Biologist and paleontologists are all familiar with the name of Lynn Margulis. Now 73, she made her reputation in the 1960s for her “endosymbiosis” hypothesis: the idea that complex eukaryotic cells with all their organelles were assembled from prokaryotes which came to live symbiotically within the walls of other prokaryotic cells. Her hypothesis was first proposed by Merezhovsky in 1905 and Wallin in 1920, but Margulis used the great advances in microscopy and microbiology in the 1960s to show that the idea was highly plausible. At first, her papers were rejected by at least 15 journals before they were finally published. But as time passed, the evidence for much of her “outrageous idea” continued to accumulate. It does indeed appear that the chloroplasts of the eukaryotic cell are derived from symbiotic cyanobacteria (as it is common that many animals, from large benthic foraminifera to hermatypic corals to giant clams, use algae in their own tissues symbiotically), and that mitochondria were once purple non-sulfur bacteria. The best evidence comes from the fact that organelles have their own DNA independent of the cell’s nuclear DNA (we hear about research on mitochondrial DNA all the time); that organelles can divide independently of their host cell and have their own ribosomes; that organelles can be killed by antibiotics, just like their prokaryote ancestors, while the host cell is not killed. In addition, there are now numerous examples of eukaryotes which still use endosymbiotic prokaryotes to perform various functions, and have not completely absorbed and transformed them into organelles of the host cell. Over the years, Margulis has promoted additional ideas about the importance of symbiosis in biology, and has become a major advocate of the “Gaia” hypothesis and how all of life is dependent on the rest of life in an intricate, delicate web.

Margulis’ sheer determination in getting her ideas heard, and finding scientific evidence to support them, was remarkable, especially in a age where the idea was highly unorthodox. But she was never an orthodox scientist to begin with. Admitted to the University of Chicago when she was 14, she married Carl Sagan when she was 19, and her son Dorion Sagan is a frequent coauthor with her on her books. Her other child with the great astronomer, Jeremy Sagan, is a software developer and the founder of Sagan Technology. As the years go by and more and more people recognize her pioneering work, she has received all sorts of honors: membership of the National Academy of Sciences in 1983, the 1999 National Medal of Science, the 2008 Darwin-Wallace Medal, the William Procter Prize for Scientific Achievement, and her papers are archived at the Library of Congress.

Thus, it is with shock and sadness that I read her recent interview in Discover magazine (April 2011, pp. 66-71). It’s one thing to read about her argument for “symbiogenesis” as more important to evolution than natural selection. That’s yet another controversial idea she has long pushed, and it’s plausible that evolution works faster with the insertion of gene sequences, especially from parasites and viruses. Indeed, the discovery of ERVs (endogenous retroviruses, fragments of DNA that once infected the genome and are now passively copied in each generation as a silent selectively-neutral fossils of past events) tends to support this idea a bit. But the the interview gets stranger and stranger, such as when she criticizes all of population genetics as “numerology”, or this weird exchange:

Interviewer: Some of your criticisms of natural selection sound a lot like Michael Behe, one of the most famous proponents of “intelligent design,” and yet you have debated Behe. What is the difference between your views? Margulis: The critics, including the creationist critics, are right about their criticism. It’s just that they’ve got nothing to offer but intelligent design or “God did it.” They have no alternatives that are scientific.

Thanks, Lynn. You can bet that parts of that quote will show up on the Discovery Institute site, and in a lot of future creationist books and blogs and debates. Our job clarifying the public myths of evolution is hard enough without someone as famous and honored as Margulis spouting misconceptions and outright mistakes that just beg for creationists to quote-mine them.

But the final straw is when she slips outside the realm of science entirely, and becomes a full-fledged AIDS denier. My jaw just dropped when I read the following:

There is a vast body of literature on syphilis spanning from the 1500s until after World War II, when the disease was supposedly cured by penicillin. It’s in our paper “Resurgence of the Great Imitator.” Our claim is that there’s no evidence that HIV is an infectious virus, or even an entity at all. There’s no scientific paper that proves that the HIV virus causes AIDS. Kary Mullis said in an interview that he went looking for a reference substantiating that HIV causes AIDS and discovered, “There is no such document.”

How can she call herself a serious biologist and say something like this? Has she never actually LOOKED at the hundreds of peer-reviewed scientific papers documenting the structure of the HIV virus, and the clear documentation of that virus in patients that suffer and die from AIDS? Or the fact that patients treated with anti-retrovirals manage to suppress their AIDS symptoms? Or the disaster in South Africa, when the government became active AIDS deniers, spread misinformation and myths about AIDS, and the infection rate shot up? Not even the hard-core AIDS deniers like Peter Duesberg deny that the HIV virus exists! And citing notorious “bad boy” Kary Mullis (famous for all sorts of odd ideas–see below) is not the best way to encourage people to accept her hypothesis.

So if syphilis causes AIDS, and not HIV, where is the evidence? As microbiologist and epidemiolist Tara Smith points out in her excellent blog, Margulis offers none. Instead, she says to the credulous and uncritical interviewer:

The idea that penicillin kills the cause of the disease is nuts. If you treat the painless chancre in the first few days of infection, you may stop the bacterium before the symbiosis develops, but if you really get syphilis, all you can do is live with the spirochete. The spirochete lives permanently as a symbiont in the patient. The infection cannot be killed because it becomes part of the patient’s genome and protein synthesis biochemistry. After syphilis establishes this symbiotic relationship with a person, it becomes dependent on human cells and is undetectable by any testing.

Great. Just what we need: an untestable hypothesis promoted by assertion and reputation, not something concrete that scientists could test (although most specialists in microbiology would say the evidence is clear that the HIV retrovirus, and not the spirochaete bacterium Treponema pallidum, is the true cause of AIDS).

The phenomenon is a familiar one: let’s call it “the Linus Pauling effect.” A highly respected and honored senior scientist, largely out of the mainstream and not up to date with the recent developments (and perhaps a bit senile), makes weird pronouncements about their pet ideas–and the press, so used to giving celebrities free air time for any junk they wish to say, prints and publishes it all as if it is the final truth. The great Linus Pauling may have won two Nobel Prizes, but his crazy idea that megadoses of Vitamin C would cure nearly everything seems to have died with him. William Shockley may have won a Nobel for his work on transistors, but his racist ideas about genetics (a field in which he had no expertise) should never been taken seriously. Kary Mullis may have deserved his Nobel Prize for developing the polymerase chain reaction, but that gives him no qualifications to speak with authority on his unscientific ideas about AIDS denial and global warming and astrology (he hits the trifecta for pseudoscientific woo).

And now we have Margulis muddying the waters for all of us, and the press publishes her ideas with no challenges or discussion. Tara Smith says it best:

I get that Margulis feels she got the short end of the stick from the scientific establishment. I get that she sees herself as a maverick, a radical, a perpetual outsider. I also get that she has an ego the size of Texas. The last question she’s asked in the interview is “Do you ever get tired of being called controversial?” Her response: “I don’t consider my ideas controversial. I consider them right.” While confidence is certainly an important trait in a scientist, so is the ability to twist your ideas around, look for the holes, test them, revise them, lather rinse repeat. You can’t let your ego blind you to the fact that, hey, *you might be wrong.* Margulis not only refuses to consider this, she admits that she has “no interest in the diseases” she’s discussing, even while she claims to know more about their causes than the scientists who have spent decades studying them. In a lot of ways, this makes Margulis worse than the creationists she dismisses.

Any other readers out there have another famous example of a respected and lauded senior scientist who makes the news talking about subjects that are entirely outside his or her expertise? Feel free to nominate your candidates for the “Linus Pauling Award.”