::By your standards, the Gray gene doesn't exist.  They don't have a test for it, either.  And, if you read the Mau abstract, there does seem to be evidence for the gene, they've narrowed down the probable location of the gene.  What is not known is if it has linkage to Sabino, and sabino may be caused by a number of different genes, of which only SB1 has been mapped:  "So far, it is not known whether dominant white (W) and sabino spotting (S) share a common genetic background. In this study, a pedigree consisting of 87 horses segregating for dominant white (W) was used to genetically localize the horse (W)-locus. Microsatellite ASB23 was found linked to (W), which allowed us to map dominant white to a region on horse chromosome 3q22."  So I'd say it is overkill to call W an "unproven" theory, especially when most of the dispute isn't among experts so much as among breeders who are not geneticists.

Pearl and Silver Dapple
I have no problem with someone adding Pearl to the chart.  If there isn't a wikipedia article on it, maybe that needs to be done too.  There is an article on Silver dapple, but I don't think data is in the chart yet here. I also am OK with creating some consistency with the gene symbols.  But, I  haven't the time to do it. Someone else sure can.  Best not to start a nomenclature fight, whatever is the "majority" view probably best (maybe a paragraph explaining other terminology would help.)