This study reports upon the investigation of a number of genetic polymorphisms in indigenous population samples of three regions of the British Isles: the Isle of Man, Cumbria and South West Scotland. Sample selection proved to be important because differences were found in the similarly selected indigenous Manx population - between donors and non-donors. In addition to a study of phenotype distributions and gene frequencies in the three selected populations, a regional analysis of the Manx data, though on a limited level, was effected. Though great difficulties were encountered obtaining indigenous samples, comparisons were performed between the Manx and population samples from selected regions of the mainland of the British Isles as well as certain north-west European populations. Possible explanations of the differences observed between the Manx and surrounding populations were proposed, but it was also suggested that an analysis of the demographic data would be most informative.