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The tetranucleotide hypothesis of Phoebus Levene [1] proposed that DNA was composed of repeating sequences of four nucleotides. [2] It was very influential for three decades, and was developed by Levene at least into the 1910, and the diagram at the right illustrates the view of Levene and Tipson. [3] In 1940, at the time of Levene's death ...
Phoebus Aaron Theodore Levene (25 February 1869 – 6 September 1940) was a Russian-born American biochemist who studied the structure and function of nucleic acids. He characterized the different forms of nucleic acid, DNA from RNA , and found that DNA contained adenine , guanine , thymine , cytosine , deoxyribose , and a phosphate group.
Erwin Chargaff (11 August 1905 – 20 June 2002) was an Austro-Hungarian-born American biochemist, writer, and professor of biochemistry at Columbia University medical school. [1] A Bucovinian Jew who emigrated to the United States during the Nazi regime, he penned a well-reviewed [2][3] autobiography, Heraclitean Fire: Sketches from a Life ...
Levene's test. In statistics, Levene's test is an inferential statistic used to assess the equality of variances for a variable calculated for two or more groups. [1] This test is used because some common statistical procedures assume that variances of the populations from which different samples are drawn are equal.
Hershey–Chase experiment. The Hershey–Chase experiments were a series of experiments conducted in 1952 [1] by Alfred Hershey and Martha Chase that helped to confirm that DNA is genetic material. While DNA had been known to biologists since 1869, [2] many scientists still assumed at the time that proteins carried the information for ...
William Kruskal. Bonnie Ray. Howard Levene (January 17, 1914 – July 2, 2003) [1] was an American statistician and geneticist. He received his Ph.D. from Columbia University in 1947, and joined the faculty there shortly thereafter. He remained on the faculty at Columbia, where he served as professor of mathematical statistics and genetics ...
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as genocide, speciocide, widespread violence or intentional culling. Such events can reduce the variation in the gene pool of a ...
[191] [192] [193] In 1929, Levene identified deoxyribose sugar in "thymus nucleic acid" (DNA). [194] Levene suggested that DNA consisted of a string of four nucleotide units linked together through the phosphate groups ("tetranucleotide hypothesis"). Levene thought the chain was short and the bases repeated in a fixed order.