Induced diploid gynogenesis and polyploidy in the ornamental (koi) carp Cyprinus carpio L.
The results of a series of experiments conducted in our laboratory on the ornamental common carp (koi), aimed at optimizing heat-shock chromosome-set manipulation procedures, are described. The timing of heat-shock initiation was expressed in the relative unit of embryological age (τ0) in order to standardize this parameter, the absolute time for heat-shock initiation being calculated from duration of one τ0 at two different pre-treatment water temperatures. Heat shocks were applied within the periods of 0.05–0.60 τ0 and 1.20–2.20 τ0 which, respectively, cover the successive phases of the 2nd meiotic division and the 1st cleavage. The highest production of diploid gynogenetic offspring was observed when heat shocks were initiated at 0.15–0.25 τ0 and at 1.5 τ0, after insemination, corresponding to anaphase of meiosis-II, and metaphase of the 1st cleavage, respectively. Similar results were obtained irrespective of the different pre-treatment water temperatures, thus confirming the possibility of standardizing heat-shock timing by τ0.
Androgenesis, gynogenesis and the production of clones in fishes: A review
Fish species that have external fertilization can be reproduced by induced parthenogenesis. The nuclear content of either the sperm or egg is destroyed by UV or gamma irradiation, and the treated gamete then is fused with an untreated egg or sperm to form a haploid embryo. This is subsequently made diploid by inhibition of either the second meiotic division or the first cell division. After first cell division blockage, the resulting individual is a so-called doubled haploid (DH). DH individuals carry only the duplicated set of chromosomes inherited from the untreated egg or sperm and are, by definition, fully homozygous. In the first part of this review, we discuss the latest insights into the mechanisms underlying the process of making meiotic diploids and DH individuals, and review the problems associated with making and characteristics of doubled haploids and clones in fishes. In the second part of this review, we explore the use of doubled haploids and clones in quantitative trait locus mapping and selective breeding.
Barbarians, Gentlemen and Players : A Sociological Study of the Development of Rugby Football
Part I: Folk Antecedents and Transitional Forms of Football in the Public Schools 1. The folk antecedents of modern rugby and their decline 2. Football in the early 19th century public schools Part II: The Modernisation of Rugby Football 3. The preconditions for modernization: embourgeoisement and public school reform 4. The incipient modernization of rugby football 5. The 'civilising process' and the formation of the RFU. 6. The democratization of rugby football. 7. Professionalisation and the amateur response. 8. The split. 9. The class structure and the professionalisation of British sport. Part III: The Development of Rugby Football as a Modern Sport 10. The professionalisation of rugby league. 11. Rugby union as a modern sport: bureaucracy, gate-taking clubs and the swansong of amateurism. Conclusion: Sociological Reflections on the Crisis in Modern Sport