ANALYSIS OF THE EVOLUTION AND GENETIC DIVERSITY WITHIN AND BETWEEN BALEARIC AND IBERIAN CAT POPULATIONS

A study of genic diversity and spatial autocorrelation of some cat pop ulations has been carried out at the microgeographic (cities of Palma Majorca and Ibiza) and the macrogeographic (Balearic Islands and total Spain) levels. In both cases, the cat populations show high levels of gene flow (Nm) and few stochastic effects (e.g., genetic drift). Thus , cat populations are closer to the viewpoint of Mayr (1954)-that is, a species composed of large effective populations very near to panmixi a-than to the hypothesis of demic structuration with very little gene flow between populations. The genetic differentiation between cat popu lations seems to be lower than that found in other vertebrate species. Nevertheless, I have found the existence of significant genetic heter ogeneity at both the micro- and macrogeographical levels. At the micro geographical level, the differences in genetic heterogeneity at each o f the loci studied within two populations could be caused by the intro duction of the diverse mutant alleles into the analyzed populations at different historical times. At the macrogeographical level, the inter action of a strong differential gene flow caused by historical factors (and demographic changes) and, perhaps, natural selection for some lo ci is a possible explanation. The cat population data are in agreement with the hypothesis of Schwartz and Armitage (1 980), who argued that social structures promote and augment gene flow between groups or pop ulations of the same species. Humans seem to be the dominant element t hat explains the observed high rates of gene flow between cat populati ons.