In February 1997, the month of my birthday (not that that had anything to do with it), Dr. Wilmut, an American scientist in Scotland, wrote a rather short article that stunned the world. For me, it was one of those, "I remember what I was doing when..." moments. I was walking from the medical sciences library at Texas A&M University back to my lab. I picked up the school newspaper on my way and did a double-take when I saw the "Adult Mammal Cloned!" headline. Figures. There I was in the field of biochemistry and genetics and I first get the news from the school newspaper (which published it the day after it came out in Nature). I did have an excuse, though: I was so busy on my own research project and classes that I was behind on my general journal reading. *grin* However, I did immediately go find myself a copy of Nature to read the actual article.

I was ecstatic. You see, before then, the scientific dogma was that one could not clone from an adult mammal, and I love it when scientific dogma gets thrown out. People had tried with frogs/tadpoles, but the tadpoles never developed into frogs. Something just didn't go right and they never got any further than that. However, we have been able to clone from embryos for many years. In fact, a few years before Dr. Wilmut made his announcement, the New York Times carried a front page headline announcing the first "cloning" of a human embryo. That was no big deal to the scientific community. We'd been able to do that for years, and had done it for other organisms. No one had ever done it with a human before because of the ethical implications. The procedure, however, is relatively simple. You take an early embryo and basically just split it into two. Each half will start to develop again and you'll have two identical wholes as the finished product. The main difference is that embryonic cells are not differentiated and adult cells are differentiated. Differentiation is when certain genes in a cell type are active, and others inactive, so that that cell has developed as a certain "type" of cell: a liver cell, or a muscle cell, or a neuron, for example.

What Dr. Wilmut did was much different, and totally unexpected. He took a mammary epithelial cell (an adult cell) from a sheep and an egg cell from another sheep. He removed the nucleus from the egg cell, and then arrested the donor nucleus of the adult cell in a cell state called G0. In this stage, the cell is "starved" of nutrients and becomes quiescent, or inactive. One of the main reasons why scientists had not been able to successfully clone from adult cells prior to Dr. Wilmut's experiment was because they had not induced the adult cell to become inactive.

Once the adult cell was "sleeping," Dr. Wilmut fused the adult cell nucleus with the egg cell (that had its nucleus removed). From this fusion, Dolly, the first sheep cloned from an adult cell, was born. However, the process wasn't very efficient. Out of 277 tries, only one was successful.

But could this be done with other species? Yes! In July of 1998, another team of scientists announced that they had cloned mice from differentiated adult mouse cells. Can this be done with humans? Almost certainly. Should this be done with humans? Most scientists and philosophers say, "no."
 
 

• What is a clone? Does a clone have a Soul?

A clone is simply a genetic duplicate of another organism. Essentially, it is an identical twin. Do identical twins have "souls?" Yes. Clones have "souls," as well. A human clone would be just as human as its genetic duplicate. However, clones would not be the same age because a clone derived from an adult cell would still have to develop normally (from an embryo, to a fetus, and then go through childhood to reach adulthood). You don't end up with an "instant adult clone".
• Would a clone have the same personality as the original person?

Yes and no. Personality is influenced by both genes and environment. Clones would have as similar personalities as do twins who are raised in different environments.
• How do clones differ from identical twins?

Identical twins are from the same egg, as are clones. However, a clone differs from its original in mitochondrial DNA. Mitochondria exist outside of the nucleus and replicate independently of the nuclear DNA. Scientists believe that mitochondria originated from separate organisms that took up a symbiotic relationship with cells. Because the clone received its nucleus from the adult, but its mitochondria from the egg cell, it will have different mitochondrial DNA than the adult from which it was cloned. However, mitochondrial DNA, to my knowledge, has no practical effect on the cell.
• Would a clone age normally?

Right now, we don't know, but we think not. When Dolly was first born, there was some talk over whether she would age normally. Were her telomeres normal? Telomeres are the "ends" of DNA, and telomeres shorten every time a cell divides. When the telomeres get too short, the cell can no longer replicate the DNA and the cell goes into senescence (aging) and eventually dies. Dolly was derived from an adult cell that presumably had shorter telomeres than a baby sheep cell would have had. Was the telomeric DNA reset when it was fused with the egg cell? Apparently not. Dolly's telomeres were indeed shorter than they should be for her age. Dolly, now over two years old, has the telomeres of a six to eight year-old animal. What happens when you have shorter telomeres than you should have? Well, the "premature aging" disease known as Werner's Syndrome is marked by shorter telomeres. However, it remains to be seen whether Dolly will have a normal lifespan. Several questions remain regarding the viability of cloning for both the host mother and the cloned animal. Cloning is still a young science, and it appears that embryo clones are less likely to grow to term and are more likely to have developmental abnormalities. For the most recent update, see the article, Dolly: Young on the Outside, Old on the Inside? at https://members.tripod.com/~Methos_5000/dollyold.html
• Can my dog be cloned?

Probably. Texas A&M has already taken on the project after being paid $2.3 million dollars to clone Missy, an 11-year-old border collie mix (The Missyplicity Project).

Clone News and Cloning Information

New Scienist: Cloning Report
 

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