Tetranucleotide hypothesis

The tetranucleotide hypothesis of Phoebus Levene[1] proposed that DNA was composed of repeating sequences of four nucleotides.

[3] In 1940, at the time of Levene's death, Bass wrote in his obituary[4] As a result of Levene’s work we have an exact concept of the structures of these huge molecules, probably the most complex biological materials whose architectural picture has been reconstructed.In that form there is an implication that the four bases are present in equal amounts in DNA, and small variations in the experimental values were assumed to be the result of experimental error.

meant that DNA could not have a systematic repetition of a fundamental unit, as required by the tetranucleotide hypothesis.

In later years some authorities considered the tetranucleotide hypothesis to have been harmful to the development of molecular biology.

[6] More recently, Hargittai[7] saw it in a more positive light, and Frixione and Ruiz-Zamarripa[8] wrote as follows: [Levene's] work was to culminate in Levene and Tipson’s 1935 report showing accurately for the first time the actual molecular structure of DNA, as well as a nearly correct depiction of the RNA structure.