Cytogenetic studies of Pseudobarbus and selected Barbus (Pisces: Cyprinidae) of southern Africa

The aim of this study was to explore the karyology of temperate southern African barbine species in order to determine the extent and significance of polyploidy within the species. The study presents an optimised in vivo karyological protocol for the small barbines. The analysis of chromosomal data was explored using two approaches; measured (quantitative) and visual (qualitative). The karyology of 16 species of Barbus and six species of Pseudobarbus (Pisces: Cyprinidae) is reported. The study represents an almost complete (22/23 species) karyological survey of the temperate barbines. Chromosome number, arm numbers (NF) are recorded and karyotype morphology described for all species. Nucleolar organiser regions (NOR)s of 18 species have been examined by silver staining. Seven different AgNOR phenotypes occur among the species examined. Chromosome complements of the different species indicate at least three ploidy levels; diploid, tetraploid and hexaploid. Higher ploidy levels are represented in 78% (18/23) of species within the temperate fauna. This finding is remarkable, in the light of global proportions of cyprinid karyotypes, and provides an opportunity to shed further light on the evolution of polyploidy in barbine cyprinids. Results show that morphologically defined species complexes have distinct karyotypes, and most probably form cohesive phyletic clades. A phylogenetic tree was constructed using traditional morphological characters and tested against karyological data. The results suggests that similar ploidy states do not necessarily indicate close relationship between species. This supports a hypothesis of polyphyly for the African barbine cyprinids and also provides independent support for species complexes such as the "chubbyhead barb group" and the Pseudobarbus lineage. The broader implications of karyological findings are discussed within the context of African barbines and recommendations for further cytogenetic research are provided

Quest Volume 6 Number 1

Maths, engineering and soccer stadiums; Why do you need to understand maths and science to build soccer stadia? An examination of the way in which geometry, trigonometry and mathematics are used in the building of these wonderful structures; Getting to the match: Transport is not something that you usually associate with science, but there is a lot of careful analysis used in working out the best way to transport large numbers of people; Sustainability - the key to the future of our soccer stadia: QUEST spoke to the experts who are making sure that the money spent on building our soccer stadia is being used wisely; The mathematics of soccer: How mathematics and statistics can be used to go some way towards answering the question, 'will my team win?'; Kicking a soccer ball QUEST shows you the anatomy behind that vital kick; Earth explorers: The Earth explorer satellites promise to revolutionise our understanding of the world around us; Restoration in South Africa - a case study; Ecological restoration is one approach to saving our changing landscape; Understanding the ocean floor: Seamount ecosystems are crucial to our understanding of the ocean floor; A life on the ocean wave: Riaan describes the excitement of working with global experts on oceanography; The birth of a fish: The fascinating journey from egg to larva; Mercury exposure - are we at risk?: Mercury is more a part of our everyday environment than you might realise;Academy of Science of South Africa: Department of Science and Innovatio