What is genetics?
It has long been known that some families are more likely than others to suffer from a particular illness. This includes mental disorders like depression and schizophrenia.
During the 19th century scientists became more and more convinced that mental illnesses were due primarily to hereditary factors.
Is depression a hereditary disorder?
One method of assessing heredity was to compare twins and look at the psychological development of adopted children. This allowed them to gauge just how big an impact our genes and environment have when it comes to mental illness.
The early 1960s brought collaboration between researchers in the USA and Denmark involving a series of genetic studies of twins and adopted children.
This collaboration developed into a very rewarding project, proving beyond doubt that genetic factors play a role in both:
- Schizophrenia and
- Manic-depressive/ Bipolar Disorder
Today we also use molecular-genetic methods. The more we learn about the human gene pool, the more we learn about the importance of genes in both mental and physical illness.
What is a cell?
We all start out as a single cell - an egg cell, which starts to multiply by division as soon as it has been fertilised with a sperm cell. Once the cells have divided a number of times, some of them begin to specialize and become:
- Skin cells
- Muscle cells
- Nerve cells, etc.
Eventually they form a fetus and we are born into the world. Our cells keep on dividing as we grow, and most types of cell carry on dividing throughout our lives.
Each cell is a tiny organism equipped to:
- Divide
- Survive
- Carry out its special functions
Each cell has small organs called organelles that generate energy, transport chemicals and so on. Each cell also contains a nucleus that, among other things, contains the chromosomes. The chromosomes in turn contain our genes - in other words, they contain information about how we develop and function, much like the information in a computer database.
What do we know about genes today
Today we define a gene as follows:
- A piece of a DNA molecule that contains the genetic code for a particular protein.