1
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The Connection between Immunocompetence and Reproduction in Wildlife. Life (Basel) 2023; 13:life13030785. [PMID: 36983939 PMCID: PMC10051471 DOI: 10.3390/life13030785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/07/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023] Open
Abstract
Reproduction rate is important for the survival of animal populations. During gravidity, a trade-off occurs between the individual well-being of gravid females and investment in offspring. Due to the high synthesis and energy requirements for the growing fetus, other physiological activities are downregulated in pregnant females. This causes changes in the composition of the reproductive microbiome and a decreased immune response to presented antigens and pathogens. As a result, the immunocompetence of gravid wild animals declines. In general, therefore, increased infection rates during pregnancy can be observed in all wildlife species studied. In the course of evolution, however, this has apparently evolved as a suitable strategy to ensure the survival of the population as a whole.
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2
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Whittington CM, Buddle AL, Griffith OW, Carter AM. Embryonic specializations for vertebrate placentation. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210261. [PMID: 36252220 PMCID: PMC9574634 DOI: 10.1098/rstb.2021.0261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 02/28/2022] [Indexed: 12/20/2022] Open
Abstract
The vertebrate placenta, a close association of fetal and parental tissue for physiological exchange, has evolved independently in sharks, teleost fishes, coelacanths, amphibians, squamate reptiles and mammals. This transient organ forms during pregnancy and is an important contributor to embryonic development in both viviparous and oviparous, brooding species. Placentae may be involved in transport of respiratory gases, wastes, immune molecules, hormones and nutrients. Depending on the taxon, the embryonic portion of the placenta is comprised of either extraembryonic membranes (yolk sac or chorioallantois) or temporary embryonic tissues derived via hypertrophy of pericardium, gill epithelium, gut, tails or fins. These membranes and tissues have been recruited convergently into placentae in several lineages. Here, we highlight the diversity and common features of embryonic tissues involved in vertebrate placentation and suggest future studies that will provide new knowledge about the evolution of pregnancy. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'.
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Affiliation(s)
- Camilla M. Whittington
- School of Life and Environmental Sciences, The University of Sydney, Heydon-Laurence A08, New South Wales 2006, Australia
| | - Alice L. Buddle
- School of Life and Environmental Sciences, The University of Sydney, Heydon-Laurence A08, New South Wales 2006, Australia
| | - Oliver W. Griffith
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Anthony M. Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, J. B. Winsloews Vej 21, 5000 Odense, Denmark
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3
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Major AT, Estermann MA, Roly ZY, Smith CA. An evo-devo perspective of the female reproductive tract. Biol Reprod 2021; 106:9-23. [PMID: 34494091 DOI: 10.1093/biolre/ioab166] [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: 07/11/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 01/22/2023] Open
Abstract
The vertebrate female reproductive tract has undergone considerable diversification over evolution, having become physiologically adapted to different reproductive strategies. This review considers the female reproductive tract from the perspective of evolutionary developmental biology (evo-devo). Very little is known about how the evolution of this organ system has been driven at the molecular level. In most vertebrates, the female reproductive tract develops from paired embryonic tubes, the Müllerian ducts. We propose that formation of the Müllerian duct is a conserved process that has involved co-option of genes and molecular pathways involved in tubulogenesis in the adjacent mesonephric kidney and Wolffian duct. Downstream of this conservation, genetic regulatory divergence has occurred, generating diversity in duct structure. Plasticity of the Hox gene code and wnt signaling, in particular, may underlie morphological variation of the uterus in mammals, and evolution of the vagina. This developmental plasticity in Hox and Wnt activity may also apply to other vertebrates, generating the morphological diversity of female reproductive tracts evident today.
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Affiliation(s)
- Andrew T Major
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, 3800. Australia
| | - Martin A Estermann
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, 3800. Australia
| | - Zahida Y Roly
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, 3800. Australia
| | - Craig A Smith
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, 3800. Australia
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4
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Exaptation of Retroviral Syncytin for Development of Syncytialized Placenta, Its Limited Homology to the SARS-CoV-2 Spike Protein and Arguments against Disturbing Narrative in the Context of COVID-19 Vaccination. BIOLOGY 2021; 10:biology10030238. [PMID: 33808658 PMCID: PMC8003504 DOI: 10.3390/biology10030238] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 12/21/2022]
Abstract
Simple Summary The anti-vaccination movement claims an alleged danger of the COVID-19 vaccine based on the presupposed similarity between syncytin, which plays a role in human placentation and the SARS-CoV-2 spike protein. We argue that because of very low sequence similarity between human syncytin-1 and the SARS-CoV-2 S protein, it is unlikely that any S protein-specific SARS-CoV-2 vaccine would generate an immune response which would affect fertility and pregnancy. However, further evaluation of potential impacts of COVID-19 vaccines on fertility, placentation, pregnancy and general health of mother and newborn is required. Abstract Human placenta formation relies on the interaction between fused trophoblast cells of the embryo with uterine endometrium. The fusion between trophoblast cells, first into cytotrophoblast and then into syncytiotrophoblast, is facilitated by the fusogenic protein syncytin. Syncytin derives from an envelope glycoprotein (ENV) of retroviral origin. In exogenous retroviruses, the envelope glycoproteins coded by env genes allow fusion of the viral envelope with the host cell membrane and entry of the virus into a host cell. During mammalian evolution, the env genes have been repeatedly, and independently, captured by various mammalian species to facilitate the formation of the placenta. Such a shift in the function of a gene, or a trait, for a different purpose during evolution is called an exaptation (co-option). We discuss the structure and origin of the placenta, the fusogenic and non-fusogenic functions of syncytin, and the mechanism of cell fusion. We also comment on an alleged danger of the COVID-19 vaccine based on the presupposed similarity between syncytin and the SARS-CoV-2 spike protein.
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5
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Hernández-Díaz N, Leal F, Ramírez-Pinilla MP. Parallel evolution of placental calcium transfer in the lizard Mabuya and eutherian mammals. J Exp Biol 2021; 224:jeb.237891. [PMID: 33568441 DOI: 10.1242/jeb.237891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/01/2021] [Indexed: 12/28/2022]
Abstract
An exceptional case of parallel evolution between lizards and eutherian mammals occurs in the evolution of viviparity. In the lizard genus Mabuya, viviparity provided the environment for the evolution of yolk-reduced eggs and obligate placentotrophy. One major event that favored the evolution of placentation was the reduction of the eggshell. As with all oviparous reptiles, lizard embryos obtain calcium from both the eggshell and egg yolk. Therefore, the loss of the eggshell likely imposes a constraint for the conservation of the egg yolk, which can only be obviated by the evolution of alternative mechanisms for the transport of calcium directly from the mother. The molecular and cellular mechanisms employed to solve these constraints, in a lizard with only a rudimentary eggshell such as Mabuya, are poorly understood. Here, we used RT-qPCR on placental and uterine samples during different stages of gestation in Mabuya, and demonstrate that transcripts of the calcium transporters trpv6, cabp28k, cabp9k and pmca are expressed and gradually increase in abundance through pregnancy stages, reaching their maximum expression when bone mineralization occurs. Furthermore, CABP28K/9K proteins were studied by immunofluorescence, demonstrating expression in specific regions of the mature placenta. Our results indicate that the machinery for calcium transportation in the Mabuya placenta was co-opted from other tissues elsewhere in the vertebrate bodyplan. Thus, the calcium transportation machinery in the placenta of Mabuya evolved in parallel with the mammalian placenta by redeploying the expression of similar calcium transporter genes.
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Affiliation(s)
- Nathaly Hernández-Díaz
- Grupo de Estudios en Biodiversidad, Escuela de Biología, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
| | - Francisca Leal
- Grupo de Estudios en Biodiversidad, Escuela de Biología, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
| | - Martha Patricia Ramírez-Pinilla
- Grupo de Estudios en Biodiversidad, Escuela de Biología, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia
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6
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Blackburn DG, Stewart JR. Morphological research on amniote eggs and embryos: An introduction and historical retrospective. J Morphol 2021; 282:1024-1046. [PMID: 33393149 DOI: 10.1002/jmor.21320] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 12/21/2022]
Abstract
Evolution of the terrestrial egg of amniotes (reptiles, birds, and mammals) is often considered to be one of the most significant events in vertebrate history. Presence of an eggshell, fetal membranes, and a sizeable yolk allowed this egg to develop on land and hatch out well-developed, terrestrial offspring. For centuries, morphologically-based studies have provided valuable information about the eggs of amniotes and the embryos that develop from them. This review explores the history of such investigations, as a contribution to this special issue of Journal of Morphology, titled Developmental Morphology and Evolution of Amniote Eggs and Embryos. Anatomically-based investigations are surveyed from the ancient Greeks through the Scientific Revolution, followed by the 19th and early 20th centuries, with a focus on major findings of historical figures who have contributed significantly to our knowledge. Recent research on various aspects of amniote eggs is summarized, including gastrulation, egg shape and eggshell morphology, eggs of Mesozoic dinosaurs, sauropsid yolk sacs, squamate placentation, embryogenesis, and the phylotypic phase of embryonic development. As documented in this review, studies on amniote eggs and embryos have relied heavily on morphological approaches in order to answer functional and evolutionary questions.
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Affiliation(s)
- Daniel G Blackburn
- Department of Biology and Electron Microscopy Center, Trinity College, Hartford, Connecticut, USA
| | - James R Stewart
- Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee, USA
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7
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Abstract
Vitellogenin (Vtg), a yolk nutrient protein that is synthesized in the livers of female animals, and subsequently carried into the ovary, contributes to vitellogenesis in oviparous animals. Thus, Vtg levels are elevated during oogenesis. In contrast, Vtg proteins have been genetically lost in viviparous mammals, thus the yolk protein is not involved in their oogenesis and embryonic development. In this study, we identified Vtg protein in the livers of females during the gestation of the viviparous teleost, Xenotoca eiseni Although vitellogenesis is arrested during gestation, biochemical assays revealed that Vtg protein was present in ovarian tissues and lumen fluid. The Vtg protein was also detected in the trophotaeniae of the intraovarian embryo. Immunoelectron microscopy revealed that Vtg protein is absorbed into intracellular vesicles in the epithelial cells of the trophotaeniae. Furthermore, extraneous Vtg protein injected into the abdominal cavity of a pregnant female was subsequently detected in the trophotaeniae of the intraovarian embryo. Our data suggest that the yolk protein is one of the matrotrophic factors supplied from the mother to the intraovarian embryo during gestation in X. eiseni.
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8
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Stewart JR, Blackburn DG. A developmental synapomorphy of squamate reptiles. Evol Dev 2019; 21:342-353. [DOI: 10.1111/ede.12317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James R. Stewart
- Department of Biological SciencesEast Tennessee State UniversityJohnson City Tennessee 37614
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9
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Martin JF, Wagner GP. The origin of platelets enabled the evolution of eutherian placentation. Biol Lett 2019; 15:20190374. [PMID: 31288683 DOI: 10.1098/rsbl.2019.0374] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Invasive placentation with extended pregnancy is a shared derived characteristic unique to eutherian mammals that possess a highly effective system of haemostasis, platelets. These are found in all mammals but no other group of animals. We propose that platelets and megakaryocytes (large polyploid nucleated bone marrow cells that produce platelets) evolved from an ancestral 2 N thrombocyte by polyploidization and that the possession of platelets enabled the evolution of invasive placentation. This could explain why invasive placentation is limited to mammals.
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Affiliation(s)
- John F Martin
- 1 Division of Medicine, University College London , London WC1E 6JF , UK.,2 Internal Medicine, Gynecology and Reproductive Sciences, Yale School of Medicine , New Haven, CT 06520 , USA
| | - Günter P Wagner
- 3 Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine , New Haven, CT 06520 , USA.,4 Department of Ecology and Evolutionary Biology, Yale University , CT 06520 , USA.,5 Systems Biology Institute , Yale West Campus, West Haven, CT 06516 , USA.,6 Department of Obstetrics and Gynecology, Wayne State University , Detroit, MI 48202 , USA
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10
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Weinell JL, Branch WR, Colston TJ, Jackman TR, Kuhn A, Conradie W, Bauer AM. A species-level phylogeny of Trachylepis (Scincidae: Mabuyinae) provides insight into their reproductive mode evolution. Mol Phylogenet Evol 2019; 136:183-195. [DOI: 10.1016/j.ympev.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/24/2019] [Accepted: 04/01/2019] [Indexed: 10/27/2022]
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11
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Novel placental structure in the Mexican gerrhonotine lizard, Mesaspis viridiflava
(Lacertilia; Anguidae). J Morphol 2018; 280:35-49. [DOI: 10.1002/jmor.20912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/21/2018] [Accepted: 10/12/2018] [Indexed: 01/27/2023]
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12
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Van Dyke JU, Griffith OW. Mechanisms of reproductive allocation as drivers of developmental plasticity in reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:275-286. [PMID: 29733527 DOI: 10.1002/jez.2165] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 04/13/2018] [Indexed: 12/30/2022]
Abstract
Developmental plasticity in offspring phenotype occurs as a result of the environmental conditions embryos experience during development. The nutritional environment provided to a fetus is an important source of developmental plasticity. Reptiles are a particularly interesting system to study this plasticity because of their varied routes of maternal nutrient allocation to reproduction. Most reptiles provide their offspring with all or most of the nutrients they require in egg yolk (lecithotrophy) while viviparous reptiles also provide their offspring with nutrients via a placenta (placentotrophy). We review the ways in which both lecithotrophy and placentotrophy can lead to differences in the nutrients embryonic reptiles receive, and discuss how these differences lead to developmental plasticity in offspring phenotype. We finish by reviewing the ecological and conservation consequences of nutritional-driven developmental plasticity in reptiles. If nutritional-driven developmental plasticity has fitness consequences, then understanding the basis of this plasticity has exciting potential to identify how reptile recruitment is affected by environmental changes in food supply. Such knowledge is critical to our ability to protect taxa threatened by environmental change.
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Affiliation(s)
- James U Van Dyke
- School of Environmental Sciences, Institute of Land, Water & Society, Charles Sturt University, Albury, NSW, Australia
| | - Oliver W Griffith
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut.,Yale Systems Biology Institute, Yale University, West Haven, Connecticut
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13
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Braz HB, Almeida-Santos SM, Murphy CR, Thompson MB. Uterine and eggshell modifications associated with the evolution of viviparity in South American water snakes (Helicopsspp.). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2018; 330:165-180. [DOI: 10.1002/jez.b.22800] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Henrique B. Braz
- School of Life and Environmental Sciences; University of Sydney; Sydney Australia
- Laboratório de Ecologia e Evolução; Instituto Butantan; São Paulo Brazil
- Departamento de Anatomia; Faculdade de Medicina Veterinária e Zootecnia; Universidade de São Paulo; São Paulo Brazil
| | - Selma M. Almeida-Santos
- Laboratório de Ecologia e Evolução; Instituto Butantan; São Paulo Brazil
- Departamento de Anatomia; Faculdade de Medicina Veterinária e Zootecnia; Universidade de São Paulo; São Paulo Brazil
| | - Christopher R. Murphy
- Discipline of Anatomy and Histology; School of Medical Science and Bosch Institute; University of Sydney; Sydney Australia
| | - Michael B. Thompson
- School of Life and Environmental Sciences; University of Sydney; Sydney Australia
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14
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An endogenous retroviral envelope syncytin and its cognate receptor identified in the viviparous placental Mabuya lizard. Proc Natl Acad Sci U S A 2017; 114:E10991-E11000. [PMID: 29162694 DOI: 10.1073/pnas.1714590114] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Syncytins are envelope genes from endogenous retroviruses that have been captured during evolution for a function in placentation. They have been found in all placental mammals in which they have been searched, including marsupials. Placental structures are not restricted to mammals but also emerged in some other vertebrates, most frequently in lizards, such as the viviparous Mabuya Scincidae. Here, we performed high-throughput RNA sequencing of a Mabuya placenta transcriptome and screened for the presence of retroviral env genes with a full-length ORF. We identified one such gene, which we named "syncytin-Mab1," that has all the characteristics expected for a syncytin gene. It encodes a membrane-bound envelope protein with fusogenic activity ex vivo, is expressed at the placental level as revealed by in situ hybridization and immunohistochemistry, and is conserved in all Mabuya species tested, spanning over 25 My of evolution. Its cognate receptor, required for its fusogenic activity, was searched for by a screening assay using the GeneBridge4 human/Chinese hamster radiation hybrid panel and found to be the MPZL1 gene, previously identified in mammals as a signal-transducing transmembrane protein involved in cell migration. Together, these results show that syncytin capture is not restricted to placental mammals, but can also take place in the rare nonmammalian vertebrates in which a viviparous placentotrophic mode of reproduction emerged. It suggests that similar molecular tools have been used for the convergent evolution of placentation in independently evolved and highly distant vertebrates.
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15
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Investigation of the clinical features of lower uterine segment carcinoma: association with advanced stage disease and indication of poorer prognosis. Arch Gynecol Obstet 2017; 297:193-198. [PMID: 29116461 DOI: 10.1007/s00404-017-4576-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 10/10/2017] [Indexed: 12/16/2022]
Abstract
PURPOSE We retrospectively analyzed the differential clinical features and prognosis of endometrial carcinomas arising from the lower uterus, which are reported to have a poorer prognosis than those arising from the upper uterus. METHODS 246 patients with endometrial carcinoma who underwent surgery were entered as subjects. RESULTS Twenty-three were classified as having lower uterine segment carcinomas (LUSC); the remaining 223 were upper uterine segment carcinomas (UUSC). LUSC cases were associated with a more advanced FIGO stage than UUSC (p < 0.001). Deep myometrial invasion and lymph node metastasis were more common in LUSC than in UUSC (p = 0.006 and p < 0.001, respectively). LUSC cases demonstrated significantly shorter overall survival (OS) and progression-free survival (PFS) than UUSC (p = 0.02 and p < 0.001, respectively). Multivariate cox proportional hazards analysis demonstrated that the hazard ratio for LUSC was 1.769 for OS and 3.479 for PFS. For endometrial carcinoma survival, FIGO stage and histological type were extracted as independent variables. CONCLUSIONS LUSC is a high-risk indicator for poorer prognosis for endometrial carcinoma because it is associated with more advanced stage disease, deep myometrial invasion and lymph node metastasis, and indicates a significantly worsened PFS probability. Our analysis concludes that LUSC is FIGO stage-dependent and an important factor for OS.
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16
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Blackburn DG, Anderson KE, Lo AR, Marquez EC, Callard IP. Placentation in watersnakes II: Placental ultrastructure in N
erodia erythrogaster
(Colubridae: Natricinae). J Morphol 2017; 278:675-688. [DOI: 10.1002/jmor.20662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 01/17/2023]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Kristie E. Anderson
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Amy R. Lo
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Emily C. Marquez
- Department of Biology; Boston University; Boston Massachusetts 02215
| | - Ian P. Callard
- Department of Biology; Boston University; Boston Massachusetts 02215
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17
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Blackburn DG, Anderson KE, Aronson KW, Burket MK, Chin JF, San-Francisco SK, Callard IP. Placentation in watersnakes I: Placental histology and development in North American Nerodia
(Colubridae: Natricinae). J Morphol 2017; 278:665-674. [DOI: 10.1002/jmor.20663] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Kristie E. Anderson
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Kera W. Aronson
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Mary K. Burket
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | - Jessica F. Chin
- Department of Biology, and Electron Microscopy Facility; Trinity College; Hartford Connecticut 06106
| | | | - Ian P. Callard
- Department of Biology; Boston University; Boston Massachusetts 02215
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18
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Roberts RM, Green JA, Schulz LC. The evolution of the placenta. Reproduction 2016; 152:R179-89. [PMID: 27486265 DOI: 10.1530/rep-16-0325] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/01/2016] [Indexed: 01/23/2023]
Abstract
The very apt definition of a placenta is coined by Mossman, namely apposition or fusion of the fetal membranes to the uterine mucosa for physiological exchange. As such, it is a specialized organ whose purpose is to provide continuing support to the developing young. By this definition, placentas have evolved within every vertebrate class other than birds. They have evolved on multiple occasions, often within quite narrow taxonomic groups. As the placenta and the maternal system associate more intimately, such that the conceptus relies extensively on maternal support, the relationship leads to increased conflict that drives adaptive changes on both sides. The story of vertebrate placentation, therefore, is one of convergent evolution at both the macromolecular and molecular levels. In this short review, we first describe the emergence of placental-like structures in nonmammalian vertebrates and then transition to mammals themselves. We close the review by discussing the mechanisms that might have favored diversity and hence evolution of the morphology and physiology of the placentas of eutherian mammals.
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Affiliation(s)
- R Michael Roberts
- C.S. Bond Life Sciences CenterUniversity of Missouri, Columbia, Missouri, USA Division of Animal SciencesUniversity of Missouri, Columbia, Missouri, USA
| | - Jonathan A Green
- Division of Animal SciencesUniversity of Missouri, Columbia, Missouri, USA
| | - Laura C Schulz
- Department of ObstetricsGynecology and Women's Health, University of Missouri School of Medicine, Columbia, Missouri, USA
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19
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Metallinou M, Weinell JL, Karin BR, Conradie W, Wagner P, Schmitz A, Jackman TR, Bauer AM. A single origin of extreme matrotrophy in African mabuyine skinks. Biol Lett 2016; 12:20160430. [PMID: 27555650 PMCID: PMC5014036 DOI: 10.1098/rsbl.2016.0430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 07/25/2016] [Indexed: 11/12/2022] Open
Abstract
Most mammals and approximately 20% of squamates (lizards and snakes) are viviparous, whereas all crocodilians, birds and turtles are oviparous. Viviparity evolved greater than 100 times in squamates, including multiple times in Mabuyinae (Reptilia: Scincidae), making this group ideal for studying the evolution of nutritional patterns associated with viviparity. Previous studies suggest that extreme matrotrophy, the support of virtually all of embryonic development by maternal nutrients, evolved as many as three times in Mabuyinae: in Neotropical Mabuyinae (63 species), Eumecia (2 species; Africa) and Trachylepis ivensii (Africa). However, no explicit phylogenetic hypotheses exist for understanding the evolution of extreme matrotrophy. Using multilocus DNA data, we inferred a species tree for Mabuyinae that implies that T. ivensii (here assigned to the resurrected genus Lubuya) is sister to Eumecia, suggesting that extreme matrotrophy evolved only once in African mabuyine skinks.
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Affiliation(s)
| | - Jeffrey L Weinell
- Department of Biology, Villanova University, Villanova, PA 19085, USA
| | - Benjamin R Karin
- Department of Biology, Villanova University, Villanova, PA 19085, USA
| | - Werner Conradie
- Port Elizabeth Museum (Bayworld), Port Elizabeth, South Africa
| | | | - Andreas Schmitz
- Department of Herpetology and Ichthyology, Natural History Museum of Geneva, Geneva, Switzerland
| | - Todd R Jackman
- Department of Biology, Villanova University, Villanova, PA 19085, USA
| | - Aaron M Bauer
- Department of Biology, Villanova University, Villanova, PA 19085, USA
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Kim YK, Blackburn DG. Fetal Membrane Ultrastructure and Development in the Oviparous MilksnakeLampropeltis triangulum(Colubridae) with Reference to Function and Evolution in Snakes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 326:290-302. [DOI: 10.1002/jez.b.22684] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 05/31/2016] [Accepted: 06/10/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Young K. Kim
- Department of Biology and Electron Microscopy Facility; Trinity College; Hartford Connecticut
| | - Daniel G. Blackburn
- Department of Biology and Electron Microscopy Facility; Trinity College; Hartford Connecticut
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21
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Blackburn DG. History of reptile placentology II: WilhelmHaacke’s 1885 account of lizard viviparity. ZOOL ANZ 2016. [DOI: 10.1016/j.jcz.2016.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Furness AI, Morrison KR, Orr TJ, Arendt JD, Reznick DN. Reproductive mode and the shifting arenas of evolutionary conflict. Ann N Y Acad Sci 2015; 1360:75-100. [PMID: 26284738 DOI: 10.1111/nyas.12835] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/21/2015] [Accepted: 06/05/2015] [Indexed: 12/11/2022]
Abstract
In sexually reproducing organisms, the genetic interests of individuals are not perfectly aligned. Conflicts among family members are prevalent since interactions involve the transfer of limited resources between interdependent players. Intrafamilial conflict has traditionally been considered along three major axes: between the sexes, between parents and offspring, and between siblings. In these interactions, conflict is expected over traits in which the resulting phenotypic value is determined by multiple family members who have only partially overlapping fitness optima. We focus on four major categories of animal reproductive mode (broadcast spawning, egg laying, live bearing, and live bearing with matrotrophy) and identify the shared phenotypes or traits over which conflict is expected, and then review the empirical literature for evidence of their occurrence. Major transitions among reproductive mode, such as a shift from external to internal fertilization, an increase in egg-retention time, modifications of embryos and mothers for nutrient transfer, the evolution of postnatal parental care, and increased interaction with the kin network, mark key shifts that both change and expand the arenas in which conflict is played out.
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Affiliation(s)
- Andrew I Furness
- Department of Biology, University of California, Riverside, California.,Department of Ecology and Evolutionary Biology, University of California, Irvine, California
| | - Keenan R Morrison
- Department of Biology, University of California, Riverside, California
| | - Teri J Orr
- Department of Biology, University of California, Riverside, California.,Department of Biology, University of Massachusetts, Amherst, Massachusetts
| | - Jeff D Arendt
- Department of Biology, University of California, Riverside, California
| | - David N Reznick
- Department of Biology, University of California, Riverside, California
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23
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Mechanisms of Evolutionary Innovation Point to Genetic Control Logic as the Key Difference Between Prokaryotes and Eukaryotes. J Mol Evol 2015. [PMID: 26208881 DOI: 10.1007/s00239-015-9688-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The evolution of life from the simplest, original form to complex, intelligent animal life occurred through a number of key innovations. Here we present a new tool to analyze these key innovations by proposing that the process of evolutionary innovation may follow one of three underlying processes, namely a Random Walk, a Critical Path, or a Many Paths process, and in some instances may also constitute a "Pull-up the Ladder" event. Our analysis is based on the occurrence of function in modern biology, rather than specific structure or mechanism. A function in modern biology may be classified in this way either on the basis of its evolution or the basis of its modern mechanism. Characterizing key innovations in this way helps identify the likelihood that an innovation could arise. In this paper, we describe the classification, and methods to classify functional features of modern organisms into these three classes based on the analysis of how a function is implemented in modern biology. We present the application of our categorization to the evolution of eukaryotic gene control. We use this approach to support the argument that there are few, and possibly no basic chemical differences between the functional constituents of the machinery of gene control between eukaryotes, bacteria and archaea. This suggests that the difference between eukaryotes and prokaryotes that allows the former to develop the complex genetic architecture seen in animals and plants is something other than their chemistry. We tentatively identify the difference as a difference in control logic, that prokaryotic genes are by default 'on' and eukaryotic genes are by default 'off.' The Many Paths evolutionary process suggests that, from a 'default off' starting point, the evolution of the genetic complexity of higher eukaryotes is a high probability event.
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24
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Blackburn DG, Starck JM. Morphological specializations for fetal maintenance in viviparous vertebrates: An introduction and historical retrospective. J Morphol 2015; 276:E1-16. [DOI: 10.1002/jmor.20410] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 05/11/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology; and Electron Microscopy Center; Trinity College; Hartford Connecticut 06106
| | - J. Matthias Starck
- Department of Biology; University of Munich; D-82152 Planegg-Martinsried Germany
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25
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Blackburn DG. Viviparous placentotrophy in reptiles and the parent-offspring conflict. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:532-48. [DOI: 10.1002/jez.b.22624] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Daniel G. Blackburn
- Departmentof Biology; Electron Microscopy Center; Trinity College; Hartford Connecticut
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26
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Blackburn DG. Evolution of viviparity in squamate reptiles: Reversibility reconsidered. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:473-86. [DOI: 10.1002/jez.b.22625] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/20/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology, Electron Microscopy Center; Trinity College; Hartford Connecticut
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27
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Griffith OW, Blackburn DG, Brandley MC, Van Dyke JU, Whittington CM, Thompson MB. Ancestral state reconstructions require biological evidence to test evolutionary hypotheses: A case study examining the evolution of reproductive mode in squamate reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:493-503. [DOI: 10.1002/jez.b.22614] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/18/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Oliver W. Griffith
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | | | - Matthew C. Brandley
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | - James U. Van Dyke
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | - Camilla M. Whittington
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
| | - Michael B. Thompson
- School of Biological Sciences; Heydon Laurence Building (A08); University of Sydney; Camperdown NSW Australia
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28
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Iida A, Nishimaki T, Sehara-Fujisawa A. Prenatal regression of the trophotaenial placenta in a viviparous fish, Xenotoca eiseni. Sci Rep 2015; 5:7855. [PMID: 25598151 PMCID: PMC4297964 DOI: 10.1038/srep07855] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 12/16/2014] [Indexed: 11/09/2022] Open
Abstract
The trophotaenial placenta is a branching, ribbon-like structure that extends from the perianal region of the embryo in viviparous teleost fishes belonging to the family Goodeidae. It is a hindgut-derived pseudoplacenta, which contributes to absorbing maternal nutrients during the prenatal stage. The trophotaeniae are known to reduce at birth; however, no previous study has evaluated the removal mechanisms. We report here the analysis of the trophotaeniae using the goodeid fish species Xenotoca eiseni. The X. eiseni trophotaenia consists of an epidermal cell layer, mesenchyme, vasculature, and circulating erythrocytes. The trophotaeniae had preliminary regressed when the embryo was born. Immunohistochemistry indicated that caspase3-activated cells with fragmented nuclei are present in the regressed processes of the fry immediately after birth, but not in the vasculature and blood cells. This finding suggests that the trophotaenia is rapidly resorbed by apoptosis in the last phase of the pregnancy and that its circulatory pathway is maintained. Such prenatal regression of pseudoplacentae has not been reported in other viviparous vertebrates. On the other hand, similar apoptotic remodeling in the gut has been reported in amphibians, which is regulated by thyroid hormone. Thus, apoptotic regression of the trophotaeniae might occur in a manner similar to amphibian metamorphosis.
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Affiliation(s)
- Atsuo Iida
- Department of Growth Regulation, Institute for Frontier Medical Sciences, Kyoto University, Kawahara-cho 53, Shogo-in, Kyoto 606-8507, Japan
| | - Toshiyuki Nishimaki
- Department of Anatomy, Kitasato University School of Medicine 1-15-1 Kitasato, Sagamihara Kanagawa 228-8555, Japan
| | - Atsuko Sehara-Fujisawa
- Department of Growth Regulation, Institute for Frontier Medical Sciences, Kyoto University, Kawahara-cho 53, Shogo-in, Kyoto 606-8507, Japan
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29
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Wu Q, Fong CK, Thompson MB, Murphy CR. Changes to the uterine epithelium during the reproductive cycle of two viviparous lizard species (Niveoscincusspp.). ACTA ZOOL-STOCKHOLM 2014. [DOI: 10.1111/azo.12096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Qiong Wu
- School of Biological Sciences (A08); The University of Sydney; Sydney NSW 2006 Australia
| | - Cameron K. Fong
- School of Medical Sciences (Anatomy and Histology) and Bosch Institute; The University of Sydney; Sydney NSW 2006 Australia
| | - Michael B. Thompson
- School of Biological Sciences (A08); The University of Sydney; Sydney NSW 2006 Australia
| | - Christopher R. Murphy
- School of Medical Sciences (Anatomy and Histology) and Bosch Institute; The University of Sydney; Sydney NSW 2006 Australia
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Van Dyke JU, Griffith OW, Thompson MB. High Food Abundance Permits the Evolution of Placentotrophy: Evidence from a Placental Lizard, Pseudemoia entrecasteauxii. Am Nat 2014; 184:198-210. [DOI: 10.1086/677138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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31
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Blackburn DG. Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis. J Morphol 2014; 276:961-90. [DOI: 10.1002/jmor.20272] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 01/27/2014] [Accepted: 02/09/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Daniel G. Blackburn
- Department of Biology and; Electron Microscopy Center, Trinity College; Hartford Connecticut 06106
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32
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Van Dyke JU, Brandley MC, Thompson MB. The evolution of viviparity: molecular and genomic data from squamate reptiles advance understanding of live birth in amniotes. Reproduction 2014; 147:R15-26. [DOI: 10.1530/rep-13-0309] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Squamate reptiles (lizards and snakes) are an ideal model system for testing hypotheses regarding the evolution of viviparity (live birth) in amniote vertebrates. Viviparity has evolved over 100 times in squamates, resulting in major changes in reproductive physiology. At a minimum, all viviparous squamates exhibit placentae formed by the appositions of maternal and embryonic tissues, which are homologous in origin with the tissues that form the placenta in therian mammals. These placentae facilitate adhesion of the conceptus to the uterus as well as exchange of oxygen, carbon dioxide, water, sodium, and calcium. However, most viviparous squamates continue to rely on yolk for nearly all of their organic nutrition. In contrast, some species, which rely on the placenta for at least a portion of organic nutrition, exhibit complex placental specializations associated with the transport of amino acids and fatty acids. Some viviparous squamates also exhibit reduced immunocompetence during pregnancy, which could be the result of immunosuppression to protect developing embryos. Recent molecular studies using both candidate-gene and next-generation sequencing approaches have suggested that at least some of the genes and gene families underlying these phenomena play similar roles in the uterus and placenta of viviparous mammals and squamates. Therefore, studies of the evolution of viviparity in squamates should inform hypotheses of the evolution of viviparity in all amniotes, including mammals.
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Griffith O, Van Dyke J, Thompson M. No implantation in an extra-uterine pregnancy of a placentotrophic reptile. Placenta 2013; 34:510-1. [DOI: 10.1016/j.placenta.2013.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 02/26/2013] [Accepted: 03/04/2013] [Indexed: 11/15/2022]
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34
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Renfree MB, Suzuki S, Kaneko-Ishino T. The origin and evolution of genomic imprinting and viviparity in mammals. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120151. [PMID: 23166401 DOI: 10.1098/rstb.2012.0151] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Genomic imprinting is widespread in eutherian mammals. Marsupial mammals also have genomic imprinting, but in fewer loci. It has long been thought that genomic imprinting is somehow related to placentation and/or viviparity in mammals, although neither is restricted to mammals. Most imprinted genes are expressed in the placenta. There is no evidence for genomic imprinting in the egg-laying monotreme mammals, despite their short-lived placenta that transfers nutrients from mother to embryo. Post natal genomic imprinting also occurs, especially in the brain. However, little attention has been paid to the primary source of nutrition in the neonate in all mammals, the mammary gland. Differentially methylated regions (DMRs) play an important role as imprinting control centres in each imprinted region which usually comprises both paternally and maternally expressed genes (PEGs and MEGs). The DMR is established in the male or female germline (the gDMR). Comprehensive comparative genome studies demonstrated that two imprinted regions, PEG10 and IGF2-H19, are conserved in both marsupials and eutherians and that PEG10 and H19 DMRs emerged in the therian ancestor at least 160 Ma, indicating the ancestral origin of genomic imprinting during therian mammal evolution. Importantly, these regions are known to be deeply involved in placental and embryonic growth. It appears that most maternal gDMRs are always associated with imprinting in eutherian mammals, but emerged at differing times during mammalian evolution. Thus, genomic imprinting could evolve from a defence mechanism against transposable elements that depended on DNA methylation established in germ cells.
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Affiliation(s)
- Marilyn B Renfree
- Department of Zoology, The University of Melbourne, Victoria 3010, Australia.
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35
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Chaouat G. Inflammation, NK cells and implantation: friend and foe (the good, the bad and the ugly?): replacing placental viviparity in an evolutionary perspective. J Reprod Immunol 2013; 97:2-13. [PMID: 23347505 DOI: 10.1016/j.jri.2012.10.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/25/2012] [Accepted: 10/01/2012] [Indexed: 01/14/2023]
Abstract
This review summarises an invited talk presented at the 2012 ESRI/ASRI meeting in Hamburg, concerning current views of inflammation in pregnancy, which is timely given that the effects of a local injury in the uterus acts to favour implantation. Recalling that inflammation can be good (it is useful and necessary for implantation), bad (in implantation failure, RSA) and ugly (at the extreme, endometriosis is associated with pain and infertility) leads to consideration of its status in pregnancy. Its role in implantation and the fact that pregnancy maintains some aspects of inflammation throughout, leads to revision of not only concepts of immunosuppression and the Th1/Th2 paradigm, but also the feto-maternal relationship as seen since Medawar's hypotheses were advanced. This is examined from an evolutionary perspective, which should lead to further review of our perception of uterine NK cells, and the emergence of Treg cells to control some aspects of adaptive immunity, which appeared long after placentation.
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Affiliation(s)
- Gérard Chaouat
- U 976 INSERM, Pavillon Equerre Bazin, Hôpital Saint Louis, Paris, France.
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36
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Schuett GW, Repp RA, Amarello M, Smith CF. Unlike most vipers, female rattlesnakes(Crotalus atrox)continue to hunt and feed throughout pregnancy. J Zool (1987) 2012. [DOI: 10.1111/j.1469-7998.2012.00969.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - R. A. Repp
- National Optical Astronomy Observatory; Tucson; AZ; USA
| | - M. Amarello
- School of Life Sciences; Arizona State University; Tempe; AZ; USA
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37
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Development of yolk sac and chorioallantoic membranes in the Lord Howe Island skink, Oligosoma lichenigerum. J Morphol 2012; 273:1163-84. [DOI: 10.1002/jmor.20052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/30/2012] [Accepted: 05/20/2012] [Indexed: 12/16/2022]
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38
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Brandley MC, Young RL, Warren DL, Thompson MB, Wagner GP. Uterine gene expression in the live-bearing lizard, Chalcides ocellatus, reveals convergence of squamate reptile and mammalian pregnancy mechanisms. Genome Biol Evol 2012; 4:394-411. [PMID: 22333490 PMCID: PMC3318437 DOI: 10.1093/gbe/evs013] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2012] [Indexed: 12/18/2022] Open
Abstract
Although the morphological and physiological changes involved in pregnancy in live-bearing reptiles are well studied, the genetic mechanisms that underlie these changes are not known. We used the viviparous African Ocellated Skink, Chalcides ocellatus, as a model to identify a near complete gene expression profile associated with pregnancy using RNA-Seq analyses of uterine transcriptomes. Pregnancy in C. ocellatus is associated with upregulation of uterine genes involved with metabolism, cell proliferation and death, and cellular transport. Moreover, there are clear parallels between the genetic processes associated with pregnancy in mammals and Chalcides in expression of genes related to tissue remodeling, angiogenesis, immune system regulation, and nutrient provisioning to the embryo. In particular, the pregnant uterine transcriptome is dominated by expression of proteolytic enzymes that we speculate are involved both with remodeling the chorioallantoic placenta and histotrophy in the omphaloplacenta. Elements of the maternal innate immune system are downregulated in the pregnant uterus, indicating a potential mechanism to avoid rejection of the embryo. We found a downregulation of major histocompatability complex loci and estrogen and progesterone receptors in the pregnant uterus. This pattern is similar to mammals but cannot be explained by the mammalian model. The latter finding provides evidence that pregnancy is controlled by different endocrinological mechanisms in mammals and reptiles. Finally, 88% of the identified genes are expressed in both the pregnant and the nonpregnant uterus, and thus, morphological and physiological changes associated with C. ocellatus pregnancy are likely a result of regulation of genes continually expressed in the uterus rather than the initiation of expression of unique genes.
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