So, in summary, we can't clone tortoiseshell cats because we can't clone their <i>patterns</i>?<p>In that case we can't clone anything - identical twins don't have identical fingerprints.<p>This also ignores the problem of "active" chromosomes (even though it relies on it). Well sure, you'll get one that's active, and that can't be used directly to clone a tortoiseshell cat into another tortoiseshell cat - but that will only be true until we can reactivate the inactive one.<p>A cursory glance through Wikipedia suggests X-inactivation isn't a well-understood area of genetics, so I propose it's not an <i>actual</i> limit, but that it lies beyond our current "limit of understanding". Calling it impossible is pure conjecture, but probably makes for a more link-baity article.
"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."<p>The different colour patterns part is true for any cloned cat's markings, not just clones of a tortoiseshell.<p>The cloned cat "Cc" who hit the news a decade ago was a tabby-and-white clone of a calico cat; calico patterns also result from having the black coat gene on one X chromosome and the ginger coat gene on the other, which is why calico and tortoiseshell cats are almost all female, and why ginger cats are three times more likely to be male than female. Trisomy does occur in cats but very rarely.
So randomness is an inherent guaranteed feature of life itself. Imagine if this applied universally to skin color too. What would our prejudices be then? Cue 1960s <i>Star Trek</i> episode where one guy is white on left side while the other is white on his right side...
I can't help but be reminded of the various copy protection schemes they used with CD/DVD disks, such as SafeDisc. It feels like this is "nature's copy protection scheme", if you forgive the cliché.
We're still working with the primitives, the biological equivalent of machine code. Even when we get to genes we're talking about pre-defined functions which call external libraries (the epigenetic and environmental factors) that we are limited to splicing around.<p>The quantum shift will come when we are able to abstract the genetic and epigenetic functions. The metaphor has yet to shift.
I think the io9 author is striving here to emphasize a favored, romantic conclusion: "No matter how advanced the technology, there is no way to clone a certain kind of animal. Life is sometimes determined to be unique, in spite of our best efforts to make it predictable."<p>I expect it's equally likely a way to reset the X-linked-inactivation within a single cell will be discovered, so while the coloring of the clone won't be a perfect copy, it will be a product of roughly the same random process as the template cat. (Perhaps the reset would even be possible in adult cells: give your cat a pill to rescramble its colors over the course of a shedding cycle, or force it one way or the other.)<p>Of course there are all sorts of other confounding influences, such as horizontal gene transfer and chimerism, both of which will probably turn out to be more important than usually assumed. But given a few hundred years, the error in 'cloning' an organism can likely be made almost imperceptibly small.
Torties are great, loyal cats--they can have a bit of an attitude though. :) Here's my little tortie girl: <a href="http://i.imgur.com/ilSqNl.jpg" rel="nofollow">http://i.imgur.com/ilSqNl.jpg</a>