The lifting effect on the labia majora after the procedure was evaluated with photographs and patient satisfaction questionnaires including the female genital self-image scale (FGSIS). RESULTS: The mean age of all participants was 32.8 ± 5.1 years, and the mean body mass index (BMI) was 24.7 ± 3.4 kg/m2. The mean preoperative FGSIS scores were similar between the groups (p = 0.542). The mean total FGSIS score was 18.8 ± 1.4 in the group A and 18.3 ± 1.5 in the group B in the preoperative period. However, the mean FGSIS scores at 1, 3, and 6 months were significantly higher in the group B than the group A (p = 0.032, p = 0.012, and p = 0.009, respectively). At 6 months of follow-up, the mean total FGSIS score was 20.7 ± 1.4 in the group A and 22.3 ± 1.5 in the group B, indicating a statistically significant difference (p = 0.028). CONCLUSION: This novel technique is a more minimally invasive technique compared to other energy modalities with lower lateral and vertical energy dissipation than other conventional methods, and labia majora fat filling augmentation application can be performed with more permanent and longer-lasting outcomes than fat transfer only. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The Role of Suprapubic Superficial Fascial System Reconstruction During Repair of Adult-Acquired Buried Penis.

BACKGROUND: Adult-Acquired Buried Penis is a disorder associated with systemic obesity that confers increased risks of malignancy, sexual dysfunction, urinary abnormalities, and psychological distress. Surgical correction improves patient-reported functional and psychological outcomes and often requires collaboration between plastic and urologic surgeons. To improve postoperative cosmetic outcomes and decrease wound complications following adult-acquired buried penis repair, we performed an anatomic and histologic study of the superficial fascial layers providing support to the external male genitalia and describe our approach for fascial reconstruction. METHODS: We characterized the superficial fascial anatomy in three patients undergoing adult-acquired buried penis repair, including two patients with Wisconsin Type II disease and one patient with Wisconsin Type IV disease. Gross specimens were sent from two patients histologic analysis using H&E and elastin-specific stains to characterize the identity of the superficial fibrofatty tissue. RESULTS: In all three patients, the fundiform ligament overlying the suspensory ligament was identified, isolated, and transected for removal with the suprapubic specimen. We found that reapproximation of this ligament following transection at the time of escutcheonectomy provided significant lift to the penis and genitals via improved support of dartos fascia. Histologic analysis of the superficial fibrofatty tissue located beneath the dermis revealed histologic similarities with the superficial fascial system described previously in abdominal and breast tissue. CONCLUSIONS: Reapproximation of the fundiform ligament and superficial fascial tissue following suprapubic/lower abdominal fat pad removal during adult-acquired buried penis may improve postoperative cosmesis by reducing strain on the dermal closure. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Moment of induction and duration of experimental varicocele in rats: effects on semen quality.

PURPOSE: Varicocele is a condition known to cause damage to seminal parameters and sperm function. Furthermore, it has been hypothesized that the varicocele effect on fertility is time-dependent; however, little is known about the consequences of its establishment time on reproductive organs and/or sperm function. This study aimed to evaluate the effect of the duration of experimental varicocele on reproductive organs, sperm parameters, and sperm function. MATERIALS AND METHODS: Varicocele induction surgeries were performed in Wistar rats aged 40 or 100 days old. At 160-day-old, analyses were performed, including biometry of reproductive organs (prostate, seminal vesicles, epididymis, and testis), sperm parameters (vitality, morphology, and motility), and sperm function tests (nuclear DNA integrity, acrosome integrity, and mitochondrial activity). RESULTS: The analysis of the biometry of reproductive organs showed no differences between distinct ages in which varicocele was induced. The total abnormal sperm morphology was bigger in animals with varicocele induced to 100 days old than in animals with varicocele induced to 40 days old. Regarding nuclear DNA integrity, animals of varicocele induced to 100 days old showed worse results compared to animals of varicocele induced to 40 days old. Other parameters analyzed showed no differences between varicocele groups. CONCLUSION: In this study conducted on rats, we conclude that varicocele adversely affects sperm, particularly its function. However, we did not observe a negative progressive effect on sperm.

Developmental and functional roles of androgen and interactive signals for external genitalia and erectile tissues.

Background: Recent progress in molecular and signal analyses revealed essential functions of cellular signals including androgen and related growth factors such as Wnt regulators for external genitalia (ExG) development and its pathogenesis. Accumulated data showed their fundamental functions also for erectile tissue (corporal body) development and its abnormalities. The current review focuses on such signals from developmental and functional viewpoints. Methods: Experimental strategies including histological and molecular signal analyses with conditional mutant mice for androgen and Wnt signals have been extensively utilized. Main findings: Essential roles of androgen for the development of male-type ExG and urethral formation are shown. Wnt signals are associated with androgen for male-type ExG organogenesis. Androgen plays essential roles in the development of erectile tissue, the corporal body and it also regulates the duration time of erection. Wnt and other signals are essential for the regulation of mesenchymal cells of erectile tissue as shown by its conditional mutant mouse analyses. Stress signals, continuous erection, and the potential of lymphatic characteristics of the erectile vessels with sinusoids are also shown. Conclusion: Reiterated involvement of androgen, Wnt, and other regulatory factors is stated for the development and pathogenesis of ExG and erectile tissues.

Expression of posterior Hox genes and opisthosomal appendage development in a mygalomorph spider.

Spiders represent an evolutionary successful group of chelicerate arthropods. The body of spiders is subdivided into two regions (tagmata). The anterior tagma, the prosoma, bears the head appendages and four pairs of walking legs. The segments of the posterior tagma, the opisthosoma, either lost their appendages during the course of evolution or their appendages were substantially modified to fulfill new tasks such as reproduction, gas exchange, and silk production. Previous work has shown that the homeotic Hox genes are involved in shaping the posterior appendages of spiders. In this paper, we investigate the expression of the posterior Hox genes in a tarantula that possesses some key differences of posterior appendages compared to true spiders, such as the lack of the anterior pair of spinnerets and a second set of book lungs instead of trachea. Based on the observed differences in posterior Hox gene expression in true spiders and tarantulas, we argue that subtle changes in the Hox gene expression of the Hox genes abdA and AbdB are possibly responsible for at least some of the morphological differences seen in true spiders versus tarantulas.

Developmental regulation of the male urogenital papilla in the male marine teleost black rockfish, Sebastes schlegelii (Hilgendorf, 1880)†.

The male external genitalia of the black rockfish (Sebastes schlegelii Hilgendorf, 1880) is a fleshy protrusion known as the urogenital papilla (UGP), which functions to deliver sperm into the female reproductive tract for internal fertilization. It is not known which genes regulate the development of the UGP. The aim of this study was to identify key genes that regulate the development of the UGP in black rockfish and to determine the distribution of androgen receptor gene (ar) in the UGP. A total of 26 adult males and 560 juvenile fish were used in the experiment, in which we divided all normally developing juveniles into normal development and androgen groups. We added methyltestosterone solution (100 µg/l) to the androgen group-treated fish tank, soaked for 2 h per day for 38 days, and sampled 5~10 samples each time every 5 days during the culture process. Gene expression changes related to UGP were analyzed with tissue specificity between control and androgen groups during sex differentiation, adult male maturation, and the copulation stage (September to December) using real-time quantitative polymerase chain reaction. The expression of ar was also localized by two-color in situ hybridization in the UGP region of juvenile fish. Androgen treatment enhanced ar expression levels and the ar signal was stronger in the UGP region of both adult breeding fish and androgen-treated juvenile fish. This study provides insights into the regulation of the external genitalia of black rockfish and presents vital information for the artificial breeding of viviparous fish.

Resolving between novelty and homology in the rapidly evolving phallus of Drosophila.

The genitalia present some of the most rapidly evolving anatomical structures in the animal kingdom, possessing a variety of parts that can distinguish recently diverged species. In the Drosophila melanogaster group, the phallus is adorned with several processes, pointed outgrowths, that are similar in size and shape between species. However, the complex three-dimensional nature of the phallus can obscure the exact connection points of each process. Previous descriptions based upon adult morphology have primarily assigned phallic processes by their approximate positions in the phallus and have remained largely agnostic regarding their homology relationships. In the absence of clearly identified homology, it can be challenging to model when each structure first evolved. Here, we employ a comparative developmental analysis of these processes in eight members of the melanogaster species group to precisely identify the tissue from which each process forms. Our results indicate that adult phallic processes arise from three pupal primordia in all species. We found that in some cases the same primordia generate homologous structures whereas in other cases, different primordia produce phenotypically similar but remarkably non-homologous structures. This suggests that the same gene regulatory network may have been redeployed to different primordia to induce phenotypically similar traits. Our results highlight how traits diversify and can be redeployed, even at short evolutionary scales.