Book Vol.2
Volume1 of the current series on Genome Dynamics and Stability identified Genome Integrity as the non plus ultra requirement for cellular life. Whether it is extracellular viral genomes, cellular prokaryotic or eukaryotic genomes, the integrity of genomes is the precondition for all life. This criterion is reflected in the underlying biochemical DNA/RNA metabolism processes,mainly represented by DNA/RNA replication/transcription and DNA repair. We now present the second book of this series. It deals with Recombination and Meiosis: Crossing-Over and Disjunction. It will soon be accompanied by a third book, likewise dealing with recombination and meiosis, but focusing a little more on theory–practice coupled approaches. The title of the third book will be: Recombination and Meiosis: Models,Means and Evolution. When cells, during evolution, assembled into multi- cellular aggregates – a phenomenon we have to accept as a fact of complex life that has happened more than once – many of the most basic genome-maintenance factors were reshaped by Darwinian selectional forces. To be sure, long before the emergence of multicellular organisms, cyclic mechanisms became established to combine two haploid genomes and to reduce the diploid genome back to haploid ones. Yet, the relative abundance of haploid versus diploid stages remained highly variable. After billions of years of unicellular evolution, within a lineage stemming froma diploid protist with gametic meiosis, the origin of modern metazoans began in a (pre)cambrian diversification (i.e.explosion) to multicellular diversity where selectional forces always had a broad spectrum of molecular factors, phenomena and mechanisms to act upon. Among the molecular and cellular key processes making multicellular complexity possible were i) the potentially immortal germline from which somatic cells differentiate and ii) meiosis to precisely half the number of chromosomes established in the zygote. The differentiation of gametes into resourceful, immobile eggs and highly motile sperm cells probably developed very early in the metazoan lineage. In a certain, evolutionarily meaningful, way the animal body can be considered the germ cells’ most successful means of being nourished and disseminated. As a cytogenetic phenomenon preceding gametogenesis, where homologous chromosomes undergo programmed crossing over and recombination, meiosis has been known since the early days of the chromosome theory of inheritance, but only more recently have the underlying molecular processes become accessible. The present book focuses on crossing over between and disjunction of chromosomesduring themeiotic cell cycle. The first chapter is an introductory overview written by Richard Egel, the initiator of this twin-volume edition; this synopsis covers the scope of both accompanying books. The second chapter by Jos´e Suja and Julio Rufas deals with the highly condensed cores of mitotic and meiotic chromosomes, their supramolecular structures and the involved segregation processes. Written by these leading specialists on visualizing the core structures by silver staining, it presents the current view on the relationship between the chromatid cores and the synaptonemal complex lateral elements, DNA topoisomerase IIα, and the glue between individual chromosomes, i.e. condensin and cohesin complexes, is assessed. The third chapter is written by Koichi Tanaka andYoshinori Watanabe. It represents pioneering work in unraveling the molecular systems of chromatid cohesion. We are here confronted with key questions as to how mono-oriented sister kinetochores attach to microtubules, each to only one cellularpole, and how sisterchromatids separate during meiosis I, while homologs remain paired until their segregation in meiosis II. The centrally important key proteins are presented. The fourth chapter is written by another pioneer, Scott Keeney, who discovered the DNA double-strand break (DSB) initiating Spo11 protein in yeast and the mechanism involved in how chromosomes initiate programmed recombination during meiosis by means of this archaeal-like topoisomerase. The fifth chapter by Sonam Mehrotra, Scott Hawley and Kim McKim deals with Drosophila as ametazoan model organism providing molecular, genetic and cytological details on how meiotic pairing and synapsis can proceed independently of programmed DSBs in DNA.Further, it elucidates the relationship of DSB formation to synapsis,how crossovers are determined and formed, and the role of chromosome structure in regulating DSB formation and repair, including specialized pairing sites. The chapter by Terry Ashley deals with recombination nodules in mammalian meiotic chromosomes and the dynamics of shifting protein compositions, while cytological structures remain nearly constant. The seventh chapter by Celia May, Tim Slingsby and Sir Alec Jeffreys exploits the human HapMap project to shed light on recombinational hotspots in human chromosomes during meiosis. The eighth chapter by Haris Kokotas, Maria Grigoriadou and Michael Petersen reviews our current understanding of human chromosomal abnormalities, as caused by meiotic nondisjuction, using Trisomy21 as a case study. While metazoans dominate the chapters sofar–with some recourse to yeasts – plants represent another multicellular kingdom of life. In the ninth chapter Gareth Jones and Chris Franklin focus on botany’s most prominent modelsystem, i.e. Arabidopsis thaliana. It reviews meiotic recombination, chromosome organization and progression in this model plant, which of course, stands in for the key role of plants in agricultural production. Finally, Livia P´erez-Hidalgo, Sergio Moreno and Christina Martin-Castellanos link the meiotic program to modified aspects of mitotic cellcycle control. Itreviews how mitotic regulators adapt or are co-opted to the functional necessities of the meiotic program, paying particular attention to meiosis-specific factors whose functions are essential for meiosis. This comparative review is rooted in the pioneering cell-cycle studies on baker’s yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe), from where it extends to mammalian gametogenesis and other multicellular eukaryotes. A similar range of model studies has also applied to the scope of the chapter by Tanaka and Watanabe and the review of Scott Keeney. Following the contents table of this book, the list of forthcoming chapter titles in the accompanying volume is included in advance. In fact, as some of the individual chapters had been published online first, before the editorial decision to divide the printed edition into two books was taken, the preliminary cross-references had not yet accounted for the split. We apologize for any inconvenience this may cause, but the listing of all the chapter titles in both books should hopefully direct the reader to the proper destination. We would also like to point out that the missing chapter numbers are not neglect but reflect an obligatory compromise necessitated by publishing all the manuscripts OnlineFirst immediately after they have been peer reviewed, revised,accepted and copy edited (see, www.springerlink.com/content/119766/). We most cordially thank all the chapter authors for contributing to this topical edition of two accompanying books. Without their expertise and dedicated work this comprehensive treatise would not have been possible. Receiving the incoming drafts as editors, we had the great privilege of being the first to read so many up-to-date reviews on the various aspects of meiotic recombination and model studies elucidating this ever-captivating field. Also, we greatly appreciate the productive input of numerous referees, who have assisted us in striving for the highest level of expertship, comprehensiveness and readability. We are also deeply indebted to the Springer and copy-editing staff. In particular, we would like to mention Sabine Schreck, the editor at Springer Life Sciences (Heidelberg), Ursula Gramm, the desk editor (Springer, Heidelberg) MartinWeissgerber, the productioneditor (LE-TeXGBR, Leipzig)
Book Vol.2
Volume1 of the current series on Genome Dynamics and Stability identified Genome Integrity as the non plus ultra requirement for cellular life. Whether it is extracellular viral genomes, cellular prokaryotic or eukaryotic genomes, the integrity of genomes is the precondition for all life. This criterion is reflected in the underlying biochemical DNA/RNA metabolism processes,mainly represented by DNA/RNA replication/transcription and DNA repair. We now present the second book of this series. It deals with Recombination and Meiosis: Crossing-Over and Disjunction. It will soon be accompanied by a third book, likewise dealing with recombination and meiosis, but focusing a little more on theory–practice coupled approaches. The title of the third book will be: Recombination and Meiosis: Models,Means and Evolution. When cells, during evolution, assembled into multi- cellular aggregates – a phenomenon we have to accept as a fact of complex life that has happened more than once – many of the most basic genome-maintenance factors were reshaped by Darwinian selectional forces. To be sure, long before the emergence of multicellular organisms, cyclic mechanisms became established to combine two haploid genomes and to reduce the diploid genome back to haploid ones. Yet, the relative abundance of haploid versus diploid stages remained highly variable. After billions of years of unicellular evolution, within a lineage stemming froma diploid protist with gametic meiosis, the origin of modern metazoans began in a (pre)cambrian diversification (i.e.explosion) to multicellular diversity where selectional forces always had a broad spectrum of molecular factors, phenomena and mechanisms to act upon. Among the molecular and cellular key processes making multicellular complexity possible were i) the potentially immortal germline from which somatic cells differentiate and ii) meiosis to precisely half the number of chromosomes established in the zygote. The differentiation of gametes into resourceful, immobile eggs and highly motile sperm cells probably developed very early in the metazoan lineage. In a certain, evolutionarily meaningful, way the animal body can be considered the germ cells’ most successful means of being nourished and disseminated. As a cytogenetic phenomenon preceding gametogenesis, where homologous chromosomes undergo programmed crossing over and recombination, meiosis has been known since the early days of the chromosome theory of inheritance, but only more recently have the underlying molecular processes become accessible. The present book focuses on crossing over between and disjunction of chromosomesduring themeiotic cell cycle. The first chapter is an introductory overview written by Richard Egel, the initiator of this twin-volume edition; this synopsis covers the scope of both accompanying books. The second chapter by Jos´e Suja and Julio Rufas deals with the highly condensed cores of mitotic and meiotic chromosomes, their supramolecular structures and the involved segregation processes. Written by these leading specialists on visualizing the core structures by silver staining, it presents the current view on the relationship between the chromatid cores and the synaptonemal complex lateral elements, DNA topoisomerase IIα, and the glue between individual chromosomes, i.e. condensin and cohesin complexes, is assessed. The third chapter is written by Koichi Tanaka andYoshinori Watanabe. It represents pioneering work in unraveling the molecular systems of chromatid cohesion. We are here confronted with key questions as to how mono-oriented sister kinetochores attach to microtubules, each to only one cellularpole, and how sisterchromatids separate during meiosis I, while homologs remain paired until their segregation in meiosis II. The centrally important key proteins are presented. The fourth chapter is written by another pioneer, Scott Keeney, who discovered the DNA double-strand break (DSB) initiating Spo11 protein in yeast and the mechanism involved in how chromosomes initiate programmed recombination during meiosis by means of this archaeal-like topoisomerase. The fifth chapter by Sonam Mehrotra, Scott Hawley and Kim McKim deals with Drosophila as ametazoan model organism providing molecular, genetic and cytological details on how meiotic pairing and synapsis can proceed independently of programmed DSBs in DNA.Further, it elucidates the relationship of DSB formation to synapsis,how crossovers are determined and formed, and the role of chromosome structure in regulating DSB formation and repair, including specialized pairing sites. The chapter by Terry Ashley deals with recombination nodules in mammalian meiotic chromosomes and the dynamics of shifting protein compositions, while cytological structures remain nearly constant. The seventh chapter by Celia May, Tim Slingsby and Sir Alec Jeffreys exploits the human HapMap project to shed light on recombinational hotspots in human chromosomes during meiosis. The eighth chapter by Haris Kokotas, Maria Grigoriadou and Michael Petersen reviews our current understanding of human chromosomal abnormalities, as caused by meiotic nondisjuction, using Trisomy21 as a case study. While metazoans dominate the chapters sofar–with some recourse to yeasts – plants represent another multicellular kingdom of life. In the ninth chapter Gareth Jones and Chris Franklin focus on botany’s most prominent modelsystem, i.e. Arabidopsis thaliana. It reviews meiotic recombination, chromosome organization and progression in this model plant, which of course, stands in for the key role of plants in agricultural production. Finally, Livia P´erez-Hidalgo, Sergio Moreno and Christina Martin-Castellanos link the meiotic program to modified aspects of mitotic cellcycle control. Itreviews how mitotic regulators adapt or are co-opted to the functional necessities of the meiotic program, paying particular attention to meiosis-specific factors whose functions are essential for meiosis. This comparative review is rooted in the pioneering cell-cycle studies on baker’s yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe), from where it extends to mammalian gametogenesis and other multicellular eukaryotes. A similar range of model studies has also applied to the scope of the chapter by Tanaka and Watanabe and the review of Scott Keeney. Following the contents table of this book, the list of forthcoming chapter titles in the accompanying volume is included in advance. In fact, as some of the individual chapters had been published online first, before the editorial decision to divide the printed edition into two books was taken, the preliminary cross-references had not yet accounted for the split. We apologize for any inconvenience this may cause, but the listing of all the chapter titles in both books should hopefully direct the reader to the proper destination. We would also like to point out that the missing chapter numbers are not neglect but reflect an obligatory compromise necessitated by publishing all the manuscripts OnlineFirst immediately after they have been peer reviewed, revised,accepted and copy edited (see, www.springerlink.com/content/119766/). We most cordially thank all the chapter authors for contributing to this topical edition of two accompanying books. Without their expertise and dedicated work this comprehensive treatise would not have been possible. Receiving the incoming drafts as editors, we had the great privilege of being the first to read so many up-to-date reviews on the various aspects of meiotic recombination and model studies elucidating this ever-captivating field. Also, we greatly appreciate the productive input of numerous referees, who have assisted us in striving for the highest level of expertship, comprehensiveness and readability. We are also deeply indebted to the Springer and copy-editing staff. In particular, we would like to mention Sabine Schreck, the editor at Springer Life Sciences (Heidelberg), Ursula Gramm, the desk editor (Springer, Heidelberg) MartinWeissgerber, the productioneditor (LE-TeXGBR, Leipzig)