Immortal human cells growing and developing outside the body

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Immortal human cells growing and developing outside the body

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The immortal remains of Henrietta Lacks.
When human body cells are removed and put into a cell culture, they weaken and die quickly, usually within about 50 divisions. Without the rest of the support structure—a heart, blood circulating, a digestive system and so-on—body cells can't survive. Body cells also age, so even if you were to simulate the body's environment in a test tube or petri dish, the cells would eventually perish anyway. The basic mortality of the cells reflect the basic mortality of the organism they comprise, which is why there's no fountain of youth or medicinal procedure that'll give you biological immortality.

There is, however, one human being who is biologically immortal on a technicality, and her name is Henrietta Lacks. In 1951 she showed up at John Hopkins Hospital in Baltimore, complaining of blood spotting in her underwear. Samples were taken of her cervical tissue and sent to a lab for analysis, which came back with a diagnosis of cervical cancer.

The cancer was caused by the Human papillomavirus, which is a sexually transmitted disease. Most variants of this virus are harmless, but some are known to cause cervical cancer, as in Henrietta's case. After her diagnosis and before attempts to treat the disease with radium, another sample from the tumor was sent to George Gey, who was the head of tissue culture research at Hopkins. Gey discovered that the cells from Henrietta's tumor would not only survive and multiply outside of her body, but they didn't age either. These cells were basically immortal.

And they're still alive, even though Henrietta herself died of the cancer on October 4th, 1951. Now, HeLa cells are about as common in biological research as the lab rat and the petri dish, and are still being grown in an unbroken lineage from the cells originally harvested from Mrs. Lacks in 1951. They're used in cancer research because a scientist can perform experiments on them that otherwise couldn't be done on a living human being. They were also used in the development of the Polio vaccine, making Henrietta somewhat of a posthumous hero to millions.

But say you're a scientist looking at HeLa cells under a microscope. They live independently of the body they came from. They reproduce (faster even than other cancerous cells). They consume, excrete, and do everything an independent living organism usually does. A thousand years from now there will still be HeLa cells multiplying and living, even some of the original cells sampled from Mrs. Lacks, even though Henrietta Lacks herself has long since passed away. Is this a new species?

In 1991 the scientific community decided it was, and blessed HeLa cells with its own genus and species: Helacyton gartleri, named by Van Valen & Maiorana.

That would make Helacyton gartleri an example of speciation, which is when a new species is observed developing from another. In this case, the development is from a chordate (homo sapien) to something that's more like an ameoba (a cross-phylum mutation), giving us an animal with a mostly human genotype, but which does not develop into a human-like phenotype. Since this event occurred in nature when the papillomavirus transformed Henrietta's cells, and not in the laboratory, it's a strong piece of evidence supporting Evolution (although not one that suggests you could go from an ameoba to a chordate, which would probably take more than one mutation).
By netchicken: posted on 21-12-2005








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