FINE-STRUCTURE OF GENE-FREQUENCY LANDSCAPES IN DOMESTIC CAT - THE OLDAND NEW WORLDS COMPARED

The dependence of variance of coat gene frequencies on geographic dist ance was studied in stray domestic cat populations by means of analysi s of variance (ANOVA) and variance ratio test (F-test) with the data s et containing 333 samples. The procedure included the stepwise estimat ion of variances within square pieces of territory of gradually increa sing size performed separately for the Old and New Worlds. It is revea led that beginning with 200-300 km-size of square side, for the most l oci studied, these distance-controlled variances are significantly les s in the New World, thus indicating a smoother gene frequency landscap e. In both worlds, the t(b) and l alleles show significantly higher va riances than the other mutant alleles. The mean allele frequencies in the New World are significantly higher than in the western European ar ea, from where colonization look place for alleles that constitute a ' 'luxury'' gene group (O, d, l, W) presumably formed by human preferenc e. The results support in general the historical/immigration hypothesi s, i.e., that domestic cat colonization of the New World proceeded by rapid population expansion without a great gene frequency change (bott leneck-like effect). A modification is suggested for the model: a bias ed colonization sample (a founder effect) in regards to O, d, l, and W alleles.