Here since you are found of quoting other people this is one of the things I think is relevant here. I hope Nick is ok with me posting this and maybe he can post his 2 cents as I know he pops in from time to time.
Tigers froma tigerXnormal breedings are only heterozygous, as they can only recieve one copy of the tiger gene. the outcome of breeding tigers to tigers will depend on if the parent tigers are heterozygous or homozygous tigers and at the moment the variablility of the gene in its heterozygous state can make it difficult to determine.
Nick