![]() ![]() Using a deli napkin for paper, a small group of scientists including Stanley Falkow, Stanley Cohen, Herbert Boyer, and Charles Brinton concocted a wild idea of using the newly discovered EcoRI enzyme (and its predictable cut site) to develop the first plasmid “cloning” experiment. Prior to this, bacteriophage, especially lambda, was the tool of choice for molecular biologists wanting to study bacterial genetics. This all changed thanks, in part, to a collaboration initiated at a Hawaiian deli in 1972. Thus the term “episome” was eventually dropped and we’ve been using "plasmid" ever since!Īlthough discovered in the early 1950s, it took until the 1970s for plasmids to gain prominence in the scientific community. ![]() Like F-factors, R-factors could be transferred between bacteria via cell-to-cell contact however, scientists noted that, unlike F-factors, the evidence did not support the idea that R-factors could integrate into the chromosome. This terminology held until the 1960s when scientists began to study other extrachromosomal particles, particularly Resistance or R-factors. At the time, the use of episome seemed appropriate, especially since the Fertility, or F-factor discovered by Ester Lederberg in 1952 was noted to integrate into the E. ![]() His proposal, however, was basically ignored. A separate term, “episome”, defined as “a non-essential genetic element which could exist either autonomously or integrated into the chromosome” was proposed a few years later by Élie Jacob and François Wollman and became the widely adopted name for these elements. He proposed the catch-all term “plasmid” derived as a hybrid of "cytoplasm" and "id" (Latin for 'it'), as “a generic term for any extrachromsomal hereditary determinant”. In 1952, Joshua Lederberg set out to clarify the classification of these cytoplasmic inheritance factors. At the time, these extranuclear agents of heredity were thought of as everything from parasites, to symbionts, to genes and the labels applied to them were vague or contradictory, owing in part to the fact that very little was known about the role these factors played within an organism. Bioblasts? Plasmagenes? In the 1940s and 50s, scientists were working to understand genetic cytoplasmic factors that could be transferred between cells. ![]()
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