|
|
The Manx as well as Maine Coon and Bengal have been and are being used in breeding programs throughout the country. This is not an endorsement nor a critique of that practice. I will address only the Manx and the genetics associated with the Taillessness gene we all have to deal with in breeding bob tailed cats.
Taillessness is a genetic anomaly. The effects of the taillessness gene(s) plays a role in the development of not just the tail but the entire spinal column. It also can effect certain internal organs as well as spinal column development. The Manx gene when homozygous { MM } is lethal. This means the can never be “true breeding” because they die prior to birth from carrying the MM gene.
While the Manx gene is lethal when homozygous it also appears to be semi-lethal at other times as well. Some indications that you have Manx genes playing a role in your breeding are : an increased number of females in your litter, smaller than average litter sizes ( 3-4 ) kittens per litter, and the obvious structural abnormalities involving the spine, hips, and internal organs.
There are four types of taillessness 1.) the true Manx which is commonly referred to as “rumpy”, in this type there is a complete absence of tail vertebrae. Often there is in fact a dimple at the point where a tail would normally be. 2.) The “rumpy riser” type is characterized by a small number of tail vertebrae, sometimes fused together making the tail seem to be completely or somewhat inflexible. 3.) The third kind of tail is the “stumpy”, in this type the tail is often times longer but can display obvious signs of malformation such as kinks or knots, and knobs. 4.) The last type of tail is the “longie” this type of tail is shorter than a “normal” length tail seen in long tailed cats but longer than the three other types. It also appears to be more normal in that it is flexible and displays little or no abnormalities in structure. Some studies have shown that the Manx gene manifests its self through modifying polygenes.
Other skeletal influences of the gene(s) present themselves
as shorter individual vertebrae in the fore part of the spine. In
the aft part of the spine there is not only a shortening of the vertebrae
but a decreased number of them as well. There is also an increased number
of fused vertebrae in the aft region of the spine.
There can also be involvement of the sacral and pelvic structures,
that is, the fusion of these structures as well as the vertebrae. Bowel
problems can also occur due to narrowing of the opening at or near the
anus. This can manifest itself as incontinence or constipation as well
as inflammation of the rectal lining. In some severe cases spina
bifida ( open spine) may occur . This may or may not present as an obvious
externally open spine.
I will leave you with this thought, in my opinion, I do not think it
is wise to breed any cat that is a “rumpy” unless it has so many other
outstanding traits that they out-weigh the inherent difficulties associated
with the Manx gene. I hope this has served to help some of you to understand
why using only “perfect” tails is paramount in any Bob tailed cat breeding
program.
Allen Prichard
babybobs@cybertrails.com
http://www.cybertrails.com/babybobs/
