Tortoiseshell cats show limits of cloning

tortoiseshell cat coloring

Cloning pets is a relatively new, and very expensive, procedure. It not only raises ethical questions about whether pets should be cloned when there are thousands of adoptable pets in shelters and at risk of being killed, but the few pet owners who have had their pets cloned have come to realize that while the cloned pet may look like their favorite departed pet, his or her personality may be completely different from the original.

While I won’t even try to understand the science and mechanics involved with cloning, I do have a basic understanding of genetics, and I really know tortoiseshell cats. Those of us who love cats with this distinctive coloring also know that they are very unique when it comes to their personalities, often known as “tortitude.” And now scientists are finding that tortoiseshell cats also show the limits of cloning.

IO9, a daily publication that covers science, science fiction, and the future, reported that tortoiseshell cats cannot be replicated, because parts of their genes simply aren’t there anymore.

“Tortoiseshell cats are the result of two different genes teaming up. One gene will turn the cat red, a nice solid ginger. The other will make it a black cat. Each gene is inherited from one of the tortoiseshell’s parents. Each is on one of the tortie’s X chromosomes. The tortoiseshell look is produced because of a process called ‘X-linked inactivation.’ The cells of developing embryo of the tortoiseshell cat randomly shut off one of the X chromosomes. And there’s no general consensus among the cells about which one to switch off, so each cell simply picks one. This random shut-off is why tortoiseshells have an unpatterned mix of black and red hair over their bodies.

Cloning a tortoiseshell involves taking the DNA from one cell. Since each of the cells have only one active X chromosome, when a new tortoiseshell embryo is developing using the borrowed DNA, it only has one gene affecting its coloration.

Thus, a cloned tortoiseshell kitten will generally be either black or red. Even if someone were to nab a cell from a developing embryo before the X-linked inactivation happened, the new cloned kitten would also randomly inactivate its X chromosomes, leaving two cloned siblings that don’t have the exact same color pattern.”

The article concludes:  “Life is sometimes determined to be unique, in spite of our best efforts to make it predictable.” And I, for one, am glad that this is the case.

Read the full article on IO9. For a more detailed look at tortoiseshell genetics, visit the Messybeast website.

Would you ever consider having your cat cloned?

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17 Comments on Tortoiseshell cats show limits of cloning

  1. Bernie
    June 2, 2014 at 1:34 am (7 years ago)

    I am delighted that the Torties cannot be clowned.. They are exceptional and so very unique in their coloring and attitudes. Sure some have extra Tortitude, but in the realm of all they also have an attitude. So don’t mess with them. They are expressions of natures artwork at it’s best. I love my two Torties and they are as all Torties, one of a kind.

  2. DeniseL
    March 15, 2012 at 8:39 pm (9 years ago)

    I always knew my torties were special!

  3. Susan Mullen
    March 15, 2012 at 6:04 pm (9 years ago)

    I would never clone a pet. It seems wrong to me for so many reasons. One of the best arguments against cloning was in a book I read once. I forget the name of the book, but the concept was that a living being is conceived, is born, and develops all in response to the circumstances of time and place. The time and place of cloning will always be different than the time and place of conception and growth. What works just fine in one time and place might be OK in another time and place, but it will never be “the same”, which is the goal of cloning.

    Also, the whole thing feels disrespectful to me. It does not feel like the right way to show love and regard for a pet who has passed on. Pets help us connect to Mother Nature. Cloning takes us away from Mother Nature.

    • Ingrid
      March 15, 2012 at 6:08 pm (9 years ago)

      It doesn’t feel right to me, either, Susan, and I love how you expressed it by saying that pets help us connect with nature, and cloning does the opposite.

    • EarlGrayHot
      January 29, 2016 at 3:07 pm (5 years ago)

      I agree. While I loved my last tortie and miss her so much it hurts, I would never clone her. Whatever she went through before she came to me made her the cat I loved. Those factors were unique and cannot be duplicated just as the tortie coloring cannot be duplicated. I have, however, just adopted another tortie-calico mix and she is already showing me how affectionate she can be. She is unique just as her dear departed sister was. I would never try cloning anyway because there are so many cats (and dogs) out there who desperately need homes and who can love you a lot just as my new girl can.

  4. Pam
    March 15, 2012 at 2:56 pm (9 years ago)

    I really wish that Science would apply itself to problems that are more pressing to society! It would be more helpful, IMHO, to solve such problems as alternative energy sources; how to get everyone to eat a more nutritious diet; and ways in which society can raise happy, healthy children; to name a few.

    The more I read The Conscious Cat, the more I hope I am owned by a Tortie one day!

    • Ingrid
      March 15, 2012 at 6:07 pm (9 years ago)

      I agree, Pam, there are far more pressing problems that need to be addressed by Science, although I suppose there are probably medical advances that can come about as a result of cloning research.

      And you never know when a tortie will find you…

      • Will
        January 14, 2016 at 2:57 am (6 years ago)

        Cloning research is vital. Best way to put it is, if you lost an arm, would you want a donor arm or an exact copy of your own arm? Torties rule!

  5. Esme
    March 15, 2012 at 9:42 am (9 years ago)

    While it is fascinating to me what science can do-some things are best left alone. Sure it would great if we could clone the perfect specimen without illness or ailments, however I am not in agreement with it at all. We are all different for a reason.

    • Ingrid
      March 15, 2012 at 2:00 pm (9 years ago)

      I agree, Esme, just because something is possible doesn’t necessarily mean it’s a good idea.

  6. Layla Morgan Wilde (Cat Wisdom101)
    March 15, 2012 at 9:27 am (9 years ago)

    Ingrid, what a fascinating article today. After seeing a TV show about people who have their pets cloned, it was clear the identical looking animal didn’t have the same “soul”. A copy is never an original and no, I would never clone a pet under any circumstances.

  7. Bernadette
    March 15, 2012 at 6:51 am (9 years ago)

    Wonderful explanation for cloning, and it’s still a little shocking that it can be done from one single cell. The article was great.

    A big part of the fun of living with animals is the joy of meeting new personalities all the time. As much as I have loved and missed certain of my cats, meeting them was by chance, and each meeting by chance is another opportunity to meet a personality just as unique, that will become just as dear.

    • Ingrid
      March 15, 2012 at 1:59 pm (9 years ago)

      I agree, Bernadette, the chance meetings often make for the most special relationships.

  8. Jane H
    March 15, 2012 at 6:29 am (9 years ago)

    Great piece! I’m dubious about pet-cloning as a practice, but I do find the science behind cloning fascinating.

    • Ingrid
      March 15, 2012 at 1:58 pm (9 years ago)

      Thanks, Jane. The possibilities are amazing.

  9. Marg
    March 15, 2012 at 6:18 am (9 years ago)

    No, I would not have any of my cats cloned, not because I don’t love them, but like you said, even if they are cloned, they have different personalities. I personally don’t care what color the cat is, I just love them for all their personalities and they are all totally different. I have to say, that I just got a Tortie cat and she is such a nice cat. She is so different than the other two torties that live here. But interesting subject.

    • Ingrid
      March 15, 2012 at 1:58 pm (9 years ago)

      I’m so glad you took in that tortie, Marg. And even though I obviously have a fondness for torties, I agree with you: it’s the personality that matters.


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