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Most Popular Human Cell In Science Gets Sequenced
ananyo writes "The research world's most famous human cell has had its genome decoded, and it's a mess. German researchers this week report the genome sequence of the HeLa cell line, which originates from a deadly cervical tumor taken from a patient named Henrietta Lacks (Slashdot has previously noted a film made about the cells and there's a recent mutli-award winning book on Lacks). Established the same year that Lacks died in 1951, HeLa cells were the first human cells to grow well in the laboratory. The cells have contributed to more than 60,000 research papers, the development of a polio vaccine in the 1950s and, most recently, an international effort to characterize the genome, known as ENCODE. The team's work shows that HeLa cells contain one extra version of most chromosomes, with up to five copies of some, and raises further questions over the widespread use of HeLa cells as models for human cell biology."
That's not Ms. Lack's genome anymore. The summary says it has more than the usual number of chromosomes. Cancer cells generally lose the ability to maintain their genomes, they become very unstable, allowing a bizzare, short-term form of evolution to occur. More mutations allow the cancer to get better at proliferating and invading, at least right up until the host dies. Usually, anyway, HeLa is or was unique in that it managed to escape it's own doom, much like we might need to do with Earth.
Sorry, got off topic there. Anyway, cloning HeLa cells, as in putting the genome into a fertilized egg like Dolly the sheep, that would probably not make a complete embryo. I'm not familiar with HeLa's genome, but I think it's likely they've lost the ability to control cell division, cell death, and/or cell differentiation. You need those processes to make anything that looks like an embryo. You'd likely end up with just another petrie dish of HeLa cells. It would be a neat if ethically questionable experiment.
You're exactly right, and this type of criticism does come up occasionally when using HeLa. This is a cell line that is prone to mutation that has been been cultured artificially for more than half a century: it has evolved to live in a dish. It's not comparable to taking primary cells from a fresh healthy (or cancerous) human cervix. Additionally, it's fairly certain that HeLa has differentiated into a wide number of distinct cell lines at this point, though we still generally refer to it as a monolithic cell line.
It does not invalidate studies using HeLa, but it kind of highlights that HeLa is more properly viewed as a model organism (i.e. an easily bred life form that can teach us about basic biological principles, and is also close enough to humans to be medically relevant). And this is how it is used -- biologists are not unaware of the caveats associated with these lines.