The Expanded Self: Society as Self 277“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanityskin, a factor needed for calcium absorption). Apparently, in the north-
ern hemisphere where sunlight is deficient, people with the lactase gene
are able to enjoy the benefit of cow milk. They live healthier and longer
lives and have a better chance for procreation. Here, a gene has been
selected by the culture of animal domestication.^34
Another instance of culture affecting the genome is the case of
sickle cell anemia. Sickle cell anemia is a disease when a person car-
ries two copies (homozygous) of the mutated gene. But when a person
has only one copy (heterozygous), he not only does not manifest sickle
cell disease (a carrier) but also is resistant to malarial infection. There-
fore, in a place where malaria is endemic, a carrier of the sickle cell
gene lives longer. In Africa, malaria is rampant in places where mosquito
breeding grounds are abundant in the form of stagnant water ponds,
which frequently are an outcome of excessive deforestation. Therefore,
a human practice (cutting down trees) becomes a selective force for the
perpetuation of a gene (the sickle cell gene). Other examples include
the alteration of human gut size since the invention of fire and cooking
two million years ago,^35 and the higher alcohol tolerance of Europeans
relative to Asians following greater alcohol consumption in Europe.^36
In short, the controversy over nature versus nurture is resolved if we
consider evolution as multidimensional, that it is not only a matter of
genetics but also epigenetics, the latter encompassing culture as one of
the determinants.37,38
12.6.11 Common external threats (real or imaginary)
Social cohesion can be fostered strongly, sometimes rapidly, in the face
of an external threat to a society’s existence, such as an attack by a for-
eign nation. History shows that crafty rulers frequently fabricate outside
threats as a ploy to restore their failed governing power. One of the most
glaring examples of unity against a common threat was the engineering of
the first crusade by Pope Urban II in 1095. In a most rousing and enticing
speech against a backdrop of internal fractionation and disunity, the Pope