Development and application of gene mapping approaches, towards an integrated physical, radiation-hybrid and comparative map of dog chromosome five
thesisposted on 01.05.2014, 14:50 by Rachael Thomas
Efforts to generate a genome map for the domestic dog (Canis familiaris, CFA) have to date largely focussed on the isolation and characterisation of anonymous markers. This study was aimed at the development and application of techniques by which gene markers might be added to the map and integrated with data both from other approaches and from the genomes of other species. This is essential for the continuing use of the dog as a model system for the study of inherited traits. The generation of expressed sequence tags (partial cDNA sequences) was investigated as a route for achieving this aim. Seventeen of 76 cDNA clones analysed shared significant nucleotide similarity with previously annotated gene sequences from other species, forming a panel of resources for the extension of the existing dog gene map. Two gene markers were assigned to a specific dog chromosome by fluorescence in situ hybridisation. In a contrasting approach, reciprocal chromosome painting analysis was used to identify evolutionarily conserved chromosome segments (ECCS) between dog chromosome five (CFA 5) and human chromosomes 1, 11, 16 and 17. The boundaries between ECCS, and their relative orientation in the two genomes, were investigated by the assignment to CFA 5 of 12 genes selected from loci located at proximal and distal extremes of the corresponding human ECCS. Radiation hybrid mapping was performed for eleven gene markers and ten anonymous markers from CFA 5. One marker of each type was also analysed by meiotic linkage analysis. An integrated physical, radiation-hybrid and comparative map of CFA 5 is presented, and the relative merits of the mapping techniques investigated are discussed with reference to future prospects for the dog gene map.