Is Rachel a bob-tail too Rosanne? We have one like her...Phoebe has about four vertebrae in her tail and is a short-hair also, her sister Susie (long-haired) has only two and brother Sherman has a half-tail like his dad Winston had. Brother Simon (short-haired) and other sister Hannah (long-haired) have normal tails. Ours have Russian Blue/Manx/Angora and possibly some Siamese.
According to a genetics professor I met in Oregon, cat genetics are the most complicated there is.