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Armfield BA, Cohn MJ. Single cell transcriptomic analysis of external genitalia reveals complex and sexually dimorphic cell populations in the early genital tubercle. Dev Biol 2021; 477:145-154. [PMID: 34033822 DOI: 10.1016/j.ydbio.2021.05.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 11/27/2022]
Abstract
External genital organs are among the most recognizable sexually dimorphic characters. The penis and clitoris develop from the embryonic genital tubercle, an outgrowth at the anterior margin of the cloaca that undergoes an extensive period of development in male and female embryos prior to the onset of sexual differentiation. In mice, differentiation into the penis and clitoris begins around embryonic day (E)15.5. Current knowledge of cell types that comprise the genital tubercle is limited to a few studies that have fate mapped derivatives of endoderm, mesoderm, and ectoderm. Here we use single cell transcriptomics to characterize the cell populations in the genital tubercles of male and female mouse embryos at E14.5, approximately 24 h before the onset of sexual differentiation, and we present the first comprehensive atlas of single-cell gene expression during external genital development. Clustering analyses and annotation using marker genes shows 19 distinct cell populations in E14.5 genital tubercles. Mapping of cell clusters to anatomical locations using in situ gene expression patterns revealed granularity of cellular specializations and positional identities. Although E14.5 precedes sexually dimorphic morphogenesis of the genital tubercle, comparative analysis of males and females identified sexual dimorphisms at the single cell level, including male-specific cell clusters with transcriptional signatures of smooth muscle and bone progenitors, both of which are known to be sexually dimorphic in adult genitalia, as well as immune cells. These results provide a new resource for classification of external genital cell types based on gene expression profiles and reveal sex-specific cellular specializations in the early genital tubercle.
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Affiliation(s)
- Brooke A Armfield
- Department of Molecular Genetics and Microbiology, UF Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.
| | - Martin J Cohn
- Department of Molecular Genetics and Microbiology, UF Genetics Institute, University of Florida, Gainesville, FL, 32610, USA; Department of Biology, University of Florida, Gainesville, FL, 32611, USA.
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Fenelon JC, McElrea C, Shaw G, Evans AR, Pyne M, Johnston SD, Renfree MB. The Unique Penile Morphology of the Short-Beaked Echidna, Tachyglossus aculeatus. Sex Dev 2021; 15:262-271. [PMID: 33915542 DOI: 10.1159/000515145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/08/2021] [Indexed: 11/19/2022] Open
Abstract
Monotremes diverged from therian mammal ancestors approximately 184 million years ago and have a number of novel reproductive characteristics. One in particular is their penile morphology. There are differences between echidna and platypus phalluses, but both are somewhat similar in structure to the reptilian phallus. The echidna penis consists of 4 rosette glans, each of which contains a termination of the quadrifurcate urethra, but it appears that only 2 of the 4 glans become erect at any one time. Despite this, only a few historical references describe the structure of the echidna penis and none provides an explanation for the mechanisms of unilateral ejaculation. This study confirmed that the echidna penis contains many of the same overall structures and morphology as other mammalian penises and a number of features homologous with reptiles. The corpus cavernosum is well supplied with blood, extends up to the base of the glans penis and is primarily responsible for erection. However, the echidna possesses 2 distinct corpora spongiosa separated by a septum, each of which surround the urethra only distal to the initial urethral bifurcation in the glans penis. Together with the bifurcation of the main penile artery, this provides a mechanism by which blood flow could be directed to only one corpus spongiosum at a time to maintain an open urethra that supplies 2 of the 4 glans to facilitate unilateral ejaculation.
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Affiliation(s)
- Jane C Fenelon
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Caleb McElrea
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Geoff Shaw
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Michael Pyne
- Currumbin Wildlife Sanctuary, Currumbin, Queensland, Australia
| | - Stephen D Johnston
- School of Agriculture and Food Science, University of Queensland, Gatton, Queensland, Australia
| | - Marilyn B Renfree
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
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Gonçalves GL, Medina DS, Bohorquez Grondona KE, Quagliatto Santos AL, Bohórquez Mahecha GA. Topographic Relationships of the Peritoneal Canal of Testudines, Crocodylia, and Aves: Evolutionary Implications. SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2021. [DOI: 10.2994/sajh-d-18-00061.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Gustavo Leite Gonçalves
- Pós-Graduação em Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil
| | - Douglas Sales Medina
- Departamento de Biologia Geral, Laboratório de Biotecnologia e Marcadores Moleculares, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil
| | - Katerin Elena Bohorquez Grondona
- Departamento de Medicina Veterinária, Universidade Federal de Juiz de Fora, Rua José Lourenço Kelmer, s/n, São Pedro, Juiz de Fora, MG, Brazil
| | - André Luiz Quagliatto Santos
- Hospital veterinário, Faculdade de Medicina Veterinária, Universidade Federal de Uberlândia, Av. João Naves de Ávila 2121, Campus Santa Mônica, Uberlândia, Brazil
| | - Germán Arturo Bohórquez Mahecha
- Pós-Graduação em Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil
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Blackburn DG. Functional morphology, diversity, and evolution of yolk processing specializations in embryonic reptiles and birds. J Morphol 2020; 282:995-1014. [PMID: 32960458 DOI: 10.1002/jmor.21267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/24/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022]
Abstract
Evolution of the terrestrial, amniotic egg of vertebrates required new mechanisms by which yolk material could be processed for embryonic use. Recent studies on each of the major extant reptile groups have revealed elaborate morphological specializations for yolk processing, features that differ dramatically from those of birds. In the avian pattern, liquid yolk is housed in a yolk sac whose endodermal lining absorbs and digests yolk material and sends resultant nutrients into the blood circulation. In snakes, lizards, turtles, and crocodilians, as documented herein, the yolk sac becomes invaded by endodermal cells that proliferate and phagocytose yolk material. Blood vessels then invade, and the endodermal cells become arranged around them, forming elongated "spaghetti-like" strands that fill the yolk sac cavity. This pattern provides an effective means by which yolk material is cellularized, digested, and transported by vitelline vessels to the developing embryo. Phylogenetically, the (non-avian) "reptilian" pattern was ancestral for sauropsids and was modified or replaced in ancestors to birds. This review postulates that evolution of the "avian" pattern involved increased reliance on extracellular digestion of yolk, allowing embryonic development to occur more rapidly than in typical reptiles. Comparative studies of yolk processing that draw on morphological, biochemical, molecular approaches are needed to explain how and why the "reptilian" pattern was replaced in birds or their archosaurian ancestors.
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Affiliation(s)
- Daniel G Blackburn
- Department of Biology, Electron Microscopy Center, Trinity College, Hartford, Connecticut, USA
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Moore BC, Francis R, Foster A, Kelly DA, Does M, Kim DK, Groenewald HB, Myburgh JG. Morphological changes associated with Nile crocodile (Crocodylus niloticus) phallic glans inflation. J Morphol 2020; 281:636-645. [PMID: 32271493 DOI: 10.1002/jmor.21126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 12/23/2022]
Abstract
The crocodylian phallic glans is the distal inflatable structure that makes the most direct contact with the female cloacal and associated reproductive tract openings during copulation. Therefore, its form and function directly impact female tissue sensory interactions and insemination mechanics. Compared to mammals, less is known about glans functional anatomy among other amniotes, including crocodylians. Therefore, we paired an ex vivo inflation technique with magnetic resonance imaging 3D-reconstructions and corresponding histological analyses to better characterize the morphological glans restructuring occurring in the Nile crocodile (Crocodylus niloticus) at copulation. The expansion of contiguous inflatable spongiform glans tissues is variably constrained by adjacent regions of dense irregular collagen-rich tissues. Therefore, expansion shows regional differences with greater lateral inflation than dorsal and ventral. Furthermore, this enlargement elaborates the cup-like glans lumen, dorsally reorients the glans ridge, stiffens the blunt and bifid glans tip, and putatively works to seal the ventral sulcus spermaticus semen conduit groove. We suggest how these dynamic male structures may interact with structures of the female cloacal urodeum and how these morphological changes, in concert with the varying material properties of the structural tissue compartments visualized in this study, aid copulatory gamete transfer and resulting fecundity. RESEARCH HIGHLIGHTS: Nile crocodile glans inflation produces a reproductively relevant copulatory structure directing insemination and female tissue interactions. Pairing magnetic resonance imaging 3D reconstruction with corresponding histology effectively studies functional anatomy.
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Affiliation(s)
- Brandon C Moore
- College of Veterinary Medicine, Department of Biomedical Science, University of Missouri, Columbia, Missouri, USA.,Biology Department, Sewanee: The University of the South, Sewanee, Tennessee, USA
| | - Rachel Francis
- Biology Department, Sewanee: The University of the South, Sewanee, Tennessee, USA
| | - Adam Foster
- Biology Department, Sewanee: The University of the South, Sewanee, Tennessee, USA
| | - Diane A Kelly
- Psychological and Brain Sciences, University of Massachusetts, Amherst, Massachusetts, USA
| | - Mark Does
- Department of Biomedical Engineering, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Dong K Kim
- Department of Biomedical Engineering, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Herman B Groenewald
- Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Jan G Myburgh
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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Wang S, Zheng Z. Differential cell proliferation and cell death during the urethral groove formation in guinea pig model. Pediatr Res 2019; 86:452-459. [PMID: 30467344 DOI: 10.1038/s41390-018-0236-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 10/28/2018] [Indexed: 11/09/2022]
Abstract
BACKGROUND Urethral groove (UG) formation is an important step in penile formation. Because commonly used animal models do not have UG, the mechanisms of UG formation have never been discovered. We aim to discover the cellular mechanism of the UG formation using guinea pig model. METHODS Histology was used to study the ontogeny of UG. BrdU immunofluorescence was used to label proliferating cells, cell death was determined using LysoTracker Red and TUNEL staining, and stereology was used for quantification. To reveal Shh mRNA expression patterns, in situ hybridization was performed in guinea pig genital tubercles (GTs) and ShhGFPcre-LacZ-reporter mice were used for comparison. RESULTS Cell proliferation in the outer layers and programmed cell death in the inner layers of urethral epithelium played key roles during urethral canal movement from dorsal to ventral aspect and final opening to form UG. Shh mRNA expression domain shifted out to the ventral surface of GT from proximal throughout to distal in guinea pigs, but was excluded from the ventral surface epithelium in midshaft and distal of mouse GT. CONCLUSION Differential cell proliferation and cell death in developing urethral epithelium lead to UG formation and Shh expression in ventral surface epithelium of GT may play an important role.
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Affiliation(s)
- Shanshan Wang
- Department of Physiology, School of Medicine, Southern Illinois University Carbondale, Carbondale, IL, 62901, USA
| | - Zhengui Zheng
- Department of Physiology, School of Medicine, Southern Illinois University Carbondale, Carbondale, IL, 62901, USA.
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Chen Y, Yu H, Pask AJ, Fujiyama A, Suzuki Y, Sugano S, Shaw G, Renfree MB. Hormone-responsive genes in the SHH and WNT/β-catenin signaling pathways influence urethral closure and phallus growth. Biol Reprod 2019; 99:806-816. [PMID: 29767687 DOI: 10.1093/biolre/ioy117] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 05/13/2018] [Indexed: 11/14/2022] Open
Abstract
Environmental endocrine disruptors (EEDs) that affect androgen or estrogen activity may disrupt gene regulation during phallus development to cause hypospadias or a masculinized clitoris. We treated developing male tammar wallabies with estrogen and females with androgen from day 20-40 postpartum (pp) during the androgen imprinting window of sensitivity. Estrogen inhibited phallus elongation but had no effect on urethral closure and did not significantly depress testicular androgen synthesis. Androgen treatment in females did not promote phallus elongation but initiated urethral closure. Phalluses were collected for transcriptome sequencing at day 50 pp when they first become sexually dimorphic to examine changes in two signaling pathways, sonic hedgehog (SHH) and wingless-type MMTV integration site family (WNT)/β-catenin. SHH mRNA and β-catenin were predominantly expressed in the urethral epithelium in the tammar phallus, as in eutherian mammals. Estrogen treatment and castration of males induced an upregulation of SHH, while androgen treatment downregulated SHH. These effects appear to be direct since we detected putative estrogen receptor α (ERα) and androgen receptor (AR) binding sites near SHH. WNT5A, like SHH, was downregulated by androgen, while WNT4 was upregulated in female phalluses after androgen treatment. After estrogen treatment, WIF1 and WNT7A were both downregulated in male phalluses. After castration, WNT9A was upregulated. These results suggest that SHH and WNT pathways are regulated by both estrogen and androgen to direct the proliferation and elongation of the phallus during differentiation. Their response to exogenous hormones makes these genes potential targets of EEDs in the etiology of abnormal phallus development including hypospadias.
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Affiliation(s)
- Yu Chen
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Hongshi Yu
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Andrew J Pask
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Asao Fujiyama
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Sumio Sugano
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Geoff Shaw
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Victoria, Australia
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Ultrastructural analysis of the yolk processing pattern in embryonic pond slider turtles (Trachemys scripta: Emydidae). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 332:187-197. [DOI: 10.1002/jez.b.22894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/19/2019] [Accepted: 06/27/2019] [Indexed: 01/19/2023]
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Gradela A, Pires IC, Faria MD, Matos MHT, Costa MM, Souza RKC, Milanelo L, Franzo VS. Morphology and biometry of the reproductive organs of adult males of Trachemys scripta elegans reared in São Paulo state, Brazil. PESQUISA VETERINARIA BRASILEIRA 2019. [DOI: 10.1590/1678-5150-pvb-5848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT: Trachemys scripta elegans is an American underwater chelonian illegally marketed in Brazilian pet shops. When abandoned in nature, it compromises native species, threatening local biodiversity. However, little is known about the body development and structure of its reproductive tract. The objective of the present study was to investigate the morphology and biometry of testis, epididymis and penis, as well as the biometry of the body and secondary sexual characters in this species. Twenty-seven adult males were used aiming to contribute to preservation actions in captivity, population control, and scientific research, as well as to interspecific comparisons. Sex identification by the third claw length was effective, and the specimens presented harmonious and positive body development between mass, carapace, plastron, and height, with unimodal tendency and higher frequency of maximum carapace length at 15cm. The testes and epididymides presented biometric similarity between the antimeres and anatomical and histological structure similar to that of other species of chelonians and mammals, except for the type of epithelium. The findings suggest that there is conserved morphology between slider turtles and homology in relation to mammals. Histological similarity to the reproductive organs of other amniotes, including humans, may give rise to scientific and comparative studies, essential for the establishment of conservation strategies in reptiles.
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Sanger TJ, Kircher BK. Model Clades Versus Model Species: Anolis Lizards as an Integrative Model of Anatomical Evolution. Methods Mol Biol 2017; 1650:285-297. [PMID: 28809029 DOI: 10.1007/978-1-4939-7216-6_19] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Anolis lizards , known for their replicated patterns of morphological diversification, are widely studied in the fields of evolution and ecology. As a textbook example of adaptive radiation, this genus has supported decades of intense study in natural history, behavior, morphological evolution, and systematics. Following the publication of the A. carolinensis genome, research on Anolis lizards has expanded into new areas, toward obtaining an understanding the developmental and genetic bases of anole diversity. Here, we discuss recent progress in these areas and the burgeoning methodological toolkit that has been used to elucidate the genetic mechanisms underlying anatomical variation in this group. We also highlight the growing number of studies that have used A. carolinensis as the representative squamate in large-scale comparison of amniote evolution and development . Finally, we address one of the largest technical challenges biologists are facing in making Anolis a model for integrative studies of ecology, evolution, development , and genetics, the development of ex-ovo culturing techniques that have broad utility. Ultimately, with the power to ask questions across all biological scales in this diverse genus full, anoles are rapidly becoming a uniquely integrative and powerful biological system.
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Affiliation(s)
- Thomas J Sanger
- Department of Biology, Loyola University Chicago, Chicago, IL, 60660, USA.
| | - Bonnie K Kircher
- Department of Biology, University of Florida, Gainesville, FL, 32601, USA
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Gredler ML. Developmental and Evolutionary Origins of the Amniote Phallus. Integr Comp Biol 2016; 56:694-704. [DOI: 10.1093/icb/icw102] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Sanger TJ, Gredler ML, Cohn MJ. Resurrecting embryos of the tuatara, Sphenodon punctatus, to resolve vertebrate phallus evolution. Biol Lett 2015; 11:20150694. [PMID: 26510679 PMCID: PMC4650183 DOI: 10.1098/rsbl.2015.0694] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 09/30/2015] [Indexed: 11/12/2022] Open
Abstract
The breadth of anatomical and functional diversity among amniote external genitalia has led to uncertainty about the evolutionary origins of the phallus. In several lineages, including the tuatara, Sphenodon punctatus, adults lack an intromittent phallus, raising the possibility that the amniote ancestor lacked external genitalia and reproduced using cloacal apposition. Accordingly, a phallus may have evolved multiple times in amniotes. However, similarities in development across amniote external genitalia suggest that the phallus may have a single evolutionary origin. To resolve the evolutionary history of amniote genitalia, we performed three-dimensional reconstruction of Victorian era tuatara embryos to look for embryological evidence of external genital initiation. Despite the absence of an intromittent phallus in adult tuataras, our observations show that tuatara embryos develop genital anlagen. This illustrates that there is a conserved developmental stage of external genital development among all amniotes and suggests a single evolutionary origin of amniote external genitalia.
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Affiliation(s)
- Thomas J Sanger
- Department of Molecular Genetics and Microbiology, University of Florida, PO Box 103610, Gainesville, FL 32610, USA
| | - Marissa L Gredler
- Department of Biology, University of Florida, PO Box 103610, Gainesville, FL 32610, USA
| | - Martin J Cohn
- Department of Molecular Genetics and Microbiology, University of Florida, PO Box 103610, Gainesville, FL 32610, USA Department of Biology, University of Florida, PO Box 103610, Gainesville, FL 32610, USA Howard Hughes Medical Institute, University of Florida, PO Box 103610, Gainesville, FL 32610, USA
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Tschopp P, Sherratt E, Sanger TJ, Groner AC, Aspiras AC, Hu JK, Pourquié O, Gros J, Tabin CJ. A relative shift in cloacal location repositions external genitalia in amniote evolution. Nature 2014; 516:391-4. [PMID: 25383527 PMCID: PMC4294627 DOI: 10.1038/nature13819] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/20/2014] [Indexed: 12/23/2022]
Abstract
The move of vertebrates to a terrestrial lifestyle required major adaptations in their locomotory apparatus and reproductive organs. While the fin-to-limb transition has received considerable attention, little is known about the developmental and evolutionary origins of external genitalia. Similarities in gene expression have been interpreted as a potential evolutionary link between the limb and genitals; however, no underlying developmental mechanism has been identified. We re-examined this question using micro-computed tomography, lineage tracing in three amniote clades, and RNA-sequencing-based transcriptional profiling. Here we show that the developmental origin of external genitalia has shifted through evolution, and in some taxa limbs and genitals share a common primordium. In squamates, the genitalia develop directly from the budding hindlimbs, or the remnants thereof, whereas in mice the genital tubercle originates from the ventral and tail bud mesenchyme. The recruitment of different cell populations for genital outgrowth follows a change in the relative position of the cloaca, the genitalia organizing centre. Ectopic grafting of the cloaca demonstrates the conserved ability of different mesenchymal cells to respond to these genitalia-inducing signals. Our results support a limb-like developmental origin of external genitalia as the ancestral condition. Moreover, they suggest that a change in the relative position of the cloacal signalling centre during evolution has led to an altered developmental route for external genitalia in mammals, while preserving parts of the ancestral limb molecular circuitry owing to a common evolutionary origin.
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Affiliation(s)
- Patrick Tschopp
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Emma Sherratt
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
| | - Thomas J. Sanger
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
| | - Anna C. Groner
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Ariel C. Aspiras
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Jimmy K. Hu
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Olivier Pourquié
- Department of Genetics, Harvard Medical School, Boston, MA 02115
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA 02115
| | - Jérôme Gros
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75724 Paris Cedex 15, France
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Herrera AM, Cohn MJ. Embryonic origin and compartmental organization of the external genitalia. Sci Rep 2014; 4:6896. [PMID: 25372631 PMCID: PMC4894444 DOI: 10.1038/srep06896] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 10/15/2014] [Indexed: 11/09/2022] Open
Abstract
Genital malformations occur at a high frequency in humans, affecting ~1:250 live births. The molecular mechanisms of external genital development are beginning to be identified; however, the origin of cells that give rise to external genitalia is unknown. Here we use cell lineage analysis to show that the genital tubercle, the precursor of the penis and clitoris, arises from two populations of progenitor cells that originate at the lateral edges of the embryo, at the level of the posterior hindlimb buds and anterior tail. During body wall closure, the left and right external genital progenitor pools are brought together at the ventral midline, where they form the paired genital swellings that give rise to the genital tubercle. Unexpectedly, the left and right external genital progenitor pools form two lineage-restricted compartments in the phallus. Together with previous lineage studies of limb buds, our results indicate that, at the pelvic level, the early lateral mesoderm is regionalized from medial to lateral into dorsal limb, ventral limb, and external genital progenitor fields. These findings have implications for the evolutionary diversification of external genitalia and for the association between external genital defects and disruption of body wall closure, as seen in the epispadias-extrophy complex.
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Affiliation(s)
- Ana M Herrera
- Department of Molecular Genetics and Microbiology, Howard Hughes Medical Institute, UF Genetics Institute, University of Florida, P.O. Box 103610, Gainesville, FL 32610, USA
| | - Martin J Cohn
- 1] Department of Molecular Genetics and Microbiology, Howard Hughes Medical Institute, UF Genetics Institute, University of Florida, P.O. Box 103610, Gainesville, FL 32610, USA [2] Department of Biology, Howard Hughes Medical Institute, UF Genetics Institute, University of Florida, P.O. Box 103610, Gainesville, FL 32610, USA
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Gredler ML, Larkins CE, Leal F, Lewis AK, Herrera AM, Perriton CL, Sanger TJ, Cohn MJ. Evolution of External Genitalia: Insights from Reptilian Development. Sex Dev 2014; 8:311-26. [DOI: 10.1159/000365771] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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