Inbreeding is very common within the horses that mysteriously disappeared from the track. Northern Dancer appears inbred within 4 of his 6 descendants. Spicer Cub and Big Brown are inbred from Northern Dancer in the 3rd generation on both their sire and dam side. Although not as frequent in the inbred horses, Bold Ruler is, once again, a popular sire. He is inbred in 3 of his 5 descendants, but with the earliest generation being the 4th generation. Big Brown and I'll Have Another, both known for their failed Triple Crown attempts and controversial use of pain killers and steroids, are both descended from Princequillo; however no inbreeding of Princequillo is seen within their bloodlines, nor within any of the other mystery horses' bloodlines.
The dam bloodline also has a great deal of inbreeding, with Gold Digger, Miss Disco and Geisha each appearing within the bloodlines. The 5th and 6th generations are where the most inbreeding occurs. Miss Disco and Gold Digger appear to be the most popular dams, with only one of Gold Digger's descendants, Violence, remaining not inbred. Violence is also a descendant of Geisha, so it is difficult to determine which dam could pass on "genes" that could cause injuries and force these racers into early retirement.
All of the "Mysterious Disappearances" horses could link into both bloodlines.
The dam bloodline also has a great deal of inbreeding, with Gold Digger, Miss Disco and Geisha each appearing within the bloodlines. The 5th and 6th generations are where the most inbreeding occurs. Miss Disco and Gold Digger appear to be the most popular dams, with only one of Gold Digger's descendants, Violence, remaining not inbred. Violence is also a descendant of Geisha, so it is difficult to determine which dam could pass on "genes" that could cause injuries and force these racers into early retirement.
All of the "Mysterious Disappearances" horses could link into both bloodlines.