What history tells us XIX. The notion of the episome

  title={What history tells us XIX. The notion of the episome},
  author={Michel Morange},
  journal={Journal of Biosciences},
  • M. Morange
  • Published 30 November 2009
  • Biology
  • Journal of Biosciences
Modern textbooks of biology and molecular biology describe episomes only briefl y or not at all. Plasmids receive much more attention. The notion of episome was fi rst introduced in a publication of the French Academy of Science by François Jacob and Elie Wollman in 1958 (Jacob and Wollman 1958): episomes “may or may not be present in a cell, and when present they may be either autonomous or integrated” (in the chromosome) (Jacob and Wollman 1958). Episomes were more precisely described in… 

What history tells us XXXI. The replicon model: Between molecular biology and molecular cell biology

The replicon model was a first and significant step from molecular biology to molecular cell biology, as well as a decisive moment in the scientific career of Jacob and was deeply anchored in the previous work of the Pasteurian group.

History of science is good for you

The editorial raises a tremendously important issue — namely the relevance of science’s past for its present productivity — but in the opinion it narrows the problem to one of accessing publications in the digital age, and encourages microbiologists to engage more extensively with historical literature.



Plasmid (1952-1997).

The bedrock of genetic mechanism is no longer mitosis and meiosis of chromosomes; it is template-directed DNA assembly, which is often more readily studied and managed with the use of plasmids, which replicate autonomously outside the chromosomes.

Hybridizing bacteria, crossing methods, cross-checking arguments: the transition from episomes to plasmids (1961-1969).

  • M. Grote
  • Biology
    History and philosophy of the life sciences
  • 2008
This paper analyzes the transition from the episome to a renewed plasmid concept both on the experimental and the conceptual level and indicates a gradual transition of molecular biology from its early "analytic" to the "synthetic" phase of genetic engineering.

Cell genetics and hereditary symbiosis.

This review is an attempt to reconcile the attitudes that plasmids are symbiotic organisms, and that they comprise part of the genetic determination of the organic whole, in organisms whose germ and soma are not irreversibly differentiated.

Genetic Studies of Lysogenicity in Escherichia Coli.

ECENT research on Escherichia coli phages has outlined the biology of R viruses that promptly lyse their bacterial hosts (DELBRUCK 1950). In addition to the progressive parasitic relationship that

What history tells us XIII. Fifty years of the Central Dogma

The 50th anniversary offers an excellent opportunity to reconsider the Central Dogma, what it did and did not assert, what exactly Crick said, the context in which it was proposed, the challenges it has faced and overcome or failed to overcome since its inception, and the roots of its legitimacy.

Terminology of Enzyme Formation

‘enzymatic adaptation’ should denote a modification of enzymatic constitution which increases fitness, irrespective of whether it involves genotypic or phenotypic change, and microbiologists have in fact often used it in this broader sense.

What history tells us III. André Lwoff: From protozoology to molecular definition of viruses

The different phases of Lwoff's work are described, some of its features are outlined, and the continuities behind its apparently eclectic nature are underlined.

What history tells us

The present series aims to give historical glimpses that bear on contemporary biology, the hope is that these glimpses will be both a source of inspiration and of help in resisting useless fashions.

The Emergence Of Bacterial Genetics

Brock highlights and analyzes the experimental work that shaped and drove the field of bacterial genetics, focusing on the science rather than the personalities involved, illustrating his analysis with unpublished material and conversations with surviving investigators.