DNA and the genome

• Genome


  The entire genetic material of an organism
• Genetic material


  Includes all of the chromosomes, and the DNA found in the mitochondria
• Mitochondria contain their own DNA
• You always inherit your mitochondrial DNA from your mother because it comes from the mitochondria in the egg
• The human genome contains over 3 billion base pairs and almost 21000 genes that code for proteins
• The human genome has the ability to make many different proteins from the same gene by using it in different ways, or by switching part of a gene on or off
• Nucleus


  Inside the nucleus, four chromosomes are made up of long molecules deoxyribonucleic acid (DNA)
• DNA


  Long molecules made up of many repeating units
• Double helix structure


  DNA strands form a double helix structure
• Genes


  A small part of DNA where genetic information is stored
• Each gene codes for


  • A specific sequence of amino acids to make a specific protein
• Proteins


  Made from genes and include the enzymes that catalyse biochemistry
• Genes control proteins


  Proteins control the makeup of different specialized cells that form tissue which then form organ systems
• Helix


  The shape of DNA molecules
• Understanding the human genome helps us to understand inherited disorders such as cystic fibrosis and sickle cell disease
• The more we can understand what goes wrong in these diseases, the more chance we have of overcoming them either through medicines or by repairing the faulty genes
• There are genes that are linked to an increased risk of developing many diseases, from heart disease to type 2 diabetes
• Understanding the human genome is playing a massive part in the search for genes linked to different types of diseases
• The more we understand about the genome, the more likely we are to predict the risk for each individual, so they can make lifestyle choices to help reduce the risks
• This includes the changes that happen in the genome when a cancer develops
• By analysing the genomes of cancer cells, scientists and doctors hope to become even better at choosing the best treatment for each individual
• Understanding the human genome helps us understand human evolution and history
• People all over the world can be linked by patterns in their DNA, allowing scientists to trace human migration patterns from our ancient history
• We can also be linked to early members of the human family tree
• Most people have a small number of Neanderthal genes in their DNA, even though that branch of the human family died out around 40000 years ago