Browsing by Author "Rege, J.E.O."
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Item Genetic Diversity and Relationship of Indigenous Kenyan Camel Breeds : Preliminary Results(Animal Production Society of Kenya, 2001) Mburu, D.N.; Ochieng, J.W.; Jianlin, H.; Kaufmann, B.; Kuria, S.G.; Rege, J.E.O.; Hanotte, O.H.; International Livestock Research Institute, Kenya; State Key Laboratory of Arid Agroecology; University of Hohenheim; Kenya Agricultural Research Institute; International Livestock Research Institute, EthiopiaCamels are important resource for the desert-dwelling communities. They are a source of income, milk and meat and often play an important sociocultural role in pastoralist societies. In order to help formulate a rational conservation, utilisation and Development policy for the species in Kenya, a diversity of Kenyan camel breeds is being studied using microsatellite markers. Preliminary results on the analyses of four breeds (Rendille, Gabra, Turkana and Somali) with 10 micro\92satellite loci are Reported here. Their relationships with dromedary and bactrian populations from the Arabian Peninsula and the Asian continent have been investigated. Genetic distances between Kenyan camel populations are low with the Rendille and Gabra camels being the most closely related breeds. Kenyan camels are genetically clearly distinct from the Asian and Arabian dromedary as well as from the bactrian camel. They are genetically less variable than non-Kenyan populations, possibly due to a lower number of initial individuals.Item A Monte Carlo Analysis of Some Alternative Estimators of Family Genotypic Values(1990) Rege, J.E.O.; Department of Animal Production, University of Nairobi, P.O. Box 29053, Nairobi, KenyaThe selection problem in most animal breeding situations is the identification of replacement animals from a population composed of half-sibs, full-sibs or (as in pigs) litters. Often, any one population is composed of a mixture of these relationships pd, depending on the mating system practised and the population (or herd) size, a wide spectrum of relationships can be found. Information from such situations can best be in one of three ways, namely: selection entirely on family basis, saving only the animals from the best families (based on some measureh,. selection based entirely on individual performance saving only the best individuals regardless-of the performance of others in the family; or selection on some basis which combines emphasis on both the individual performance and the overall family performance. Broadly, the first alternative falls under family selecticd, the second under mass (or truncation) selection while the third is the subject of index selection. In mass selection the observation on the individual (candidate) forms the basis for selection. Family and index selection, however, involve computation of single values from individual observations. Strictly, family selection, in whatever form, is simply a special case of index selection in which either each family (or genetic group) gets its own index value which is then used to rank them or ranking is based on an index value computed for each individual within a family using the individual's own observation and some function of the overall family performance. The objective of this study was to investigate, using a Monte Carlo simulation, properties of three measures (or estimators) which can be used to rank genetic groups (or families), viz. simple average of genetic groups; average of genetic groups transformed to unbias the variance, and selection index derived from a one-way (genetic group) model.
