towards an analysis of errors made by university students ... - DSpace

few genes, if any, are confined in a race, in general the more
distant populations are from each other, the more
distinctive
are their characteristics. Between these, people of Central and
South Africa and the Caucasians of Scandinavia are examples of
extremes. They resemble the intervening Semitic peoples
surrounding the Mediterranean. Such genetic diversity is a
biological asset that has nothing to do with ideas about racial
'superiority', or 'inferiority'. A species whose genetic
constitutions have altered when environment changes as has
happened to the human species, is more likely to
survive.
The variant «in susceptibility to disease that is
part of the ethnic variation is best illustrated by diseases
that affect the blood (which is easy to study by chemicalmicroscopic
methods). Sickle-cell anemia, for example, which
provides protection against malaria,
is virtually confined to
peoples of the east, west and Central African origin, and to
isolated places in India. Mediterranean peoples suffer from
thalassemia, another hereditary form of anemia, that seems,
like
sickle-cell anemia, to protect people from malaria.
No such ready explanation can be found for
contrasts
in susceptibility of Rh sensitization between peoples of the
north and those of Africa and Asia. Among Europeans, 15 per
cent of the population have Rh-negative blood; among
South
African negroes only 5%; among Chinese and Japanese only 2%.
Because the components of the Rh-negative factors are combined
differently
in the blood of European mothers, the risk of anemia
resulting from Rh sensitization is even greater for European
children than the high proportion of the Rh-negative blood