Population Genetics

2021 Words Mar 31st, 2013 9 Pages
In 1831, Charles Darwin, proposed a theory of evolution occurring by the process of natural selection. This has come to be known as the Theory of Natural Selection. Darwin worked on his theory for 20 years and after learning that Alfred Russel Wallace, another naturalist, had developed similar ideas, the two made a joint announcement of their discovery in 1858. Darwin published 'On the Origin of Species by Means of Natural Selection' in 1859, 28 years after he proposed his theory of natural selection. [1]
Darwin’s theory of natural selection states that evolutionary change comes through the production of variation in each generation and differential survival of individuals with different combinations of these variable characters. [2]
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A definitive description of Huntington’s Chorea occurred, when George Huntington submitted his article 'On chorea' to the Medical and Surgical Reporter of Philadelphia, USA, in 1872, 31 years after Waters gave his description of the disorder. Waters ' described a disorder 'which is markedly hereditary, very rarely makes its appearance before adult life, in all cases induces a state of more or less perfect dementia and never ceases while life lasts'. The disease was recorded early on by observers; however Waters’ description was the first detailed description of the disease. It is believed that the disease was present among the population at a much earlier date as it is caused by a dominant allele. Because of its long history, and the fact that the mutation rate for Huntington's chorea is among the lowest recorded for any inherited condition, the disease has great potential in genealogical investigations. The Afrikaner population posed as a great source to study the disease because of the excellent recording of the origins and history of the Afrikaner nation. The excellent documentation facilitated efforts to trace the disease back to the earliest transmission of the gene to South Africa.
In their research they found that the only previous attempt to investigate the genealogy of this disease in