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Sex Determination And Differentiation In Insects
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Book Synopsis Sex Determination and Differentiation in Insects by : E. C. Verhulst
Download or read book Sex Determination and Differentiation in Insects written by E. C. Verhulst and published by S. Karger AG (Switzerland). This book was released on 2014-03-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three conditions are essential for evolution: variation, heredity and time. Most animal species transmit genetic information through sexual reproduction in order to meet the first two conditions. The consequence for sexual reproduction is the need for (at least) two sexes with different reproductive roles. Consequently, evolutionary issues arise, such as differences in morphological and behavioral attributes between the sexes, which are reflected in the plethora of animal sex-determining systems. Indeed, a transition to asexual development may occur, sometimes induced by microbial endosymbionts. All these aspects are represented in the insect sex-determining system, which is the focal topic of this issue of Sexual Development. Sex Determination and Differentiation in Insects is recommended to scientists interested in the evolution of sex determination in particular and developmental pathways in general.
Book Synopsis The Evolutionary Origins of an Insect Sexual Differentiation Pathway Based on Sex-specific Alternative Splicing by : Judith Rachel Wexler
Download or read book The Evolutionary Origins of an Insect Sexual Differentiation Pathway Based on Sex-specific Alternative Splicing written by Judith Rachel Wexler and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Model organisms heavily skew our understanding of developmental biology. We have a detailed understanding of the developmental pathways in select taxa that have for decades been the subject of detailed research, but we have little understanding of how these pathways evolve over time. Because of its relatively rapid evolution, the sexual differentiation pathway presents an excellent model to study developmental pathway evolution. Several factors make this pathway an ideal model for study in insects: a unique, insect specific mode of sexual development based around alternative RNA splicing in insects, comprehensive knowledge of sexual differentiation in derived insect groups, and tractable insect models throughout the insect phylogeny. In this thesis, I investigate in three parts the evolution of an insect sexual differentiation pathway based on sex-specific RNA splicing: first, I study the phylogenetic distribution of two key arthropod sex determination genes – doublesex and transformer; second, I look at the spliceforms of these genes in several hemimetabolous insect orders; and third, I evaluated the function of these genes using RNAi knockdowns in the German cockroach, Blattella germanica. I first find that orthologs of a large portion of sex determination genes are phylogenetically restricted, suggesting lineage specific diversification of these developmental regulators. Second, I find deeper conservation of sex specific splicing of doublesex than of the transformer. As transformer is above doublesex in the insect sex determination cascade, this finding supports a previously posited hypothesis about sex determination genes at the bottom of a pathway being more conserved than those above it. Third, I find roles for doublesex and transformer in cockroaches that suggest sexual differentiation in hemimetabolous insects might represent an intermediate state between crustaceans and holometabolous insects.
Book Synopsis Sex Determination and Sexual Development by :
Download or read book Sex Determination and Sexual Development written by and published by Academic Press. This book was released on 2009-01-19 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews our current understanding for how sex determination is initiated and how it results in sexual dimorphic development. Chapters discussing work on different model systems provide a basis for understanding similarities that exist between different species. Coverage includes discussion of sexual development of the soma in C. elegans; sexual development of the germline in C. elegans; sexual development of the soma in Drosophila; sexual development of the germline in Drosophila; sexual development of the soma in the mouse; sexual development of the germline in the mouse; control of sex-specific behavior in Drosophila; and control of sex-specific behavior in vertebrates. - Uncovers the latest research findings on sexual determination and sexual development - Model systems illustrate key sexual similarities - Explores in-depth the origins of sex specific behavior
Book Synopsis Insects and the Evolution of Developmental Pathways by : Josefine Just
Download or read book Insects and the Evolution of Developmental Pathways written by Josefine Just and published by . This book was released on 2019 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural selection alters genetic pathways over evolutionary time. However, different pathways have been shown to maintain mutations at varying rates, leading to different levels of conservation across developmental pathways. Sex determination pathways, in particular, show vast diversity across animals despite the fundamental conservation of biological sex itself. Here, I investigated the sex determination pathway of the hemimetabolous insect, Oncopeltus fasciatus. The large milkweed bug, O. fasciatus, is part of the order Hemiptera, which provides a relevant outgroup study to other insects in which sex determination has been studied to date. I studied three sex determination genes, intersex, fruitless, and three paralogs of doublesex via a set of phylogenetic sequence comparisons, qRT-PCR gene expression studies, and RNAi functional analyses. I report that somatic sex differentiation requires these genes in a tissue- specific manner. Additionally, the doublesex locus might be less conserved than intersex and fruitless. intersex and all three doublesex paralogs appear to be moderately expressed during key time periods of sex determination in O. fasciatus specimens. Finally, I find that intersex, fruitless, and doublesex-c (or potentially all three doublesex paralogs in males) are required for the determination and development of two sexual dimorphisms in O. fasciatus in tissue-specific combinations. All three target genes appear to be required for sex determination and development in both sexes of O. fasciatus. These results indicate novel functions and/or locus evolution of intersex, fruitless, and doublesex in O. fasciatus compared to other insects, indicating evolution of the sex determination pathway within the insect lineage.
Book Synopsis The Evolution of Sex Determination by : Leo W. Beukeboom
Download or read book The Evolution of Sex Determination written by Leo W. Beukeboom and published by . This book was released on 2014 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sexual reproduction is a fundamental aspect of life. It is defined by the occurrence of meiosis and the fusion of two gametes of different sexes or mating types. Sex-determination mechanisms are responsible for the sexual fate and development of sexual characteristics in an organism, be it a unicellular alga, a plant, or an animal. In many cases, sex determination is genetic: males and females have different alleles or different genes that specify their sexual morphology. In animals, this is often accompanied by chromosomal differences. In other cases, sex may be determined by environmental (e.g. temperature) or social variables (e.g. the size of an organism relative to other members of its population). Surprisingly, sex-determination mechanisms are not evolutionarily conserved but are bewilderingly diverse and appear to have had rapid turnover rates during evolution. Evolutionary biologists continue to seek a solution to this conundrum. What drives the surprising dynamics of such a fundamental process that always leads to the same outcome: two sex types, male and female? The answer is complex but the ongoing genomic revolution has already greatly increased our knowledge of sex-determination systems and sex chromosomes in recent years. This novel book presents and synthesizes our current understanding, and clearly shows that sex-determination evolution will remain a dynamic field of future research. The Evolution of Sex Determination is an advanced, research level text suitable for graduate students and researchers in genetics, developmental biology, and evolution.
Book Synopsis Studies in Spermatogenesis by : Nettie Maria Stevens
Download or read book Studies in Spermatogenesis written by Nettie Maria Stevens and published by . This book was released on 1905 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Sex Determination, Differentiation and Intersexuality in Placental Mammals by : R. H. F. Hunter
Download or read book Sex Determination, Differentiation and Intersexuality in Placental Mammals written by R. H. F. Hunter and published by Cambridge University Press. This book was released on 1995-03-09 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: How do males become male and females become female? And what are the consequences if the decision is not incisive? Drawing upon interests in animal genetics and molecular biology, the author endeavours to answer these difficult yet fascinating questions. Originally published in 1995, this book describes the genetic determination of sex and examines how sexual organs are differentiated. Using examples of intersexuality, chimaeras and asymmetries, the book describes the underlying molecular basis of sex determination and sexual differentiation, and focuses on the critical role of the rate of embryonic development in these vital processes. Male precocity is a recurrent theme, as is the involvement of Sertoli cells and their secretion of anti-Müllerian hormone. An invaluable book for reproductive physiologists, geneticists and developmental biologists whose interests may extend from animal science through veterinary medicine to human clinical medicine.
Book Synopsis The Mechanism and Physiology of Sex Determination by : Richard Goldschmidt
Download or read book The Mechanism and Physiology of Sex Determination written by Richard Goldschmidt and published by . This book was released on 1923 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Insect Accessory Reproductive Structures by : M.S. Kaulenas
Download or read book Insect Accessory Reproductive Structures written by M.S. Kaulenas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: In retrospect, the range of topics covered in this monograph, although forming a coherent ensemble, is so extensive that a detailed discussion could easily extend to three or four times the current length. My approach has been to identify the critical issues, summarize the major accomplishments, and to suggest promising avenues for future research. To facilitate this sum mary presentation, I have limited the literature review largely to material published after 1970, extending to material appearing late in 1990. I gratefully acknowledge the advice of many colleagues, particularly the valuable criticisms of Drs. Warren Burggren, Joseph Kunkel, Randall Phillis, and John Stoffolano. I also wish to thank Mrs. Elizabeth Brooks for secretarial assistance. Finally, thanks are due to Dr. D. Czeschlik and his staff at Springer Verlag for their patience and support. Amherst, MA, October 1991 M. S. KAULENAS V Contents Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Chapter 2 The Reproductive Elferent Duct Systems and Associated Structures. Development and Genetic Control of Differentiation . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 1 Origin of the Germ Cells and Associated Cells and Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 2 Differentiation of the Efferent Duct System and Associated Structures . . . . . . . . . . . . . . . . . . . 9 2. 2. 1 The Male System . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2. 2. 2 The Female System . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. 3 Genetic Control of Sexual Differentiation . . . . . 16 2. 3. 1 Daughterless. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. 3. 2 Sex Determination: Measurement of the X:A Ratio. . . . . . . . . . . . . . . . . . . . . . . . . . 20 2. 3. 3 Sex Lethal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2. 3. 4 Genes Controlling Somatic Sexual Differentiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2. 3. 5 Dosage Compensation . . . . . . . . . . . . . . . . . . . . . .
Book Synopsis Genes and Mechanisms in Vertebrate Sex Determination by : Gerd Scherer
Download or read book Genes and Mechanisms in Vertebrate Sex Determination written by Gerd Scherer and published by Birkhäuser. This book was released on 2013-04-17 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following an opening chapter by the late Susumu Ohno on paralogues of sex-determining genes, the five best-studied genes essential for early mammalian gonadal development are portrayed in detail: SF-1 and WT1 and their roles in early events in gonadal development, SRY and SOX9 in testis determination, and the anti-testis gene DAX-1. Subsequent chapters look at the roles of these genes in sex determination in marsupial mammals, birds, reptiles, amphibians and fish, and review the different sex-determining mechanisms, genetic and environmental, that operate in these different vertebrate classes. Two insights emerge: one, that the same basic set of genes appears to operate during early gonadal development in all vertebrates, despite the differences in mechanisms; the other, that sex determination in vertebrates results from a complex network of regulatory interactions and not from a simple hierarchical cascade of gene actions.
Book Synopsis Insect Hormones by : H. Frederik Nijhout
Download or read book Insect Hormones written by H. Frederik Nijhout and published by Princeton University Press. This book was released on 1998-02-22 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although insect endocrinology is one of the oldest and most active branches of insect physiology, its classic general texts are long out of date, while its abundant primary literature provides little biological context in which to make sense of the discipline as a whole. In this book, H. Frederik Nijhout's goal is to provide a complete, concise, and up-to-date source for students and nonspecialists seeking an overview of the dynamic and wide-ranging science that insect endocrinology has become since its beginnings nearly eighty years ago in the study of insect metamorphosis. The author offers a comprehensive survey of the many roles that hormones play in the biology of insects. Among the topics discussed are the control of molting, metamorphosis, reproduction, caste determination in social insects, diapause, migration, carbohydrate and lipid metabolism, diuresis, and behavior. The account features a summary of the most current and accurate thinking on the complex roles of ecdysone and juvenile hormone in the control of metamorphosis, a process still misunderstood and misrepresented in biological textbooks and many professional reviews. Throughout, the book's emphasis is on the biology of the organism and the ways in which physiological and developmental regulatory mechanisms are integrated into the insect's life cycle.
Book Synopsis Reproductive and Developmental Strategies by : Kazuya Kobayashi
Download or read book Reproductive and Developmental Strategies written by Kazuya Kobayashi and published by Springer. This book was released on 2018-06-01 with total page 783 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides new insights into the universality of biological systems in animal reproduction and development by a comparative study of a variety of mechanisms in animals ranging from basal invertebrates to vertebrates, including mammals. Animals accomplish genetic diversity through meiosis and fertilization, and during embryogenesis animals must produce specialized cell types, including germ cells, in accordance with their individual body plan. This series of phenomena is essential to the continuity of life in the animal kingdom, and animals show various reproductive and developmental strategies. This volume, comprising four parts, reviews animal kingdom diversity, including reproductive strategies and germ cell differentiation mechanisms (Part 1), sex determination and differentiation (Part2), the mechanisms of fertilization (Part 3), and body axis formation (Part 4). Readers will find descriptions of the reproduction or development of 180 species, 13 phyla, 35 classes, 74 orders, 117 families, and 151 genera in this book. Of particular interest is the diversity of molecules and mechanisms used to achieve the same biological purpose in different animals. Undergraduates, graduate students, and professional scientists who want a deeper understanding of animal reproductive and developmental mechanisms will find this book to be of great value.
Book Synopsis Sexual Biology and Reproduction in Crustaceans by : Thanumalaya Subramoniam
Download or read book Sexual Biology and Reproduction in Crustaceans written by Thanumalaya Subramoniam and published by Academic Press. This book was released on 2016-09-27 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sexual Biology and Reproduction in Crustaceans covers crustacean reproduction as it deals with the structural morphology of the gamete-producing primary sex organs, such as the testis and ovary, the formation and maturation of gametes, their fusion during fertilization, and embryonic development that lead to the release of larvae. Constituting a diverse assemblage of animals, crustaceans are best known by their common representatives, such as shrimps, lobsters, and crabs, but also include many more less familiar, but biologically important forms. This work covers the variety of ways in which both male and female gametes are produced by evolving different sexual systems in crustaceans, the range of reproductive systems, and the accordingly, and highly diverse, mechanistic modes of sex determination. In addition, the book features such topics as genetic and environmental determinants in sex determination pattern, variability of mechanisms of fertilization among different species, the origin of different mating systems, the associated mating and brooding behaviors, and the adaptive ability to different environmental conditions with discussion on the evolutionary ecology of social and sexual systems in certain species, which have shown eusocial tendencies, similar to social insects. Marine species occupying diversified ecological niches in tropical and temperate zones reproduce under definitive environmental conditions. Therefore, reproductive ecology of different crustaceans inhabiting different ecological niches also constitutes another important aspect of the work, along with yolk utilization and embryogenesis leading to release of different larval forms, which reflect on their aquatic adaptability. - Forms a valuable source of recent references on the current research in crustacean reproductive physiology - Covers various mating and breeding systems, providing illustrative examples for sexual selection, parental care of developing eggs and embryos, and the evolution of other reproductive behaviors - Features contributions written in the form of review articles, enabling readers to not only gain information in the respective subject, but also help them stimulate ideas in their chosen field of research - Includes a glossary created by the author to define technical terms - Demonstrates the ability of crustacean species to serve as useful model systems for other organisms, to investigate issues related to sexual conflict, mate choice, and sperm competition - Discusses techniques in endocrine research to help researchers in aquaculture develop protocols in the control of reproduction
Book Synopsis Function and Interaction of Sex Determination Genes in the Hemimetabolous Insect Oncopeltus Fasciatus by : Mara Laslo
Download or read book Function and Interaction of Sex Determination Genes in the Hemimetabolous Insect Oncopeltus Fasciatus written by Mara Laslo and published by . This book was released on 2013 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: The regulation and evolution of sex is a fundamental question in developmental biology. Sex determination mechanisms have only been studied in holometabolous insects, or insects with complete metamorphosis. In addition to being closely related to several human and agricultural pests, O. fasciatus is a member of the most closely related clade to these extensively studied holometabolous insects. Determining the genetic basis of sex in an outgroup such as O. fasciatus will shed light on how sex evolves. Candidate genes were chosen from the sex determination pathway of D. melanogaster. Transcript levels of transformer-2A, transformer-2B, intersex, and fruitless were examined at each developmental stage using quantitative PCR; a full list of significant pairwise comparisons is available in Supplementary Tables 1 and 2. Functional analyses of candidate genes virilizer, female-2-d, transformer-2, male-specific lethal-2, male-specific lethal-3, intersex , and fruitless were done using RNA interference methods. Results indicate that these sex determination genes play different roles in O. fasciatus compared to the established D. melanogaster model---most genes do not appear to have a role in sex determination. Additionally, although the genes fruitless and intersex are conserved, the phenotypes produced by the knockdown are non sex-specific. Interaction data suggests that fruitless promotes intersex expression---a novel interaction at the most downstream point of the sex determination pathway. These data support the theory that although upstream sex-determining genes vary widely across insect groups, downstream genes remain conserved.
Book Synopsis The Determination of Sex by : Leonard Doncaster
Download or read book The Determination of Sex written by Leonard Doncaster and published by . This book was released on 1914 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Biology of Reproduction by : Giuseppe Fusco
Download or read book The Biology of Reproduction written by Giuseppe Fusco and published by Cambridge University Press. This book was released on 2019-10-10 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: A look into the phenomena of sex and reproduction in all organisms, taking an innovative, unified and comprehensive approach.
Download or read book Sex Determination written by Guido Bacci and published by Pergamon. This book was released on 1965 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
