possible colors for Zenyatta andTapit foal
Color genetics in horses works something like this: there are two basic body colors in horses ie brown (like Z) and chestnut (like Secretariat). All horses will exibit one of these underlying body coat colors. Brown is the dominant color and chestnut is recessive. On top of these two basic colors there are a number of other factors which may come into play. One of these is the gene for graying which is dominant. The grey foal starts out either chestnut or brown and becomes greyer and greyer over time. Young greys may be very dark and exhibit lovely dapples (like Spectacular Bid)-but these will fade with time until the coat is nearly white. Often the older grey horse will have evenly spaced flecks of its original body color and is then called "fleabitten grey". Hansen (by Tapit) is a rare example of a grey that is nearly white at the age of three. Because grey appears to be dominant, at least one parent must be grey for the colt to be grey. This is true of the dominant basic color brown as well. Because chestnut is recessive, a horse may carry this gene without showing this color. If Tapit and Zenyatta both carry a "silent" chestnut gene their colt COULD be chestnut. If Tapit sires any chestnut foals this shows us that he carries the recessive chestnut gene. Zenyatta quite likely carries two genes for brown (from looking at the colors of most of her relatives for several generations) but if she has just one chestnut foal this will prove me wrong. I suspect the Tapit baby we will be waiting for will be dark brown with a 25% chance of greying. What do you think?