coat color in dogs. DNA studies are yet to confirm the existence of these genes or alleles but their existence is theorised based on breeding data: F (flecking) locus The alleles at the theoretical F locus are thought to determine whether an animal displays small, isolated regions of white in otherwise pigmented regions (not apparent on white animals). Two alleles are theorised to occur at the F locus: F = Flecked f = Not flecked (See ticking below, which may be another name for the flecking described here) It is thought that F is dominant to f. G (progressive greying) locus The alleles at the theoretical G locus are thought to determine if progressive greying of the animal's coat will occur. Two alleles are theorised to occur at the G locus: G = Progressive greying (melanin lost from hairs over time) g = No progressive greying It is thought that G is dominant to g. The greying gene affects both eumelanin, and to a lesser extent phaeomelanin. In the presence of Em/- the eumelanin mask will be unaffected and remain dark. Grey dogs are born fully coloured and develop the greying effect over several months. New hairs are grown fully coloured but their colour fades over time towards white. Greying is most evident in continuous-growing coats (long + wire + curly) as individual hairs remain on the dog long enough for the colour to be lost. In short-haired dogs, hairs are shed out and re-grown before the colour has a chance to change. Premature greying, in which the face/etc. greys at a young age is not caused by G and has not been proven to be genetic. T (ticking) locus The alleles at the theoretical T locus are thought to determine whether an animal displays small, isolated regions of pigment in otherwise s-spotted white regions. Two alleles are theorised to occur at the T locus: T = Ticked t = Not ticked It is thought that T is dominant to t. Ticking may be caused by several genes rather than just one. Patterns of medium-sized individual spots, smaller individual spots, and tiny spots that completely cover all white areas leaving a roan-like or merle-like appearance (reserving the term large spots for the variation exclusive to the Dalmatian) can each occur separately or in any combination. The effect of the ticking is to add back little coloured spots to areas made