The human genome is what makes us who we are as human beings. It is made up of about 3 billion different parts called nucleotides. (University of California Santa Cruz). Nucleotides are the units that make up DNA. A nucleotide is made up of 3 parts called a deoxyribose molecule, a phosphate group and a nitrogenous base. There are 4 types of bases in DNA: adenine, guanine, cytosine and thymine. DNA is found in the form of a double helix. (Miller and Levine) Humans have 23 pairs of chromosomes. You get 23 individual chromosomes from each parent that come together to form the 23 pairs that make you who you are. (See Shevick) DNA and RNA Sequencing Think of sequencing as decoding, but a genome is too long to decode all at once, so scientists choose small fragments of the genome and try to decode that small part. (The Genome News Network) After obtaining many parts, the next step is to put the decoded parts in the correct order. It's like a big puzzle or matching game that takes many years to solve. There are two different ways that scientists use to decode DNA. (The Genome News Network) The first is called the clone-by-clone method, and the other is called the whole-genome shotgun method. Clone by clone they cut the genome into about 150,000 base pairs or nucleotides, then use genome mapping to work out where each part should go. They then cut it into even smaller pieces, about 500 pairs, so they can work with it more easily and decode the information. The other method, the “shotgun” one, consists of breaking down the genome into much smaller parts, decoding them and putting them back together. The first way is much slower but more reliable where the rifle can be very fast but difficult to use. Both...... half of the document ......ct_scientific_failure_disease.html#Annas G. Who's afraid of the human genome?. National Forum [online serial]. nd;73(2):35. Available from: Science Reference Center, Ipswich, MA. Accessed March 2, 2014. Ascension Health Human Genome Project, accessed 2014-03-02 http://www.ascensionhealth.org/index.php?option=com_content&view=article&id=159&Itemid=172 National Human Genome Research Institute, ethical, legal and social implications (ELSI) Research accessed on 02-03-2014 http://www.genome.gov/10002229 Ethical, legal and social implications accessed on 02-03-2014 http://library.lanl.gov /cgi-bin/getfile?20- 11.pdfBiologists start human genome project. (1999). Great scientific achievements (p. 1093). Salem Press. Jennifer Welsh, What Cheap Genome Sequencing Means for the Future of Medicine, published September 7, 2012 at 9:57 2014-03-02