Research overview: geographic frequencies of cat coat-colour alleles

Beginning in the mid-twentieth century, population geneticists used the visible coat-colour and pattern alleles of free-roaming cats, such as the orange, non-agouti, dilute and white-spotting variants, as natural markers to track human migration and gene flow. This overview surveys that body of work, which mapped allele frequencies across cities and continents and detected gradients reflecting historical settlement, trade and colonization, including signatures along Viking and maritime routes. Because cat coat genes are easily scored without laboratory tools, they offered an early, low-cost window into population structure before molecular methods. The survey discusses both the insights gained and the limitations of inferring human history from cat genetics, and how modern DNA studies have refined and sometimes revised these classic conclusions.