No. 67: Jan-Feb 1990
DNA attached to a cell's surface? Such a notion was shocking to scientific orthodoxy in the 1970s. At that time, observations of the phenomenon were rejected. Even worse, funding to continue the work was not forthcoming. Happily, other researchers have later stumbled onto cell-surface DNA; and this startling phenomenon has been rescued from conformity's wastebasket.
Now that cell-surface DNA can be talked about, we can wonder aloud where it comes from and what its significance is. First, this out-of-place DNA -- thought to amount to about 1% of a cell's total DNA -- could come from either inside the cell itself or from blood-borne cellular debris. There is considerable argument on this point. Second, this cell-surface DNA does not appear to undergo replication nor does it perform any gentic coding function. Speculation is that it may somehow be involved in the immunological response of the body; for its position on the cell surface is ideal for such a role. Some researchers think that cell-surface DNA may aid in the drug treatment of T-cell lymphoma, a type of cancer. On the other side of the coin, it may mask those molecules on tumor cells that provoke immune responses. Such divergence of opinion indicates how much there is to learn here.
(Wickelgren, Ingrid; "DNA's Extended Domain," Science News, 136:234, 1989.)
Comment. If the cell-surface DNA does not come from within the cell itself, is there a possibility it might be alien DNA that somehow got into the blood stream?