Three Major Fields of Genetics
Mostly, the study of genetics can be divided into three major fields:
- Transmission genetics,
- Molecular genetics, and
- Population genetics.
Also known as classical genetics, transmission genetics studies the basic principles of genetics and researches how traits are passed from one generation to the next. Major topics addressed in this area are:
- The relation between chromosomes and heredity,
- The arrangement of genes on the chromosomes, and
- Gene mapping (finding out and describing where certain genes can be found on the chromosomes).
The focus of this field is the individual organism. It considers how a certain organism inherits its genetic makeup and how it passes on genes to its descendants.
Molecular genetics focuses on the chemical nature of the genes themselves. Some topics covered by this field in genetics are:
- How genetic information is encoded, replicated and processed,
- The cellular processes of replication, transcription and translation (for more information on these processes: see From DNA to Protein), and
- Gene regulation, the process that controls the expression of genetic information.
In this field the scale on which is focused is that of the gene itself, on its structure, organization and function.
Population genetics is the field of genetics that explores the genetic composition of groups of individual members of (mostly) the same species. The main area that is covered by this field, is:
- How the genetic composition of a group changes over time.
The focus of population genetics lies primarily on (part of) the group of genes found in a population.
Other Fields and Combinations
This division is a relatively traditional one, and it is convenient to divide the study of genetics in these three fields, but it is important to recognize that these fields overlap and that each of the above fields can be further divided into more specialized fields. Examples of this are:
- Chromosomal genetics,
- Biochemical genetics,
- Quantitative genetics.
And many more fields exist. An alternative division of genetics can be based on the organism under consideration (popular study organisms are the fruit fly, corn or bacteria), and each of these organism can be studied on a transmission, molecular or population level.
It may be clear that modern genetics is a very broad field, which can be divided in several alternative ways, leading to several closely interrelated sub-disciplines and specializations. And many genetic research projects often combine different aspects of genetics to reveal new knowledge, emphasizing the complexity of the field.