Finding New Facts About Genetic Mutation SeRa Kim What is Genetic Mutation? In biology, mutations are changes to the genetic material (usually DNA or RNA). Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals (mutagens), or viruses, or can occur deliberately under cellular control during processes such as meiosis or hypermutation. Types of Mutations Single base substitutions Insertions and deletions Chromosomal mutations Single Base Substitutions A single nucleotide base becomes replaced by another. These single base changes are also called point mutations. • Insertions and deletions Extra base pairs may be added or deleted from the DNA of a gene. Chromosomal mutations Translocations - Translocations are the transfer of a piece of one chromosome to a non-homologous Inversion - A region of DNA on the chromosome can flip its orientation with respect to the rest of the chromosome. Deletions - A large section of a chromosome can be deleted resulting in the loss of a number of genes. Duplications - In this mutation, some genes are duplicated and displayed twice on the same chromosome. Chromosome non-disjunction - During cell division, the chromosomes fail to successfully separate to opposite poles, resulting in one of the daughter cells having an extra chromosome and the other daughter cell lacking one. Cystic Fibrosis Cystic fibrosis (CF) is a disease that causes the body to make thick, sticky mucus (say: myoo-kus). This causes problems in two major areas: the lungs and the digestive system. mucus plug in appendix Down Syndrome Down syndrome or trisomy 21 is a genetic condition resulting from the presence of all or part of an extra 21st chromosome. Down syndrome is characterized by a combination of major and minor abnormalities of body structure and function. Among features present in nearly all cases are impairment of learning and physical growth, and a recognizable facial appearance usually identified at birth. It is named after John Langdon Down, the British doctor who first described it in 1866. DS is the commonest chromosomal anomaly with an incidence of about 1:700 live births.It includes a phenotype with mental retardation; characteristic facies with oblique eye fissure, epicanthus, flat nasal bridge, protruding tongue (figs 1a and 1b); short broad hands and wide space between first and second toes (figs 2 and 3); hypotonia and other associated congenital anomalies and developmental disorders. Haemophilia Haemophilia or hemophilia is the name of any of several hereditary genetic illnesses that impair the body's ability to control bleeding. Genetic deficiencies (or, very rarely, an autoimmune disorder) cause lowered plasma clotting factor activity so as to compromise blood-clotting; when a blood vessel is injured, a scab will not form and the vessel can continue to bleed excessively for a very long period of time. The bleeding can be external, if the skin is broken by a scrape, cut or abrasion, or it can be internal, into muscles, joints or hollow organs. It might therefore present visibly as skin bruises, or subtly as melena, hematuria, or bleeding in the brain. Huntington’s Disease Huntington's disease (HD, also Huntington disease), formerly known as Huntington's chorea, is a rare inherited genetic disorder characterized by abnormal body movements called chorea, and a reduction of various mental abilities. It takes its name from the Ohio physician George Huntington who described it precisely in 1872. Cross section of a brain of an adult with Huntington disease, illustrating marked striatal atrophy.
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