I think it was a bad argument, perhaps due to weakness in Crick's knowledge of information science.
The argument goes like this;
Suppose you built a library of chemical reactions, to generate a DNA codon from
an amino acid, and did this for all of the different amino acids.
Since two different DNA sequences comple to the same protein, you could take sequence A, perform transcription and generate a protein P, and then construct a different DNA sequence B.
Thus we have "genetic information" extracted from a protein and stored in DNA, violating the Dogma... in an extremely cheesy way, since it's obviously the same "information" you had at the start, just encoded differently, and also it's not different in any meaningful sense from doing the same reverse engineering on non-logically-redundant DNA.
The argument goes like this;
Suppose you built a library of chemical reactions, to generate a DNA codon from an amino acid, and did this for all of the different amino acids. Since two different DNA sequences comple to the same protein, you could take sequence A, perform transcription and generate a protein P, and then construct a different DNA sequence B.
Thus we have "genetic information" extracted from a protein and stored in DNA, violating the Dogma... in an extremely cheesy way, since it's obviously the same "information" you had at the start, just encoded differently, and also it's not different in any meaningful sense from doing the same reverse engineering on non-logically-redundant DNA.