DOLLY!!!

Sheep cloned by nuclear transfer from a cultured cell line. 
Campbell KH, McWhir J, Ritchie WA, Wilmut I.

Abstract

Nuclear transfer has been used in mammals as both a valuable tool in embryological studies and as a method for the multiplication of 'elite' embryos. Offspring have only been reported when early embryos, or embryo-derived cells during primary culture, were used as nuclear donors. Here we provide the first report, to our knowledge, of live mammalian offspring following nuclear transfer from an established cell line. Lambs were born after cells derived from sheep embryos, which had been cultured for 6 to 13 passages, were induced to quiesce by serum starvation before transfer of their nuclei into enucleated oocytes. Induction of quiescence in the donor cells may modify the donor chromatin structure to help nuclear reprogramming and allow development. This approach will provide the same powerful opportunities for analysis and modification of gene function in livestock species that are available in the mouse through the use of embryonic stem cells.



Nature. 1996 Mar 7;380(6569):64-6.

Why is this cool?
 The 90s were awesome for many scientific reasons: the sequencing of the human genome project was started, the first crystal structure of farnesyl pyrophosphate synthase was solved, and cloning became something serious. In 1996 at the Roslin Institute, researchers cloned a sheep.

What exactly does it mean to "clone" something? To understand that, we need to know that unlike bacteria, sheep cells have a defined and segregated structure for containing the genetic material called the "nucleus." For constructing Dolly, the researchers removed the nucleus from a sheep cell line which they they had cultured and then they inserted that into an embryo that had its nucleus removed previously. This embryo was then inserted into a ewe and they waited until their MIRACLE OF SCIENCE BIRTHED A NEW ERA OF HUMAN POSSIBILITY!!!! To culture a cell line means that they took cells from some random sheep (actually it was not completely random) and grew them.
 A few thoughts on transferring genetic material to embryos. I would like to reveal some of my own ignorance and speak outside my comfort zone, so correct me if I am wrong.

When you are born, your genetic material is "fresh" and "clean" meaning that it has not accumulated the many deadly mutations that cause horrible things like cancer. you may ask "But the genetic material that went into making me came from someone who had the time to accumulate deadly mutations that cause cancer, why am I not born with it?" I just don't know why that is not the case, but years of clean doctor visits have assured me that I and all young people are not born with cancer. So, when you transfer genetic material that has had time to accumulate deadly mutations into an embryo, you would would expect that organism to be prone to cancer. Is this why Dolly was taken from us while she was so young? I don't know. There are many ideas. The techniques that make Dolly possible open a new avenue for studying aging on a genetic level in higher order organisms.
 With all this in mind, we can finally look at Michael Keaton's seminal work Multiplicity (1996) and answer some real questions:

Could he suddenly have full grown clones? No, Dolly was born and raised.
Would clones have to leave and get new jobs as pizza makers? Most likely, pizza making is a challenging line of work and it requires the skills of a sassy gay man, a butch macho man, and some whack job.