Joe Carson queried:
>Given the Bibical story of man's creation, can there be more than four gene
>for any human characteristic? My armchair observation is that there seem to
>be no more than four types of eye, skin, and hair color, four blood types,
>four basic shapes of heads, etc.
Many human traits are coded for by large gene complexes. For example, human
blood group is coded for by at least twelve genes (F.B. Christiansen & M.W.
Feldman. 1986. Population Genetics. Blackwell Scientific. pp. 42-43.). Most
of these are comprised of only 2-4 alleles, but one (Rhesus) is comprised of
at least 10 alleles worldwide. I'm afraid I don't feel very qualified to
respond to the second half of your question, but perhaps someone else can
pick it up from here.
The world's first profession was natural resource manager.