Free Frankenstein's Cat: Cuddling Up to Biotech's Brave New Beasts by Emily Anthes

Missyplicity Project revealed a large potential market for copied pets, and Hawthorne and Sperling launched a company to make it rain cloned cats and dogs. On February 16, 2000, Genetic Savings & Clone (GSC) was officially born. At first, the company funded research and offered tissue banking, allowing people to store their pets’ cells until cloning technology matured. (One page on the GSC website at the time suggested “a futuristic stocking stuffer: a gift certificate redeemable for the preservation of the animal’s DNA … It’s like a ticket to the future, today!”) The company was an instant sensation.
    Only one small thing lay between a pet owner and his clone: getting the darn ditto machines up and running. Although the impetus for the entire endeavor was a well-loved mutt named Missy, with both cat and dog owners clamoring for cloning, the A&M team decided to try replicating both species. Much to the disappointment of dog lovers everywhere, success with cats came first.
    The lucky feline was a calico cat named Rainbow, and the first step in copying her was swiping a sample of her cells. When it comes to cloning, nearly any cell that contains a complete set of genes will do. (Recall that Dolly came from a mammary cell, and skin cells are also commonly used.) The A&M team knew that other scientists had had good luck with cumulus cells—the specialized, mature cells that surround a developing egg—so that’s what they harvested from Rainbow.
    But you can’t simply stick a random cat cell into a uterus and expect a new feline to grow. Researchers needed to get Rainbow’s biological code into the proper vehicle: an egg. To do so, the scientists employed a method known as somatic-cell nuclear transfer, the same approach the Scottish team had used to create Dolly. The technique involves extracting the DNA from an unfertilized egg and replacing it with instructions for making a clone. (The procedure is not unlike removing the custard from the middle of a Boston cream donut and refilling the donut with jelly.)
    Westhusin and his team harvested ova from a clutter of lady housecats. They poked a tiny, turkey-baster-like tool called a pipette into each egg and sucked out its nucleus, leaving the rest of the cellular machinery untouched. The scientists took one of Rainbow’s cells and placed it inside the newly “enucleated” egg, between the inner and outer membranes. This cell-inside-a-cell was then shocked with an electric current that turned the membranes of both cells into Swiss cheese, creating holes that allowed the genetic contents of Rainbow’s cell to flow into the egg. The egg, thus “tricked” into believing it had just been fertilized by a sperm cell, began to grow and divide, just like a normal embryo.
    The researchers ended up with three cloned embryos, each of which contained Rainbow’s DNA. They transferred these embryos into the uterus of a brown housecat named Allie. Although only one of these feline fetuses survived to term, that was enough, and on December 22, 2001, Allie delivered a little, mewing kitten. Testing confirmed that the kitten was indeed Rainbow’s clone, and she was given the name CC, short for “Carbon Copy.” *
    CC’s name aside, technically, clones produced through nuclear transfer are not quite perfect copies of their genetic donors. Though the overwhelming majority of genes reside in a cell’s nucleus, mitochondria—which produce energy for the cell and sit in the cytoplasm outside the nucleus—contain their own little genomes. Because nuclear transfer leaves the cytoplasm of an egg intact, CC had the mitochondria, and mitochondrial DNA, of her egg donor, rather than from her “twin,” Rainbow. Since the amount of DNA involved is so tiny, however, most discussion of clones ignores this small genetic discrepancy.
    CC’s birth alone was a remarkable achievement, especially given cloning’s staggeringly high failure rate. Some of the embryos created by nuclear