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Pindara Private Hospital Magazine - Issue Ten

eoxyribonucleic acid or DNA is the building block of life. Every human is made up of cells containing DNA and a combination of a person’s entire DNA contained in their cells is their genome. In most cells, the genome is packaged into two sets of chromosomes: one from each parent. These are the genetic instructions which determine a person’s appearance, function and biology. Thinking about the population on the planet, it is easy to see how many variations and combinations can be expressed from DNA. Not only does this genetic code determine how a person looks and acts, but it can also determine disease in that individual. For over 15 years, scientists have been working on mapping the human genome to discover what each part of DNA controls. In 2003, the Human Genome Project published the final sequencing of the human DNA at a cost of three billion dollars. One by one, every base pair of the 3.3 billion chemical units (base-pairs) forming the human genome was revealed. This opened up a range of incredible opportunities in the field of molecular medicine and human evolution. The beginning of a huge new world of discoveries commenced. The first human genome did not belong to a specific individual donor but from a mix of a small group of European donors. Since then, studies of DNA variation have started in the international HapMap Project involving 270 individuals of different ethnic races. The DNA alphabet only contains four letters; A, C, G and T (Adenine, Cytosine, Guanine and Thymine). These letters form pairs. The sequence of these base pairs composes a book of six billion individual letters. As a comparison, the Encyclopaedia Britannica has 300 million letters. Imagine the task ahead; letters after letters is only the beginning, making sense of the words and the sentences (genes) is an even more enormous challenge. We have a huge book of six billion characters. Now we have to understand how these pages work together to create life, health and disease. Two years after the final sequencing, at a cost of over 270 million dollars, The Cancer Genome Atlas (TCGA) program was established to start unravelling the most common genetic alterations (mutations) of the 25 most common cancers. In cancer cells, small changes in the genetic letters can change what a genomic word or sentence means; these are mutations. For example, it can cause the cell to make a protein that doesn’t allow the cell to work as it should, such as making cells grow quickly and cause damage to surrounding cells. By studying the cancer genome, scientists are able to discover what letter changes cause a cell to become cancer. Since 2003, when the Cancer Genome Project started, the altered words (mutations) that contribute to the formation, growth and spreading of cancers have been found. Genes that protect the DNA (tumour suppressor genes) and genes that can cause cancer (oncogenes) have also been described. The genome of a cancer cell can also be used to tell one type of cancer from another. However, many mutations occur for a D pindaramagazine.com.au Pindara Magazine 35


Pindara Private Hospital Magazine - Issue Ten
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