Lynn Margulis attended the University of Chicago, earned a master's degree in Biological Sciences from the University of Wisconsin-Madison in 1960, and received her Ph.D. in 1963 in the faculty of Biological Sciences from UC Berkeley in Botany. In 1966, as a young faculty member at Boston University, she wrote a theoretical paper titled "On the Origin of Mitosing Cells".[4] The paper however was "rejected by about fifteen scientific journals," Margulis recalled.[5] It was finally accepted by Journal of Theoretical Biology and is considered today a landmark in modern endosymbiotic theory. Although it draws heavily on symbiosis ideas first put forward by mid-19th century scientists and by Merezhkovsky (1905) and Ivan Wallin (1920) in the early-20th century, Margulis's endosymbiotic theory formulation is the first to rely on direct microbiological observations (as opposed to paleontological or zoological observations which were previously the norm for new works in evolutionary biology). Weathering constant criticism of her ideas for decades, Margulis is famous for her tenacity in pushing her theory forward, despite the opposition she faced at the time.
The underlying theme of endosymbiosis theory, as formulated in 1966, was interdependence and cooperative existence of multiple prokaryotic organisms; one organism engulfed another, yet both survived and eventually evolved over millions of years into eukaryotic cells. Her 1970 book, Origin of Eukaryotic Cells, discusses her early work pertaining to this organelle genesis theory in detail. Currently, her endosymbiosis theory is recognized as the key method by which some organelles have arisen (see endosymbiotic theory for a discussion) and is widely accepted by mainstream scientists. The endosymbiosis theory of organogenesis gained strong support in the 1980s, when the genetic material of mitochondria and chloroplasts was found to be different from that of the symbiont's nuclear DNA.[6]
In 1995, prominent evolutionary biologist Richard Dawkins had this to say about Lynn Margulis and her work: