Cats
dilution gene (d/d) at the D locus. In any case, “d” causes blue dilution i.e. black to grey. “d”
is one of the three genes involved in melanosome transfer and translocation. The unexplained
“Ukraine chocolate” seems due to a gene for which there is no test (at least in the cat).
Possible candidates are the other two melanosome transfer and translocation genes: Myosin
Va (MYO5A) and RAB27A. Genes involved in the synthesis of eumelanin other than
TYRP1, for example, TYRP2, are also possibilities. The other known dilutions in the cat are
the extinct Barrington Brown cats (none of which were bred outside of a laboratory colony)
and the single example of a pink-eyed dilution cat.
UNDETERMINED DILUTION
There are 4 cats of Thai descent whose dilution factor hasn’t been genetically identified.
The first of these is Mai Thong. In January 2015, I received information and photos of a
native Thai cat that TIMBA hoped to use in the Suphalak breeding programme. Nolan
annaabi.ee 
