111. BACTERIOPHAGE DNA AXD BACTERIAL DXA 



129 



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Fig. 6. A comparison of the band forms of T2 and T4 whole molecules with 

 that of formaldehyde-reacted polynucleotide chains derived from them. The Gaus- 

 sian bands produced by native and denatured whole DNA molecules are shown on 

 the same graph by plotting the log of the band height vs the band width. The 

 whole duplex molecules fall on the steepest curve, while the polynucleotide chains 

 fall on a curve which has a twofold lower slope; a fact which indicates that their 

 relative molecular weight is lower by a factor of 2. (From Berns and Thomas, 1961.) 



