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About | Classical Genetics | Timelines | What's New | What's Hot

About | Classical Genetics | Timelines | What's New | What's Hot


ESP Digital Book

The Mechanism of Mendelian Heredity

T. H. Morgan

A. H. Sturtevant

H. J. Muller

C. B. Bridges


Thomas Hunt Morgan was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University, Morgan and his team demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics.


Alfred H. Sturtevant was a key member of T. H. Morgan's "Fly Room" team at Columbia University. This group proved that genes are real objects, carried on chromosomes. While still an undergraduate, Sturtevant showed that the relative location of genes could be measured and he produced the first genetic map of a chromosome.


Hermann Joseph Muller (or H. J. Muller) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (Mutagenesis) as well as his outspoken political beliefs. Muller frequently warned of the long-term dangers of radioactive fallout from nuclear war and nuclear testing, helping to raise public awareness in this area. At 16 he entered Columbia College. From his first semester he was interested in biology. He became an early convert of the Mendelian-chromosome theory of heredity and to the concept of genetic mutations and natural selection as the basis for evolution.


Calvin Blackman Bridges was an American scientist, known for his contributions to the field of genetics. Along with Alfred Sturtevant and H.J. Muller, Bridges was part of the famous fly room of Thomas Hunt Morgan at Columbia University. Tragically, Calvin's mother died when he was two years old, and his father died a year after his mother's death, leaving Calvin Bridges an orphan. Following the death of his parents, Bridges was taken in and raised by his grandmother. Despite now being known in the scientific world as one of the most influential researchers regarding Drosophila melanogaster, it took Bridges several years to complete high school, graduating when he was 20 years old. However, despite this setback, Bridges moved on to be an outstanding student at Columbia University, which he attended both for undergraduate and postgraduate school. While taking a zoology class, Bridges met Thomas Hunt Morgan. This started a relationship which would lead to many important discoveries regarding genetics and evolution.

Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin and even a collection of poetry — Chicago Poems by Carl Sandburg.


ESP now offers a large collection of user-selected side-by-side timelines (e.g., all science vs. all other categories, or arts and culture vs. world history), designed to provide a comparative context for appreciating world events.


Biographical information about many key scientists (e.g., Walter Sutton).

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are automatically maintained and generated on the ESP site.

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