155 5.2 Bacterial conjugation Figure 5-4 Lederberg and Tatum’s demonstration of genetic recombination between bacterial cells. (a) The basic concept: two auxotrophic cultures (A 2 and B 2 ) are mixed, yielding prototrophic wild types (WT). (b) Cells of type A or type B cannot grow on an unsupplemented (minimal) medium (MM), because A and B each carry mutations that cause the inability to synthesize constituents needed for cell growth. When A and B are mixed for a few hours and then plated, however, a few colonies appear on the agar plate. These colonies derive from single cells in which an exchange of genetic material has occurred; they are therefore capable of synthesizing all the required constituents of metabolism. 5.2 Bacterial conjugation The earliest studies in bacterial genetics revealed the un-expected process of cell conjugation. Discovery of conjugation Do bacteria possess any processes similar to sexual reproduction and recombination? The question was answered by the elegantly simple experimental work of
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.