THE NEW SCIENCE of gene-splicing, known also as recombinant DNA, passed historic landmarks on two very different fronts this week. On the same day that this year's Nobel Prize in chemistry was awarded to three scientists who pioneered the basic research, on Wall Street the first public offering of shares in a genetic engineering firm touched off one of the hottest days of buying on record. The coincidence of the two events is an accurate reflection of the explosive speed with which these discoveries have made the leap from the laboratory into the realm of commercial application.

The Nobel Prize was shared by two Americans -- Paul Berg of Stanford University and Walter Gilbert of Harvard -- and a Briton, Frederick Sanger. With this award, Dr. Sanger became only the fourth person in history to win two Nobel Prizes, preceded by physicists Marie Curie and John Bardeen and chemist Linus Pauling.

Drs. Sanger's and Gilbert's awards were for the discovery of methods of reading the information contained in the DNA molecule. DNA is the chemical name for the genetic substance. It is made up of very long sequences of four subunits: an individual gene may be composed of 1,000 or more. The four subunits are the equivalent of a four-letter alphabet that is read only in words of three letters. This key to the genetic code and the chemical meaning of each of its 64 words was discovered some years ago. What was not known before Drs. Sanger's and Gilbert's work was how chemically to determine the sequence of subunits found in any particular gene. Their methods allow scientists to determine the sequence of any desired gene, and therefore they also make possible the artificial synthesis of genes once the sequence is known.

This ability to decipher the gene's information is one key feature of the recent revolution in biochemistry. The other is the ability to manipulate genes -- in particular the ability to separate a single gene from the thousands in a cell and transfer it to bacteria that will reproduce it in great quantity, enough for detailed study and eventually for commercial application. Dr. Berg was the individual who led the field in this area, the man who is often called the "father" of recombinant DNA.

Though his Nobel citation does not mention it, Dr. Berg also deserves recognition for the exemplary handling of his discovery. Recognizing the great power of these new techniques -- for good and possibly ill -- he resisted the temptation to race ahead with his work, and was one of the first to call for the establishment of guidelines for such experiments and for a moratorium on all such work until suitable rules could be drafted.

So far, thanks in large part to the caution and sense of public responsibility exercised by Dr. Berg and others, the era of recombinant DNA and of biotechnology has had a safe beginning. Though Wall Street's enthusiasm is probably excessive -- yesterday's stock offering of a company that has lost $1 million in its four years of existence started at $35 a share and closed at $80 -- it also promises to open up a time of excitement and productivity for both science and industry.