Molecular Genetics
From Genetics Wiki
With methods of DNA sequencing and more complete understanding of the connections between DNA, RNA and proteins within the cell the field of molecular genetics appeared.
This field has a large degree of overlap with genetic engineering; however, I am trying to keep them distinct here with molecular genetics defined as an understanding of genetics on the molecular level and genetic engineering defined as the purposeful use of the understanding genetics to engineer traits (in a broad sense) into an organism.
Topics such as the physical structure of a gene and the structure of DNA fall within the field of molecular genetics.