Detail map of Washington, District of Columbia, United States,Philadelphia, Pennsylvania, United States Overview map of Washington, District of Columbia, United States,Philadelphia, Pennsylvania, United States

A: Washington, District of Columbia, United States, B: Philadelphia, Pennsylvania, United States

Reichert & Brown Publish the First Large-Scale Investigation of Species Differences at the Molecular Level


In 1909 American scientists Edward Tyson Reichert and Amos Peaslee Brown published from the Carnegie Institution (now Carnegie Institution for Science) in Washington, D.C. The Differentiation and Specificity of Corresponding Proteins and other Vital Substances in Relation to Biological Classification and Organic Evolution: The Crystallography of Hemoglobins

This massive work with 100 plates including 600 images, was the first large-scale investigation of species differences at the molecular level.

“In 1909 appeared an extraordinary volume, The Crystallography of Hemoglobins, by Edward Tyson Reichert, a physiologist at the University of Pennsylvania, and Amos Peaslee Brown, a mineralogist there. Reichert had conceived the ambition to plot the evolutionary relationships among species by the divergences among their protein molecules. His essential idea was merely seventy years ahead of the technology: only with the advent of Frederick Sanger’s methods for sequencing amino acids could students of evolution begin to measure the similarities among proteins, and only with Sanger’s means of sequencing nucleotides in DNA, beginning in 1976, could such measurements of genetic similarity begin to be accurate. But Reichert understood the enormous scope for diversity if proteins were large, specific molecules; he settled on crystal forms—and recruited his colleague Brown—as the means to get at degrees of difference, and on hemoglobin as the easily crystallized protein universal among animals. Their book surveyed the nineteenth-century literature of hemoglobin; catalogued crystals of the stuff from a hundred and nine different vertebrate species—Philadelphia had a good zoo—complete with drawings and measurements of the crystal forms; and ended with six hundred large, clear, well-printed photomicrographs of hemoglobin crystals” (Judson, The Eighth Day of Creation, p. 492).

“Physiologist Edward Reichert of the Carnegie Institution of Washington proposed in 1909 that if a definite relationship between differences in proteins and physiological differences between species could be demonstrated, then ‘a fundamental principle of the utmost importance would be established in the explanation of heredity, mutation, the influence of food and environment, the differentiation of sex, and other great problems of biology, normal and pathological.’ Reichert, together with Amos Brown, examined hemoglobin crystals from about two hundred mammalian species, establishing a taxonomy of hemoglobins that paralleled traditional organismic classification. Mammalian visible attributes were thus replaced by the properties hidden in their molecular structures. Specificity therefore served as a probe into evolutionary change . . .” (Kay, Who Wrote the Book of Life, pp. 43-44). 

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