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A 1963 radioautograph of an E. coli chromosome

radioautograph of an intact E. coli chromosome

From Small Things Considered:

We continue our series of images that have made a difference in microbiology. This one, published by John Cairns in 1963 has earned a most deserved place in textbooks and re­views. It shows a radioautograph of an intact E. coli chromosome in the act of repli­cat­ing. From this image, Cairns concluded that the E. coli chromosome is: i) a single piece of double stranded DNA, 700−900 μm long, and ii) circular.

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