Richard Lenski

Richard E. Lenski ( born August 13, 1956) is an American evolutionary biologist.

Life

Richard E. Lenski is the son of sociologist Gerhard Lenski.

Training

Lenski earned his diploma in 1976 (Bachelor of Science) at Oberlin College and received his doctorate in 1982 at the University of North Carolina. Since 1985, he was first an assistant professor from 1988 to 1991 and associate professor at the University of California, Irvine. Since 1991 he has been Distinguished Professor Hannah at Michigan State University.

He is a member of the American Academy of Microbiology (AAM ) of the American Society for Microbiology (ASM ) and the American Academy of Arts and Sciences. In 1996 he received a MacArthur Fellowship and was elected to the National Academy of Sciences, 2006. He was co-editor of Theoretical Population Biology (1990-1992), evolution (1990-1996), Microbial Ecology (1991-1999), Molecular Ecology (1994 ), The American Naturalist (1996-1998 ) and member of several committees: National Research Council Commission on Life Sciences (1990-1996), National Research Council Board on Biology (1991-1993), National Science Foundation population Biology Review Panel (1995), Society for the Study of Evolution ( 1997).

Research area

In addition to his work with digital organisms Avida Lenski has been known by a long-term experiment on the evolution of Escherichia coli, which began on 15 February 1988. He regularly publishes on its website information on the course of the experiment.

E. coli long-term experiment

The E. coli long-term experiment to document how natural selection (English survival of the fittest, dt the survival of the best adapted organism), the paradigm of the theory of evolution by Charles Darwin, in the laboratory is understandable and observable.

The model organism is Escherichia coli. This intestinal bacteria use glucose as a natural food source; with citrate as a carbon source can not grow the wild type E. coli. Lenski sets since 1988, E. coli without drastic external influences - such as hard radiation or mutagenic chemicals - a growth medium that contains a minimum supply of glucose, but an oversupply of non- metabolizable food source citrate.

All steps are carried out according to standard protocols. In the first step - starting from a single prokaryotic E. coli cell that divided several times - Lenski chose twelve daughter cells, which served as a starter for each of the twelve experiments that are pursued in parallel since 1988:

  • Every day, the E. coli cultures are shared and provided with fresh medium ( " propagated ").
  • Every 75 days ( approximately 500 generations), samples are taken of the E. coli population and frozen for documentation.
  • In these populations, the growth rate is estimated (relative to the origin of the population). Should not change E. coli, the growth rate should not change. If, however, the growth rate increases, then E. coli by random mutation (s) would have adjusted to the new food source.

In June 2008, published Lenski and co-workers that had developed after 31,500 generations in one of the twelve parallel experiments an E. coli population that is able to use citrate as a carbon source. The genetic mutations that have led to this completely new ability of E. coli are present in the new E. coli strain, and its - examines precursor generations - over the last 20 years frozen.

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