From a genetic point of analysis, the Thoroughbred colt, HANSEN (2009) is of “gray” (G/g) color, not white. This is visually evidenced (phenotype) by the fact that his subjacent skin (not the hairs) is of a dark color, rather than pink, as it occurs with all white equines. See the photos henceforward.
White equines sports white hairs along with pink skin. It is important to mention that although HANSEN fashions a pink lower lip (in Spain they call that design: “bebeblanco” [white paint drinker]) this does not mean that he has an overall pink skin.
He is a normal “gray”. The only curious difference here is that he is “graying” out (or “whitening out”) at a very rapid pace. Such a rapid pace is not the norm for a gray, but it is not that scarce anyway. Back in the 1970s a horse named Vigors (Roan H 1973, by Grey Dawn II – Relifordie) who curiously was also named after the last name of a doctor, was perhaps more white-looking than Hansen. From a genotype point of view, Vigors was also a gray (albeit, he was registered by the misleading term “roan”), just like Hansen. Seems like Hansen’s sire, Tapit, has the tendency of throwing many gray colts and fillies that white-out at a more rapid pace.
http://www.search.com/images?q=HANSEN%2 ... 31&index=4
http://news.yahoo.com/photos/jockey-jos ... 33260.html
http://www.search.com/images?q=HANSEN%2 ... 31&index=2
http://www.drf.com/news/breeders-cup-wi ... k-his-side