Overview of Molecular Biology

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In 1970 Francis Crick published a paper in the science journal Nature on the central dogma of molecular biology, presenting the normal flow of genetic information, as shown in Figure 1 (Crick, 1970). Although many discoveries have been made since then, the main idea still stands: every organism uses its own DNA sequence to synthesize its proteins (Crick, 1970). In order to function properly, the genome has to be kept unblemished, any damage can potentially affect a protein’s structure, interfering with its function (Brown, 2010). Albeit evolution has equipped every functional cell with a molecular toolkit designed to repair and thus prevent DNA damage, errors still occur. Those errors that remain buried within a cell’s genome and are sometimes passed on to the next generation, go under the name of DNA mutation. Because DNA codes for proteins and RNA molecules, almost every change in the DNA sequence, left unrepaired, can cause physiological malfunctions, known as genetic diseases. According to The Global Genes Project, there are more than 7,000 rare genetic diseases alone. Despite those alarming figures, genetic diseases are not uncommon since DNA is rather a fragile molecule prone to damage. Many types of mutations have been analyzed and classified, the simplest of which is point mutation. The change of one base pair into another has been linked to life-threatening diseases such as sickle cell anemia. In sickle cell anemia, the structure of the β-strand of the hemoglobin protein has been modified by the replacement of glutamine acid (Ingram, 1957).At the molecular level, the change from glutamic to valine corresponds to a modification of adenine to thymine (Marotta et al., 1977), leaving the peptide chain with a loss of negative... ... middle of paper ... ...e mitochondria and possible contribution to mutagenesis through reduced replication fidelity. Proceedings of the National Academy of Sciences 102, 4990-4995 22. Taylor, R. W., & Turnbull, D. M. (2005) Mitochondrial DNA mutations in human disease. Nature Reviews Genetics 6, 389-402 23. Thibodeau P. H., et al., (2010). The cystic fibrosis-causing mutation deltaF508 affects multiple steps in cystic fibrosis transmembrane conductance regulator biogenesis. J. Biol. Chem.285, 35825–35835 24. Transtutors.com. 2014. Gene Abnormalities and Disorders Help for Chromosomes - Transtutors. [online] Available at: http://www.transtutors.com/homework-help/biology/chromosomes-genetic-disorder/gene-abnormalities-and-disorders.aspx [Accessed: 21 Mar 2014]. 25. Viguera, E., et al. Replication slippage involves DNA polymerase pausing and dissociation. EMBO Journal 20, 2587–2595 (2001)
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