September 21: Questions for in-class discussion about the cause(s) of Multiple Sclerosis* Hint: Does this tell you whether the disease is caused by genetic abnormalities = mutations? * If 100%, or nearly 100% of identical twins of victims of some disease also got that same disease, but the % who also got the disease in non identical twins, or other sisters was only 5%, or less, how would you interpret that? II) Can you think of any reason to be curious whether this twin frequency might be lower (or higher) the farther north the twins grew up (Canada as compared with the US, New York as compared with North Carolina, or as compared with Florida, or Texas)? * Hint: The higher rates at northern latitudes are usually thought to have some environmental cause, like not enough sunlight, some effect of cold temperatures, less exposure to parasite infection by going barefoot; One student in this class suggested the strength or angle of magnetic fields. Or maybe it's a disease carried by some northern kind of animal. (Let's hope is's not Canada Geese!) ** Note: Some very good and serious epidemiologists have considered that the % immigrants from Scotland or Scandinavian countries might cause the North-South effect, by some genetic susceptibility. *** Alternatively,lets assume for the moment that the North-South difference is environmental: Is there any way to distinguish whether something in the north stimulates M.S. to occur, as opposed to something in the south inhibiting M.S. from developing? (Maybe some antigen increases self-tolerance, which seems to be a reason for lower % of asthma in children raised on farms or with dogs.) III) To the extent that the N-S difference is environmental, would that mean less of a genetic contribution to your probability of getting M.S.? * If so, then should there be any implications for the probability that a twin sister of an M.S. patient also getting M.S., depending on how far north they live? ** What if one identical twin were raised in North Carolina, but for some reason her twin was raised in New York, or raised in Canada? Although you can't expect to find 10,000 pairs of such twins, suppose they existed: and suppose that enough got M.S. so that it could be statistically significant to compare the percentages of twins who also got M.S. *** Is the "twin-ratio" a measure of how much the cause of M.S. is genetic, in contrast to the N-S ratio being a measure of how much the cause is environmental? Nobody seems to have considered this. IV) Do you suppose that diseases could be cured if professors and students and students thought more carefully about how to interpret the evidence that has already been found? V) When designing future research projects, how important is it that you already have considered as many as possible different alternative hypotheses. Is there any other way to design a good experiment except by considering at least two different theories, and figuring out something that one theory predicts should happen, and that the other theory predicts should not happen.
Do people always do this? Is it what you were taught about the scientific method in other courses? Is it what Warburg did? Or what his critics now do? These questions are meant as exercises to clarify, strengthen your thinking about autoimmunity. VI) What would it be like to be smarter than we are? How can pairs or groups of people be smarter than any one of them would be, by themselves? Can reasoning be made cumulative, so that it adds to itself?
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