116 
It was pointed out by two groups of commentators that the Draft EIS 
did not discuss techniques for the isolation of large amounts of DNA 
sequences corresponding to genes by techniques other than recombinant 
DNA [20, 30]. While it is true, as pointed out by the commentators, 
that certain DNA sequences of sufficient purity have been isolated 
in useful amounts by classical biochemical techniques, the methods 
are relatively specific and yield only small amounts of the desired 
fragments, thus making demonstration of purity questionable in many 
instances. It is relevant to the consideration given to this comment 
that, with one exception --Dr. John Sedat's testimony in the transcript 
of a public hearing on recombinant DNA, February 9-10, 1976, at the 
NIH (l)--no other commentator on the Draft EIS, and no other partic- 
ipant in the 3-year discussion of recombinant DNA experiments, has 
seriously proposed that classical (non-recombinant) techniques could 
be usefully employed for the large-scale isolation of highly purified 
genes. 
The examples cited by these commentators [30 (2, 3)] refer to the 
isolation of DNA segments corresponding to the genes for mammalian 
globin (the protein portion of hemoglobin). The techniques are useful 
only when the messenger RNA for the particular gene itself can be 
isolated intact and in highly purified form in substantial quantities. 
Such procedures are applicable only to a small set of proteins made 
in highly specialized situations within organisms. Indeed, the DNA 
preparations described [30(2,3)] were specifically prepared for 
insertion into vectors, and subsequently host cells, by recombinant 
DNA procedures, in order to obtain useful quantities of the DNAs in 
question. Furthermore, these techniques, even ideally, are of limited 
value, since it is impossible to isolate by classical procedures those 
portions of the DNA contiguous to the gene which may play essential 
roles in gene expression and regulation. 
Insight into the relative advantages of classical and recombinant 
DNA techniques for the study of gene structure can be obtained by 
comparing the application of the two approaches to the study of histone 
genes. In this instance progress was again dependent on the ability 
to isolate relatively pure messenger RNA as well as on the special 
advantage obtained when the genes themselves occur many times in 
the DNA of the organism. While substantial information has been 
obtained by classical procedures (2, 3), isolation of the necessary DNA 
in sufficient quantity and purity was very difficult. These problems 
were effectively circumvented by recombinant DNA technology (4,5). 
The group utilizing the classical techniques (2) has recently stated that 
they are now isolating the histone genes by recombinant DNA method- 
ology (2). 
