Download or read book Control of Interactions Between Homologous Chromosomes During Meiosis written by Neeraj Joshi and published by . This book was released on 2014 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: In sexually reproducing organisms, haploid gametes arise from diploid germ cells through the specialized cell division of meiosis. Unique features of meiosis include programmed double strand break (DSB) formation, preferential DSB repair with the homologous chromosome (homolog), synapsis and crossover (CO) formation. Without COs, homologs mis-segregate, resulting in aneuploid gametes which exhibit a chromosome surplus or deficit. Aneuploidy is often associated with birth defects and cancer. Here, I have used budding yeast as a model organism to investigate: (i) how recombination at the DNA level is linked to transitions in chromosome structure, (ii) how preferential use of the homolog versus the sister chromatid for repair of meiotic DSBs is established, and (iii) how global DSB levels affect meiotic cell cycle progression. I have also developed the Homolog Pairing Capture (HPC) assay, a novel method for identifying pairing regions between homologous chromosomes. My work demonstrates that the meiosis-specific AAA ATPase Pch2 links chromosome morphogenesis with recombination at the DNA level thereby shaping the genome-wide recombination landscape (Joshi et al. 2009). I have discovered that two meiotic DSBs subsets, "earlier, low abundance" and "later, high abundance" DSBs exhibit distinct features (Joshi and Börner, submitted). Early, low level DSBs lack homolog bias. Their repair is controlled by universally conserved checkpoint kinase Tel1/ATM as well as by meiosis-specific checkpoint ATPase Pch2. Processing of "later, high abundance" DSBs is primarily controlled by checkpoint kinase Mec1/ATR. These findings identify unique roles for presumed checkpoint factors in wild-type meiosis. I have further discovered a role of nucleus-wide abundance of DSBs in activation of the meiotic recombination checkpoint. Shared features of normal meiosis at elevated temperatures and defective meiosis identifies novel roles of the recombination checkpoint during wild-type meiosis. Together, these findings suggest that meiotic checkpoint components orchestrate events at three levels, namely, chromosome structure, DNA recombination, and cell-cycle progression, thereby ensuring accurate segregation of homologous chromosomes.
Download or read book Plant Meiosis written by Wojtek Pawlowski and published by Humana Press. This book was released on 2013-04-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meiosis is one of the most critical processes in eukaryotes, required for continuation of species and generation of new variation. In plants, meiotic recombination is by far the most important source of genetic variation. In Plant Meiosis: Methods and Protocols, expert researchers in the field detail methods for molecular cytogenetics and chromosome analysis in plants. These state-of -the-art protocols allow studying the organization and behavior of the genetic material in a wide range of both model and crop species. Written in the highly successful Methods in Molecular BiologyTMseries format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step and readily reproducible laboratory protocols, and key tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Plant Meiosis: Methods and Protocols provides and extensive list of protocols developed and used in a number of laboratories at the cutting edge of meiosis and chromosome research.
Download or read book Regulation of Crossing over During Meiosis written by Yi-Hwa Hwang and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During meiosis, parental chromosomes (homologs) pair and undergo crossover recombination. Crossovers are physical connections between the homologs, which are required for their proper segregation. The frequency of homologs that lack a crossover is very rare, indicating a highly regulated process, but small chromosomes are more likely to lack a crossover. To better understand crossover control and the problems encountered by small chromosomes, I studied meiotic recombination between artificially shortened chromosomes in budding yeast. I have found that on average small chromosomes undergo a higher rate of crossing-over than do large chromosomes due to enhanced bias of recombination to occur between homologs instead of sister chromatids. This effect is exaggerated in a mutant that is defective for telomere-led, actin-dependent chromosome movement. Despite an overall increase in the average crossover rate, small chromosomes completely fail to crossover in ~10% of meioses and are consequently prone to missegregate at the first division. This class of cells shows a general decrease in recombination between the short chromosomes consistent with defective pairing. I also demonstrated that short chromosomes are less efficient at converting recombinational interactions into crossovers than their native counterparts. To reconcile these data I propose that stable homolog synapsis is an essential determinant of efficient crossover assurance that requires multiple stabilized recombinational interactions - a condition that is harder for small chromosomes to achieve. I also discuss how delayed pairing and synapsis of small chromosomes could enhance interhomolog bias via enhanced checkpoint signaling.
Download or read book DNA Methylation in Plants written by B. F. Vani︠u︡shin and published by Nova Science Publishers. This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A high degree of nuclear DNA (nDNA) methylation is a specific feature of plant genomes, they do contain 5-methylcytosine (m5C) and N6-methyladenine (m6A). More than 30% m5C is located in CNG sequences. Specific changes in DNA methylation accompany the entire life of a plant starting from seed germination up to the death programmed or induced by various agents and factors of biological or abiotic nature. Modulation of DNA methylation is one of the possible modes of the hormonal action in plant. DNA methylation in plants is species-, tissue-, organelle- and age-specific; it is involved in the control of all genetic functions including transcription, replication, DNA repair, gene transposition and cell differentiation. DNA methylation is engaged in gene silencing and parental imprinting, it controls transgenes and foreign DNA. Plants have much more complicated and sophisticated system of the multi-component and sometimes even conjugated genome (nuclear DNA) methylations compared with animals; besides, unlike animals, they have the plastids with their own unique DNA modification system that may control plastid differentiation and functioning; DNA methylation in plant mitochondria is performed in other fashion compared with it in nuclei. The nuclear DNA methylation system is controlled by three major families of cytosine DNA-methyltransferase genes, at least. In contrast to animals the inactivation of major maintenance methyltransferase MET1 (similar to animal Dnmt1) has no significant consequences for plant survival. Other plant cytosine DNA-methyltransferases have no analogs in animals. Some of them (DRM) are responsible for de novo DNA methylation including asymmetric sequences. Plant gene may be methylated at both adenine and cytosine residues; specific adenine DNA-methyltransferase was described. Adenine DNA methylation may influence cytosine modification and vice versa. Anyway, two different systems of the genome modification based on methylation of adenines and cytosines coexist in higher plants. The specific endonucleases discriminating between methylated and unmethylated DNA are present in plants. Thus, plants may have restriction-modification system. There are peculiar complicated controls for growth and development by DNA methylations in plants; they are well co-ordinated with other epigenetic signals modulating chromatin organisation.
Download or read book The Role of the Pairing Center and Its Interaction with the Nuclear Envelope During Meiosis in C Elegans written by Aya Sato and published by . This book was released on 2010 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sexual reproduction requires meiosis, the unique cell division in which haploid gametes are generated from a diploid cell. A hallmark of meiotic prophase is the formation of pairwise linkages between homologous chromosomes, which later enable them to segregate away from each other at meiosis I. In most organisms the pairing of homologous chromosomes is reinforced by polymerization of the synaptonemal complex (SC) between paired chromosome axes, or synapsis. The primary questions addressed in this study are: 1) how pairing is accomplished and 2) how synapsis is regulated so that it occurs selectively between homologs. In Chapter I, I present evidence that a bridge of the nuclear envelope proteins comprised of SUN-1 and ZYG-12 connects meiotic chromosomes to the microtubule cytoskeleton, and this connection spanning the nuclear envelope is critical for coordinating homolog pairing and synapsis. I propose a model in which dynein-based forces are used to assess homology between chromosomes and to license subsequent chromosome interactions during meiotic prophase. In Chapter 2, I identify a novel Pairing Center-interacting protein DPY-30 and present my characterization of the germline in a dpy-30 mutant. I explore different possibilities to investigate the functional significance of the interaction between DPY-30 and Pairing Center proteins. I discuss possible roles of DPY-30 in early meiosis based on my preliminary results.
Download or read book Molecular Genetics of Recombination written by Andrés Aguilera and published by Springer Science & Business Media. This book was released on 2007-04-24 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work offers a fascinating insight into a crucial genetic process. Recombination is, quite simply, one of the most important topics in contemporary biology. This book is a totally comprehensive treatment of the subject, summarizing all existing views on the topic and at the same time putting them into context. It provides in-depth and up-to-date analysis of the chapter topics, and has been written by international experts in the field.
Download or read book Handbook of Maize written by Jeff L. Bennetzen and published by Springer Science & Business Media. This book was released on 2009-01-16 with total page 785 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize is one of the world’s highest value crops, with a multibillion dollar annual contribution to agriculture. The great adaptability and high yields available for maize as a food, feed and forage crop have led to its current production on over 140 million hectares worldwide, with acreage continuing to grow at the expense of other crops. In terms of tons of cereal grain produced worldwide, maize has been number one for many years. Moreover, maize is expanding its contribution to non-food uses, including as a major source of ethanol as a fuel additive or fuel alternative in the US. In addition, maize has been at the center of the transgenic plant controversy, serving as the first food crop with released transgenic varieties. By 2008, maize will have its genome sequence released, providing the sequence of the first average-size plant genome (the four plant genomes that are now sequenced come from unusually tiny genomes) and of the most complex genome sequenced from any organism. Among plant science researchers, maize has the second largest and most productive research community, trailing only the Arabidopsis community in scale and significance. At the applied research and commercial improvement levels, maize has no peers in agriculture, and consists of thousands of contributors worthwhile. A comprehensive book on the biology of maize has not been published. The "Handbook of Maize: the Genetics and Genomics" center on the past, present and future of maize as a model for plant science research and crop improvement. The books include brief, focused chapters from the foremost maize experts and feature a succinct collection of informative images representing the maize germplasm collection.
Download or read book Stem Cells in Reproductive Medicine written by Carlos Simón and published by Cambridge University Press. This book was released on 2013-07-04 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem cell science has the potential to impact human reproductive medicine significantly - cutting edge technologies allow the production and regeneration of viable gametes from human stem cells offering potential to preciously infertile patients. Written by leading experts in the field Stem Cells in Reproductive Medicine brings together chapters on the genetics and epigenetics of both the male and female gametes as well as advice on the production and regeneration of gene cells in men and women, trophoblasts and endometrium from human embryonic and adult stem cells. Although focussing mainly on the practical elements of the use of stem cells in reproductive medicine, the book also contains a section on new developments in stem cell research. The book is essential reading for reproductive medicine clinicians, gynecologists and embryologists who want to keep abreast of practical developments in this rapidly developing field.
Download or read book Principles of Biology written by Lisa Bartee and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Principles of Biology sequence (BI 211, 212 and 213) introduces biology as a scientific discipline for students planning to major in biology and other science disciplines. Laboratories and classroom activities introduce techniques used to study biological processes and provide opportunities for students to develop their ability to conduct research.
Download or read book Genetics for Surgeons written by Patrick John Morrison and published by Remedica. This book was released on 2005 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Morrison (human genetics, University of Ulster, UK) and Spence (biomedical science, University of Ulster, UK) offer an accessible reference on the genetic disorders that surgeons can expect to meet in general surgical practice. Written in non-technical language, with a glossary, list of abbreviations, and color and b&w photos and medical images, the book supplies an introduction to the nomenclature and technology of molecular biology, and will be a useful starting point for those who wish to extend their knowledge. Annotation :2005 Book News, Inc., Portland, OR (booknews.com).
Download or read book Molecular Biology of the Cell written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chromosome Biology written by Rudi Appels and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chromosome biology has been brought to a golden age by phenomenal advanced in molecular genetics and techniques. This is true in the plant arena, and it is becoming increasingly true in animal studies, where chromosomes are more difficult to work with. With advanced knowledge of transformation, scientists can tell exactly where a new element enters a chromosome. Conversely, molecular biologists can make large mistakes if they do not understand the behavior of chromosomes. Written by internationally recognized experts in the field, this book is the most authoritative work on the subject to date. Students of genetics, crop science and plant breeding, entomology, animal science, and related fields will benefit from this comprehensive and practical textbook.
Download or read book Biology for AP Courses written by Julianne Zedalis and published by . This book was released on 2017-10-16 with total page 1923 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biology for AP® courses covers the scope and sequence requirements of a typical two-semester Advanced Placement® biology course. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology for AP® Courses was designed to meet and exceed the requirements of the College Board’s AP® Biology framework while allowing significant flexibility for instructors. Each section of the book includes an introduction based on the AP® curriculum and includes rich features that engage students in scientific practice and AP® test preparation; it also highlights careers and research opportunities in biological sciences.
Download or read book The Cell in Development and Inheritance written by Edmund Beecher Wilson and published by . This book was released on 1896 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Textbook of Human Reproductive Genetics written by Karen Sermon and published by Cambridge University Press. This book was released on 2014-04-10 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together genetics, reproductive biology and medicine for an integrative view of the emerging specialism of reproductive genetics.
Download or read book Meiosis and Gametogenesis written by and published by Academic Press. This book was released on 1997-11-24 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: In spite of the fact that the process of meiosis is fundamental to inheritance, surprisingly little is understood about how it actually occurs. There has recently been a flurry of research activity in this area and this volume summarizes the advances coming from this work. All authors are recognized and respected research scientists at the forefront of research in meiosis. Of particular interest is the emphasis in this volume on meiosis in the context of gametogenesis in higher eukaryotic organisms, backed up by chapters on meiotic mechanisms in other model organisms. The focus is on modern molecular and cytological techniques and how these have elucidated fundamental mechanisms of meiosis. Authors provide easy access to the literature for those who want to pursue topics in greater depth, but reviews are comprehensive so that this book may become a standard reference.Key Features* Comprehensive reviews that, taken together, provide up-to-date coverage of a rapidly moving field* Features new and unpublished information* Integrates research in diverse organisms to present an overview of common threads in mechanisms of meiosis* Includes thoughtful consideration of areas for future investigation
Download or read book The Kinetochore written by Peter De Wulf and published by Springer Science & Business Media. This book was released on 2008-12-16 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: Kinetochores orchestrate the faithful transmission of chromosomes from one generation to the next. Kinetochores were first depicted over 100 years ago, but kinetochore research has progressed by leaps and bounds since the first description of their constituent DNA and proteins in the 1980s. “The Kinetochore: from Molecular Discoveries to Cancer Therapy” presents a thorough up-to-date analysis of kinetochore and centromere composition, formation, regulation, and activity, both in mitosis and meiosis, in humans and “model” eukaryotic species, and at natural and mutant neocentromeres. Recently initiated translational research on kinetochores is also discussed as kinetochores are being mined as a very rich target for the next generations of anti-cancer drugs.
