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Videos
The DNA Story - 1973
 James Watson
Author: James Watson
Length: 1:38
 Watch using MPG Size: 10.0MB
Transcript:
Watson: Astbury had the idea that a DNA molecule was a long linear molecule - where the bases stacked on top of each other
like piles of pennies. The other thing we used was what Maurice Wilkins told us from the dimensions of the crystalline form,
there was clearly more than one chain in a nucleic acid molecule. It was difficult to decide exactly how many because you
had to measure the density accurately, and that wasn't that simple, but he thought there was between two and three. My recollection
is that their preference was for three. The other thing that we thought about was that since it crystallizes, it must be very
regular. But it was sort of our tenet that the sequence of bases along this molecule were going to be irregular, and we thought
they were going to be irregular because we thought that's what would convey the genetic information. People now think that
was a great idea, but there was no other idea you could have. It was as simple minded as it could be - if nucleic acids conveyed
information, it was with the sequence of the four bases. Now, if they crystallize, well the bases being irregular, we thought,
four different types, four different shapes. That meant that the regular pattern must come from the sugar-phosphate backbone.
We thought that if there were several chains, and if they pack together regularly to form crystal, then the sugar phosphate
would have to be in the center of the molecule.
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