Gene frequencies in the domestic cats of york: Evidence of selection

Abstract

1. The gene frequencies for coat colour of cats have been estimated from the animals recorded at the animal shelter in York. 2. The gene frequencies in York are similar to those in other cities in western Europe and in the north east United States: Dominant white is infrequent as in all other cities; Maltese dilution is at a frequency similar to that of European cities rather than of the United States; non-agouti is at a very high frequency, a little higher than that in London; blotched tabby is at the high frequency characteristic of north-west Europe; and orange is at a higher frequency than in London, seeming to confirm the suggestion that this allele is not favoured in urban environments. Frequencies in York are almost identical with those in southern England. 3. The numbers of black, tortoiseshell and orange females (the sexlinked locus) indicate that the cats in York mate roughly at random with respect to colour, but the combined data for York and all other cities so far published show an overall significant excess of orange alleles in males and of black alleles in females. This suggests, according to standard theories of selection at sex-linked loci, that the locus in question is under some kind of selection, natural or artificial. 4. As many cities have been surveyed using shelters for unwanted animals, it is not clear in which direction selection is tending, but in York the frequencies of the black-orange locus seem to differ between stray and pet cats. © 1971, The Genetical Society of Great Britain. All rights reserved.