  In this the first of an anticipated four paper series, fundamental results of
quantitative genetics are presented from a first principles approach. While
none of these results are in any sense new, they are presented in extended
detail to precisely distinguish between definition and assumption, with a
further emphasis on distinguishing quantities from their usual approximations.
Terminology frequently encountered in the field of human genetic disease
studies will be defined in terms of their quantitive genetics form. Methods for
estimation of both quantitative genetics and the related human genetics
quantities will be demonstrated. While practitioners in the field of human
quantitative disease studies may find this work pedantic in detail, the
principle target audience for this work is trainees reasonably familiar with
population genetics theory, but with less experience in its application to
human disease studies. We introduce much of this formalism because in later
papers in this series, we demonstrate that common areas of confusion in human
disease studies can be resolved be appealing directly to these formal
definitions. The second paper in this series will discuss polygenic risk
scores. The third paper will concern the question of "missing" heritability and
the role interactions may play. The fourth paper will discuss sexually
dimorphic disease and the potential role of the X chromosome.
