how do viviparity and the placenta affect mammalian reproduction?

Oestrogen in the maternal brain is converted to pregnenalone, which serves as a maternal anxiolytic. If you're interested, ask to see the placenta. Human endogenous retroviruses: friend or foe? volume113,pages 138144 (2014)Cite this article. Please enable it to take advantage of the complete set of features! Evolution of Oviductal Gestation in Amphibians. Structure Placental mammals, including humans, have a chorioallantoic placenta that forms from the chorion and allantois. However, viviparity and placental growth call for higher energy and resources from the mother, which can pose a possible trade-off in terms of her own survival and breeding success. Updates? They are transcribed from multiple, structurally conserved genes that have probably arisen by duplications and gene conversion events from another Type 1 IFN gene, interferon omega (IFNW). Imprinted genes in mouse placental development and the regulation of fetal energy stores. In the vertebrate tree of life, viviparity or live birth has independently evolved many times, resulting in a rich diversity of reproductive strategies. Foetal leydig cell production of testosterone counteracts the maternalising influence of placental hormones and masculinises the male hypothalamus, an effect that continues into the early post-partum period when foetal leydig cells subsequently undergo apoptosis (Keverne, 2012). 1997; Pough et al. Placental pathology. The Evolution of the Placenta - PMC - National Center for Biotechnology 2014). Chapter 35 Deuterostome Animals Flashcards | Quizlet In addition to functional co-adaptation between the foetal placenta and maternal immune system, there is also functional co-adaptation across the placenta and developing brain, most notably the developing hypothalamus. H19 may have tumour-suppressor activity when combined with Igf2, whereas Peg10 encodes a protein with homologies to retrotransposons. In addition to providing resources from mother over lengthy pregnancies, the placenta has to hormonally prime the mothers hypothalamus to ensure maternal care and provision of milk. (2010). The authors concluded that these results do not provide genetic support for imprinted genes being involved in antagonistic co-evolution via a parental conflict. With placenta accreta, part or all of the placenta remains firmly attached to the uterus. For example, in the straight-nosed pipefish Nerophis ophidion, eggs stick to the epithelium of the fathers pouch, which is open to the sea environment (Carcupino, et al. Proc Natl Acad Sci USA 108: 1523715241. (2010). 2013 Nov 20;147(1):R15-26. Thus, the foetus controls its own destiny in times of acute starvation, especially in the last trimester of pregnancy, by short-term sacrifice of its placenta to preserve resources critical for brain development. 1997, Roberts, et al. Analysis of the platypus genome suggests a transposon origin for mammalian imprinting. Maternal efforts to counteract the acquisitiveness of the fetus may lead to the evolution of oppositely imprinted genes. Cell 137: 11941211. Dev Neurobiol 69: 314325. The placenta and the pace of life - The Conversation As a library, NLM provides access to scientific literature. Chess A . Cross JC, Baczyk D, Dobric N, Hemberger M, Hughes M, Simmons DG, Yamamoto H, Kingdom JC. Reproduction 136: 523531. In another similarity to the eutherians, the placenta of the tammar wallaby secretes a complement of hormones that include IGF2 and relaxin, which, in that species, may be responsible for the phenomenon of maternal recognition of pregnancy (Renfree 2010). It should be stressed that the perceived disadvantages of extended diffusion distances for dissolved gases and solutes encountered with a superficial placenta, like that of the pig, are largely illusory. Longmans, London, pp 127311, Bell AW, Ehrhardt RA (2002) Regulation of placental nutrient transport and implications for fetal growth. In eutherian mammals, some 55 imprinted genes have been reported as expressed in the more invasive, longer-lived placenta (Tunster et al., 2013). Keverne EB . Moore KL, et al. Epub 2020 Apr 8. Accessed Feb. 6, 2020. The .gov means its official. In most species the GH gene is single copy, but in humans, there are five members, one restricted in expression to the pituitary, the other four to the placenta (Haig 2008). Viviparity is believed to be a mode of reproduction that evolved from the ancestral condition of oviparity or egg laying, where most of the fetal development occurs outside the body. An official website of the United States government. As such it is a specialized organ whose purpose is to provide continuing support to the developing young. Haig D. Genetic conflicts in human pregnancy. Mechanisms and consequences of widespread random monoallelic expression. Yolkless Egg and the Evolution of Eutherian Viviparity Whether embryo-derived placental cells of other animals, which, unlike mammals, do not form an initiating trophectoderm, should be termed trophoblast is therefore questionable, despite many shared functions. The co-existence of three matrilineal generations as one (mother . During pregnancy, possible placental problems include placental abruption, placenta previa and placenta accreta. Article The placenta is a structure that develops in the uterus during pregnancy. Chen Z, Hagen DE, Wang J, Elsik CG, Ji T, Siqueira LG, Hansen PJ, Rivera RM. Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis. (2008). HHS Vulnerability Disclosure, Help (2005). Proc Biol Sci 264: 739746. Although decidual NK cells are in close contact with foetal trophoblast, they do not exert cytolytic functions because of activation of inhibitory killer cell immunoglobulin-like receptors on the surface of these maternal immune cells. Reproduction takes many forms but the 3 main methods are: OVIPARITY (egg-laying) Skate, chimaera and some shark species produce eggs encased in a tough 'leathery' eggcase. (2006). As a result, the fate of most ERVs is gradual genetic degradation through mutation and homologous recombination. Mammal - Reproduction & social behavior | Britannica Invasive implantation and intimate placental associations in a placentotrophic african lizard, Trachylepis ivensi (scincidae). Yet, despite these apparently conserved functions placentas are arguably the least conserved and most rapidly evolving mammalian organs. In: Encyclopedia of reproduction. In the mouse, they have diverse patterns of spatial and temporal expression (Simmons, et al. A couple of examples illustrate the kind of strategies used in apes, where implantation occurs immediately after the blastocyst attaches, and in artiodactyls where implantation is superficial and delayed. Although placentation arose once in the common ancestor of mammals, it has arisen independently multiple times within other classes, and even families. Architecture of the human gene regulatory network derived from ENCODE data. Genome Biol 10: R1. Evolution of the placenta during the early radiation of placental mammals. Article Another member of the Sox gene family (Sox15) has 75% sequence in common with Sox3 and is also expressed in the placenta. The organ is usually attached to the top, side, front or back of the uterus. Google Scholar. These same placental hormones induce nest building in advance of birth and also prime the hypothalamus for post-partum maternal care and milk letdown (Figure 1). Nutr Res Rev 15(2):211230 2019 Apr 26;15(4):20180827. doi: 10.1098/rsbl.2018.0827. (2012). Placenta previa and accreta, vasa previa, subchorionic hemorrhage and abruptio placentae. The recent encode of the human genome investigated the link between allele-specific binding and allele-specific expression, and have identified maternal-specific networks (Gerstein et al., 2012). Placental mammals produce small numbers of large offspring. Animal Reproduction - Early Development Early Development Once the gametes have successfully fused, the embryo can begin to develop. 2005). All rights reserved. FOXL2 versus SOX9: a lifelong battle of the sexes. 2008) and appear to target the maternal endometrium (Soares, et al. A maternal-offspring coadaptation theory for the evolution of genomic imprinting. These kinds of network interaction often favour the evolution of genetic co-adaptation where beneficially interacting alleles evolve to become co-inherited. The IFNT proteins are secreted from mononucleated trophoblasts and act on the uterus by binding to type I interferon receptors, with the period of release occurring before the trophoblast has formed definite attachment to the uterine epithelium (Bazer, et al. In the relatively short-lived marsupial placenta, H19 is methylated on the paternal chromosome and Igf2 is also expressed from the paternal chromosome but there is no methylation imprinting of the Igf2 receptor (Renfree et al., 2008). The https:// ensures that you are connecting to the 2002), while in the potbellied seahorse Hippocampus abdominalis, the pouch is sealed and its epithelium highly folded, thinned, and vascularized, (Carcupino, et al. The co-adaptive development of the placenta and maternal hypothalamus has required a concomitant evolutionary development to ensure masculinisation of the male hypothalamus (Keverne, 2013). Not only have more genes been recruited to ICRs, but many of these genes form extensive networks with other imprinted genes (Sumida and Ohlsson, 2010). Of necessity, many important references cannot be cited in a short review of this kind. An extensive literature has developed around this topic, with particular emphasis on the role played by imprinted genes in controlling nutrient supply and growth of the fetus (Reik, et al. Placenta and fetal membranes. Amey KL, Bae E, Olsen C, Drewell RA . Proceedings of the Zoological Society of London. Implantation and Placentation Vol 2, Reproduction in Mammals: Embryonic and Fetal Development. The Gene of Retroviral Origin Syncytin 1 is Specific to Hominoids and is Inactive in Old World Monkeys. Theory has been very helpful in conceptualising the evolutionary significance of genomic imprinting at a time when little empirical data were available. 15.5 and 15.7 from E.C. There is no direct contact between mother and the embryo, only with the extra-embryonic placental trophoblast as it implants and develops in the uterus. Also products of multi-gene families likely overlap in function, so that a loss of one gene may be compensated by the presence of one or more of its orthologs. Most theories have failed to take into account the epigenetic mechanisms for genomic imprinting, which has itself become heritable and expressed primarily through the maternal germline. Various factors can affect the health of the placenta during pregnancy. (2011). Expression and function of endogenous retroviruses in the placenta. In some taxa this includes the evolution of a specialized interface, the placenta, between fetal and maternal tis- This prevents the binding of a maternal protein, CCCTC binding protein (CTCF), which is integral to paternal Igf2 expression. Typically, the placenta detaches from the uterine wall after childbirth. 2015). Moreover, this and similar trees based on other features of the placenta strongly imply that the placenta of the last common eutherian ancestor was discoid, either hemochorial or endotheliochorial (Mess and Carter 2007), and possessed a labyrinth-type type of placental interdigitation. Epigenetics 7: 361369. Mammalian Structure and Function: Reproduction - UMD viviparity, retention and growth of the fertilized egg within the maternal body until the young animal, as a larva or newborn, is capable of independent existence. Careers. 2002), thereby allowing exchange of nutrients. The evolution of functionally novel proteins after gene duplication. Friess AE, Sinowatz F, Skolek-Winnisch R, Trautner W. The placenta of the pig. Imprinted silencing is extended over broad chromosomal domains in mouse extra-embryonic lineages. 2019; doi:10.1055/s-0038-1657782. In the marsupial blastocyst, blastomeres adhere to the inner surface of the zona pellucida, resulting first in a cup-shaped blastocyst, and then a hollow sphere, with no discernible inner cell mass (Selwood and Johnson 2006). Any remaining fragments must be removed from the uterus to prevent bleeding and infection. Thus, errors may be absorbed and robustness prevails in such fundamental biological systems (Sandhu, 2010). Among stingrays, fingerlike projections of the uterine wall, termed trophonemata, provide histotrophic nutrition to the developing embryo (Hamlett, et al. Lin C, Lin M, Chen H. Biochemical characterization of the human placental transcription factor GCMa/1. In: Moffett A, Loke C, McLaren A (eds) Biology and Pathology of Trophoblast. Challenging this genomic linkage of hypothalamic and placental expression with 24-h maternal food deprivation late in pregnancy (E13 mouse) results in disruption of co-expressed genes, primarily by affecting those expressed in the placenta (Broad and Keverne, 2011). Placental Transport and Distribution of Uteroferrin in the Fetal Pig. 2). Accessed Feb. 6, 2020. Accessed Feb. 7, 2020. A C-section delivery might be required. 1982). Curley JP, Barton SC, Surani AM, Keverne EB . By contrast, there is only a single copy of the PRL gene in the human, whereas there are 23 members in the mouse, 24 in the rat, and 12 in cattle (Haig 1993). 2007) and is also believed to be involved in trophoblast fusion events through interaction with another transporter protein, MFSD2. The monotremes branched early from other mammals and do not have the teats seen in most mammals, but they do have mammary glands. CTCF: master weaver of the genome. In reproductively mature female mammals, an interaction of hormones from the pituitary gland and the ovaries produces a phenomenon known as the estrous cycle. How do viviparity and the placenta affect mammalian reproduction Imprinted genes show unique patterns of sequence conservation. (2006). This biased change to gene dysregulation in the placenta is linked to autophagy and ribosomal turnover, which sustains, in the short term, nutrient supply for the developing hypothalamus. (2013). Meiotic recombination, which is high at ICRs, results in accumulation of CpG sites through biased conversions that favour AT-GC mutations, whereas C-T deamination in the paternal germline has failed to sustain paternal ICRs (Duret and Galtier, 2009). Certainly, in the context of genomic imprinting, it is the heritable epigenetic non-coding ICR, which are of primary evolutionary significance.
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