rising@utzoo.uucp (Jim Rising) (02/13/89)
Some information about Tay-Sach's disease from Bodmer & Cavalli-Sforza, Genetics, Evolution, and Man (1976) that probably isn't as up to date as it could be. They say that the "incidence of TSD among Ashkenazi Jews (whose ancestors originated in Eastern Europe) is about 1 in 4,000, while that among other Jews or non-Jews is some 100 times smaller (p. 360)." They go on to say..."it is unlikely that rates of mutation ... differ in different populations. One possibility is random genetic drift. The mutant allele may simply be one that has happened to increase in frequency, by chance, in a given population...". "It has been suggested that heterozygotes for Tay-Sachs disease are more resistant to tuberculosis, which was an especially frequent disease in the crowded ghettos of Northeast Europe, but this is highly speculative. A direct search for heterozygote advantage in Tay-Sachs disease has so far given inconclusive results." I have further been told that the high incidence of TSD is not a not a general characteristic of Eastern European Jews, but rather specific to a limited region of Poland--perhaps even a single town. A lot of people from this region immigrated to the Toronto area. I don't have solid confirmation of this, but if there is interest I'll try to get more information. --Jim Rising -- Name: Jim Rising Mail: Dept. Zoology, Univ. Toronto, Toronto, Ontario, Canada M5S 1A1 UUCP: uunet!attcan!utzoo!rising BITNET: rising@utzoo.utoronto.bitnet