3 ms·
That's incredible. I wonder if you could say she's technically still alive, then, if cells with her DNA are still living?
by udp 16y ago
That's incredible. I wonder if you could say she's technically still alive, then, if cells with her DNA are still living?
- sambeau 16y agoI wonder, also, if there are more of her living cells in existence now than when she was technically 'alive'?
- SeanDav 16y ago"These immortal cells have multiplied to the point that if you were to weigh all of them that live today, they’d weigh about 50 million metric tons" I would say yeah - a couple more :)
- gus_massa 16y agoThe article says 50 millon tons, this is realy realy big. It is like 10Kg (~20 pounds) per human being alive. But according to wikipedia and [1] there are "only" 20 tons. (I think that the exact number is difficult to calculate, so 50 tons is perhaps a razonable number too.) Still 20 tons (~ 40000 pounds) is much bigger than 50 or 100 Kg (~100 or200 pound) that is the weight of a person. [1] http://hamptonroads.com/2010/05/cancer-cells-killed-her-then-they-made-her-immortal?cid=posld http://hamptonroads.com/2010/05/cancer-cells-killed-her-then...
- bedris 16y agoHer cells, when grown in culture, have been dividing and replicating for a very long time. The fidelity of a cell's replication machinery is not 100%, such that every generation, new mutations are introduced into the cell's DNA. Owing to the increased rate of cell division of immortalized cells grown in laboratory culture dishes versus those found within a living organism, the additional stresses that these cells face in an in vitro environment, and the many thousands of cell generations these cells have undergone since their derivation (in the many hundreds of laboratories that are growing some strain of these cells), the number of mutations introduced into HeLa cellular DNA makes it such that these cells are now very, very different than the original ones isolated from Henrietta Lacks.
- djacobs 16y agoTrue, but most people freeze zero-passage cells in liquid nitrogen so that such mutations don't occur. I'm not sure at what stage her cells were originally frozen down, though, or if they're routinely passed at repositories like ATCC.
- gus_massa 16y agoThese cells don’t have exactly the same DNA that she had. These are tumor cells, so the have some modifications. In particular, the cells have 82 chromosomes instead of 46 as usual in human cells. Some people think that these cells are a new specie, a specie that lives in laboratories. These cells go from culture plates to culture plates at the minimal distraction. If someday the scientific want to erase all of them, it will be very difficult because a lot of other "cell cultures" are really HeLa. There are some examples of "transmissible cancer" that does something similar in the wild, in animals instead of culture plates. The cells in these tumors are more related to the cells in other tumors of the some kind, that to the cell in the actual animal host. Examples: * Tasmanian Devil: http://en.wikipedia.org/wiki/Devil_facial_tumour_disease http://en.wikipedia.org/wiki/Devil_facial_tumour_disease * Dogs: http://en.wikipedia.org/wiki/Canine_transmissible_venereal_tumor http://en.wikipedia.org/wiki/Canine_transmissible_venereal_t...
- tocomment 16y agoWhy do the cells have more chromosomes? How can they be useful if they're so different from normal human cells?
- gus_massa 16y agoUsually (always?) tumor cell are not only immortal, they also have problems with the chromosome copy process. The extra chromosomes are copies of the normal chromosomes. The number varies in every cell line to cell line. So these cells are different, but most of their molecules are exactly like the molecules of a normal person. So they are useful to study most of the properties of humans cells.
- rbanffy 16y ago> I wonder if you could say she's technically still alive Most organ donors would, then, still be alive. That would raise some interesting questions regarding inherited fortunes.