The scientific study of heredity, and the environmental factors responsible for this, is known as genetics (from the Greek word genno = give birth).
Genetics can be divided into three areas:
1. Classical genetics: We concerned with mendal principle's, determination, linkage and cytogenetics.
2. Molecular genetics: Molecular genetics is the study of the genetic material, it's structure, replication and expression, as well as the information revolution emanating from the discoveries of recombinant DNA techniques.
3. Evolutionary genetics: Evolutionary genetics is the study of the mechanisms of evolutionary chance or changes in gene frequencies in populations.