Julia Thompson wrote: > On Tue, 22 Feb 2005, Robert Seeberger wrote: > >> I learned something interesting about cats last night. If you cloned >> a tortoise shell or a calico cat, the clone would be a black cat or a >> white cat but it could never be a tortoise shell or a calico. Weird >> huh? > > How does that work? > I shouldn't post when I'm tired from work. I got it a bit wrong but generally correct. A clone will be only bi-color at best, but never tri-color.
I read it here: http://www.messybeast.com/tricolours.htm >From the page: This may seem an odd topic, but if you clone a tortoiseshell cat you will end up with a cat of one or other of the constituent colours and not a tortoiseshell clone. If you clone a red/black tortoiseshell, the clone will be either red (ginger) or black. DNA tests on the tabby-and-white cloned kitten ("Cc") proved that she was a clone of her tortie-and-white genetic mother (the cat whose cell was used to create Cc). The pattern of pigmentation in multicoloured animals is the result of genetic factors combined with developmental factors within the womb. This means bad news for owners who want an exact replica of a tortoiseshell or calico cat. Why isn't Cc also tortie-and-white? The answer is due to 'X-linked Inactivation'. Tortoiseshell cats have two X chromosomes, one carrying the gene for orange coat colour and the other carrying the gene for black coat colour. As the embryo develops, a process called 'X-linked inactivation' occurs in its tissues. One or the other X-chromosome in every cell in a tortie cat embryo is randomly inactivated. This only shows up in pigment producing cells, producing the familiar tortie effect. Regardless of which cell was used to produce Cc, because that cell is already an adult cells, one or other of the cell's X chromosomes would have been inactivated while the donor cat was an embryo. Cc had an equal chance of being orange-tabby-and-white or black-tabby-and-white, but would never be tortie-tabby-and-white. Unless a way can be found to undo X-linked inactivation at the embryo stage, owners wishing to clone a tortoiseshell cat will have to settle for a cat of a different colour entirely. If the X-linked inactivation can be reset, the inactivation is a random process so the clone will have the right colours, but not in the same places as the donor cat - it may have well-defined patches of colour while the donor cat was thoroughly brindled. xponent Cat Science Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
