Genetics Overview


Genes contain the information that tells our bodies how to grow, develop and work. Genes are made up of DNA. Genes are passed from parents to children. We all have two copies of each gene in the cells of our bodies, one copy from each parent. Many illnesses are caused by inheriting faults in both copies of particular genes. These are known as autosomal recessive disorders.

Genes make proteins

Cells use the information in your genes to make proteins. Proteins do much of the work in your cells and your body as a whole. Some proteins give cells their shape and structure, others help cells carry out biological processes like digesting food or carrying oxygen in the blood.

Genetic variation

To make new cells, an existing cell divides in two. The first step a cell takes to divide is to copy the DNA so the new cells will each have a complete set of genetic instructions. Cells sometimes make mistakes during the copying process. Sometimes these mistakes are like typos and sometimes there are portions of a gene that are cut out or even duplicated. These variations can generate biological variation between people by causing differences in the recipes for proteins that are written in genes. Most of these variations have no effect on a person’s health, but some can cause disease.

How faults in genes cause disease

Variations in a gene that do cause disease often do so because the protein the gene produces is faulty and does not function as it should.

Types of genetic conditions

There are two types of genetic conditions relevant to these programs:

The function and purpose of the gene involved in each condition determines whether the condition is recessive or dominant.

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