X-Message-Number: 8439 From: (Thomas Donaldson) Subject: Re: C57BL/6J mice and aging Date: Mon, 4 Aug 1997 00:26:18 -0700 (PDT) Hi again! I sit here and write this by memory alone, with a bit of consultation of my own book. 1. It is not strictly correct to call one set of animals, which live for a long time, "controls" in other experiments. Yes, C57BL/6J mice do live a long time. A significant number of the experiments Doug cites were NOT done with C57BL/6J mice, so that the MEANING of his bibliography becomes obscure. 2. Although work to identify the genes which affect lifespan in mammals has as yet not gone long enough for any conclusions, it's clear that genetics plays a large role. The easiest way to see this is to observe other species all of which live for widely varying lifespans. Moreover the number of genes affecting lifespans is probably small, since closely related species can have wide differences in lifespan. Chimpanzees only live half as long as human beings, for instance. 3. OK, so C47BL/6J mice live a long time, for mice. This is likely to be caused by their inheritance of alleles for lifespan genes which make them live longer. Similar genes may well work with human beings. However a drug can still act against aging even if it does not increase the lifespan of someone with very good lifespan genes: it makes up for their absence in most people who take it, and may very well do so by affecting the same metabolic events that good lifespan genes affect. (There's lots of research to be done here, people ... its not enough just to show that a drug increases lifespan. We want to know WHY). Naturally if the drug partially substitutes for the lack of good genes, someone who had such genes would not be affected by it. The same, of course, may be said of mice. 4. Such drugs may also help people (or mice?) who aren't as resistant as others to common pollutants, etc etc. That issue slides off into the issue of aging, but can still be distinguished from it intellectually. And since no one can live in a perfectly clean unpolluted environment, extra antioxidants etc may be very useful --- even if they DON'T act directly against aging. Best and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=8439