Have you ever wondered why you look the way you do? This is because your genes are encoded with specific traits and functions! The human genome is the complete set of DNA sequences found in the 23 pairs of chromosomes, which are located in the nucleus of cells and act as the genetic code of an organism. The human nuclear genome is composed of three billion nucleotide base pairs that make up both the non-coding and protein-coding DNA regions, encoding 20 000 to 25 000 genes (Gonzaga-Jauregui et al., 2012). The Human Genome Project (HGP), which commenced in 1990, had three primary purposes: to produce a reference sequence of the entire human genome, map the location of all human genes, and make the data accessible. Prior to the HGP, there was little research completed on the structure of the human genome in its entirety and the genetic variations responsible for human disease (Hood & Rowen, 2013).
The HGP was successful in sequencing 95% of the gene-coding region with 99% accuracy (Little et al., 2003). This accomplishment enables future genetic research to be completed more precisely and quickly due to the freely accessible data. The human genome sequences do not represent any single individual’s genome, but rather act as a basis for comparison as all humans share the same set of genes that regulate their biological functions and developmental process. The sequencing of DNA helps with understanding biochemical defects/disease through applications such as the identification of mutations associated with various types of cancer and the construction of medication targeted to the genetic variations observed (Little et al., 2003).
A genetic disorder refers to a disorder caused by a deviance in the DNA sequence. This can involve a change in one or more genes, damage to the chromosomes themselves, or a mixture of non-genetic (i.e., lifestyle) and genetic factors (Sivam, 2012). Cystic Fibrosis (CF) is characterized by the production of thick, sticky mucus, digestive fluids, and sweat that clog passageways. This condition causes lung infections and pancreatic blockages that hinder the digestion process (Tolstoi & Smith, 1999). Improvements in the treatment of this condition can be attributed to advancements in the HGP.
CF is caused by mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene, which is the first gene to be studied using the HGP. Initially identified in 1989, the HGP led to the discovery of over 900 mutations in this gene (Tolstoi & Smith, 1999). The most common mutation of the CF gene is the deletion of 3 base-pairs, resulting in the loss of a phenylalanine amino acid. Normally, the CFTR protein functions as an ion channel that is responsible for the release of chloride ions, maintaining salt balance. With CF, chloride ions cannot be pumped out of the cell, causing extremely viscous mucus (Tolstoi & Smith, 1999). Through the HGP, researchers aim to cure CF through correcting the defective gene or resulting protein. Researchers are working towards using the HGP to understand all of the human genome data that has been collected to study how genes contribute to healthy physiology by comparing this data with genetic variations to understand disease biology (Gonzaga-Jauregui et al., 2012). New methods are projected to diagnose and treat diseases through biotechnological applications, such as gene-editing (Little et al., 2003).
Gonzaga-Jauregui, C., Lupski, J. R., & Gibbs, R. A. (2012). Human Genome Sequencing in Health and Disease. Annual Review of Medicine, 63(1), 35–61. doi: 10.1146/annurev-med-051010-162644
Hood, L., & Rowen, L. (2013). The human genome project: big science transforms biology and medicine. Genome Medicine, 5(9), 79. doi: 10.1186/gm483
Little, J., Khoury, M., Bradley, L., Clyne, M., Gwinn, M., Lin, B., & Lindegrin, M. (2003). The Human Genome Project Is Complete. American Journal of Epidemiology, 157(8), 667–673. doi: 10.1093/aje/kwg048
Sivam, V. (2012). Has the Human Genome Project Delivered for Healthcare? Annals of Medicine and Surgery, 1, 19–20. doi: 10.1016/s2049-0801(12)70006-7
Tolstoi, L. G., & Smith, C. L. (1999). Human Genome Project and Cystic Fibrosis—a Symbiotic Relationship. Journal of the American Dietetic Association, 99(11), 1421–1427. doi: 10.1016/s0002-8223(99)00343-0