Life 2014, 4, 217-224; doi:10.3390/life4020217 OPEN ACCESS life ISSN 2075-1729 www.mdpi.com/journal/life Review Horizontal Gene Transfer among Bacteria and Its Role in Biological Evolution Werner Arber Biozentrum, University of Basel, Klingelbergstr. 50/70, CH-4056 Basel, Switzerland; E-Mail:
[email protected]; Tel: +41-61-267-2130; Fax: +41-61-267-2118 Received: 19 February 2014; in revised form: 22 April 2014 / Accepted: 23 April 2014 / Published: 16 May 2014 Abstract: This is a contribution to the history of scientific advance in the past 70 years concerning the identification of genetic information, its molecular structure, the identification of its functions and the molecular mechanisms of its evolution. Particular attention is thereby given to horizontal gene transfer among microorganisms, as well as to biosafety considerations with regard to beneficial applications of acquired scientific knowledge. Keywords: microbial genetics; gene vectors; recombinant DNA molecules; genetic variation; gene acquisition; evolution genes; natural selection; microbiome; gene domestication; laws of nature 1. Introduction The discovery of horizontal gene transfer is related to the introduction of experimental microbial genetics some 70 years ago. Soon thereafter, medical microbiology identified the raising problem of increasing antibiotic resistance of pathogenic bacteria. This medical problem stimulated research in bacterial genetics which revealed that horizontal gene transfer is involved in some of the genetic variations causing resistance to antibiotics. As a contribution to the history of scientific investigations, we trace here a sequence of steps of conceptual and experimental approaches to understand microbial evolution at the molecular level. This shall allow us to extrapolate to generally valid laws of nature guiding biological evolution by self-organization.