The study of the influence of genes on development is the study of nature (heredity) as opposed to nurture (environment).

Nature

The processes within an organism that guide that organism to develop according to its genetic code.

Nurture

The processes external to an organism that nourish it as it develops according to its genetic code or that cause it to swerve from its genetically programmed course. Environmental factors that influence development.

Genes

Fundamental units of heredity that are responsible for guiding the process of creating proteins that, in turn, play critical roles in body functions and development.