Lynn Margulis
Every science needs its revolutionary thinkers, for today’s outlandish ideas become tomorrow’s textbook orthodoxy. There were few as revolutionary as Lynn Margulis, whose ideas about symbiogenesis, initially dismissed as crazy, are now the cornerstone of modern biological thought. Born to a large Jewish family in Chicago, the fiery and precocious Lynn entered the University of Chicago aged just 16, and her first academic paper, on the genetics of the protist Euglena, was published when she was 20. Her notoriety began in 1966 with a paper on the origin of eukaryotic cells, which she suggested had evolved from associations of bacteria. Sheproposed that the organelles of cells, such as chloroplasts and mitochondria, evolved as separate organisms but became assimilated into a new kind of organism, the eukaryotic cell. It was more than a decade before her ideas were substantiated by significant experimental evidence, and we now know that they are largely correct. It turns out that chloroplasts – small, green bodies in plant cells in which photosynthesis takes place – have their own DNA, revealing that they were once descended from cyanobacteria (once called blue-green algae). Mitochondria, for their part, are small bodies that generate much of the energy required by cells; they also have their own DNA, and are distantly related to bacteria called proteobacteria. Like many people with controversial ideas, Margulis did not stop there. With James Lovelock (born in 1919) she became a vocal proponent of the ‘Gaia’ hypothesis that the Earth is a single, self-regulating system, and, more controversially, she contended that the humanimmunodeficiency virus (HIV-1) was not a cause of AIDS (Acquired Immune Deficiency Syndrome). She married and divorced twice, and later reportedly said that it was not humanly possible to be a first-class scientist, wife and mother all at the same time.
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