While a Manx must fall within either the rumpy or riser classification in order to be considered for showing, the tailed Manx is necessary for avoiding genetic complications. This is due to the dominant gene that is responsible for the Manx’s lack of tail. A Manx with two copies of this dominant gene is at extremely high risk for side effects due to the over-shortening of the spine. It is for this reason that rumpy or tailless Manx cats are always bred with a tailed Manx to minimize the risk of genetic defect. As a result a litter of Manx kittens will usually include varying tail lengths. | While a Manx must fall within either the rumpy or riser classification in order to be considered for showing, the tailed Manx is necessary for avoiding genetic complications. This is due to the dominant gene that is responsible for the Manx’s lack of tail. A Manx with two copies of this dominant gene is at extremely high risk for side effects due to the over-shortening of the spine. It is for this reason that rumpy or tailless Manx cats are always bred with a tailed Manx to minimize the risk of genetic defect. As a result a litter of Manx kittens will usually include varying tail lengths. |