No. 50: Mar-Apr 1987
How do cancer cells develop resistance to lethal chemicals? The clues seem to reside in extrachromosomal DNA that carries drug-resistance-conferring genes from one cancer cell to another. Cancer cells dying from chemotherapy may, for example, cast off extrachromosomal DNA that carries information on how to combat the chemicals. Other factors may also be at work, but basically we have only suspicions.
(Silberner, Joanne; "Resisting Cancer Chemotherapy," Science News, 131:12, 1987.)
Comment. Insects and other organisms also acquire resistance to chemical poisons. Does extrachromosomal DNA play roles in these instances, too? Can Information coded in extrachromosomal DNA be passed from one species to another, say, via insect bites?