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Why look at G+C content?

Tue Mar 12 16:44:01 EST 1996

In article <Pine.SUN.3.91.960311121516.1660C-100000 at mcz>, dmw at MCZ.HARVARD.EDU
(Daniel Weinreich) says:
                                                            You apparently
>missed the point that in a SINGLE strand of DNA, the C-content is totally
>independent of the G-content.

        Sorry not true. Chargaff's rule applies to single-stranded DNA as
well as to double stranded DNA. For references see J. Mol. Evol. 41,573-581.
There is an abundant literature going back to Karkas in Chargaff's laboratory
in 1968.

                                ...but seeing as single stranded DNA does not
>undergo Watson-Crick base-pairing to itself, the G+C and A+T partition is
>arbitrary.  One might as well have chosen to report G+A content or G+T
>content, but there is less information in any one of these partitions
>than in the individual base frequencies themselves.

       Sorry, not true again. Single stranded DNA does undergo Watson-Crick
base pairing. For references see Mol. Biol. Evol. 12, 949-958;1157-1165.

                   Sincerely,  Don Forsdyke

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