In watching television journalism tackle large, difficult subjects, one often gets the sensation of a person trying to throw darts with his toes. One such agonizing performance airs tonight -- "The Gene Merchants" at 10 p.m. on Channel 7, an ABC News Closeup documentary.

The confusion is evident even in the news release for the show, which quotes Pamela Hill, executive producer of the ABC Closeup unit, as saying "this documentary is an in-depth examination of the genetic engineering revolution . . ." She follows this immediately with a list of a few of the many subjects that get a line or two in the show: "the rush to profits by corporations . . . the potential risks to society . . . we also examine the moral, ethical and religious questions . . ." All in depth, of course.

The modest executive producer does not mention the attempt in the same 50 minutes to explain -- in depth -- what genes are, how the intricate gene-splicing techniques work, the effect of competition in university research, something about test-tube babies, gene therapy and some of the possible benefits of gene splicing technology.

"The Gene Merchants" is divided into three parts, and the first, according to the ABC press release, "provides a comprehensive definition of genetic engineering, how it works, its benefits and its risks." The benefits take about two minutes and 50 seconds. The "comprehensive definition" and "how it works" comprise about three minutes in the show. Twenty-three sentences, by my count.

Oddly, even though the ABC team chose to drive past a long list of subjects like signposts glimpsed from a speeding car, the show still seems empty and even repetitious.

Other oddities compound the felony. A number of ghostly voices are heard throughout the show. No faces are shown, and no names are run on the screen to identify the speaker. Is this the new TV version of the unattributed quote that newspaper reporters are so fond of? Unnamed voices said today . . .

In a whining segment on the new genetic-engineering businesses, the show repeats for the thousandth time that the companies have few products and are being supported on hope and speculation by scientists, businessmen with cash, and stockholders. ABC reporter William Sherman then points out that the companies hold press conferences and announce their achievements. This, he says, "is not in keeping with the exacting tradition of science . . . breakthroughs are usually published in professional journals . . . only after extensive review by other scientists to insure the findings are authentic and not self-serving." Apparently in mid-thought, Sherman forgot he was talking about business, not science.

At another point in the show, an unidentified ABC reporter is shown questioning the former director of the National Institutes of Health, Donald Frederickson. The reporter, sounding as if he has discovered something, asks if just anyone could start splicing genes in his backyard shed. Yes, Frederickson says. "Who's keeping an eye on that?" the reporter asks meaningfully.

Is it possible for just anyone to do journalism in his backyard shed? Yes, and this documentary is a good example of what might result.

For all the talk throughout the piece of the momentous nature of the new work in biology, and our new depth of understanding of the mechanisms of life, it is clear that ABC was not listening to its own voices. The Closeup series has done some good work in the past, and it is surprising that for this hour the team utterly failed to take a good subject seriously.