Thursday, January 17, 2008

The death of the dichotomy?

From the AP, on page D3: a news item (subscription required) concerning genetics. Apparently, there is not just one gene that necessarily causes a disease, but rather several (as one might infer from the concepts of incomplete- and co-dominance in Mendelian genetics). In particular, scientists claim that a five-gene combination is the chief cause of prostate cancer.

There are a few drawbacks:

  • These results have, so far, been confirmed only in Sweden.
  • Also, "the markers do not help doctors tell which cancers need treatment and which do not -- they turned out to have nothing to do with the aggressiveness of a tumor, only whether a man is likely to develop one."
  • Related to the first reason, "Sweden was chosen because the population is so ethnically similar and well suited to gene studies."
Another one, added 1/22/08 (D2, Marilyn Chase, subscription required): two genes have been discovered that contribute to lupus. The first, BLK, likely influences B cells, a type of white blood cell. The second, ITGAM, probably affects T cells, another kind. Scientists expect at least 10 genes to influence lupus overall--perhaps even 20 or 30.

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