Population genetics is the mathematical investigation of the changes in
the genetic structure of populations brought about by selection,
mutation, inbreeding, migration, and other phenomena, together with
those random changes deriving from chance events. These changes are the
basic components of evolutionary progress, and an understanding of their
effect is therefore necessary for an informed discussion of the reasons
for and nature of evolution. It would, however, be wrong to pretend that
a mathematical theory, depending as it must on a large number of
simplifying assump- tions, should be accepted unreservedly and that its
conclusions should be accepted uncritically. No-one would pretend that
in the event of disagreement between observation and mathematical
prediction, the discrepancy is due to anything other than the inadequacy
of the mathematical treatment. The biological world is, of course, far
too complex for the study of population genetics to be simply a branch
of applied mathematics, so that while we are concerned here with the
mathematical theory, I have tried to indicate which of our results
should continue to apply in a context wider than that in which they are
formally derived. The difficulties involved in the joint discussions of
mathematical and genetical problems are obvious enough. I have tried to
aim this book rather more at the mathematician than at the geneticist,
and for this reason a brief glossary of common genetical terms is
included.
