The astonishing story of genetic research on humans, which took 10 years to uncover, is likely to shake the world of anthropology to its core, according to Professor Terry Turner of Cornell University, who has read the proofs.

"In its scale, ramifications, and sheer criminality and corruption it is unparalleled in the history of anthropology," Prof Turner says in a warning letter to Louise Lamphere, the president of the American Anthropology Association (AAA).

The book accuses James Neel, the geneticist who headed a long-term project to study the Yanomami people of Venezuela in the mid-60s, of using a virulent measles vaccine to spark off an epidemic which killed hundreds and probably thousands.

Once the epidemic was under way, according to the book, the research team "refused to provide any medical assistance to the sick and dying Yanomami, on explicit order from Neel. He insisted to his colleagues that they were only there to observe and record the epidemic, and that they must stick strictly to their roles as scientists, not provide medical help".

The book, Darkness in El Dorado by the investigative journalist Patrick Tierney, is due to be published on October 1. Prof Turner, whose letter was co-signed by fellow anthropologist Leslie Sponsel of the University of Hawaii, was trying to warn the AAA of the impending scandal so the profession could defend itself.

Although Neel died last February, many of his associates, some of them authors of classic anthropology texts, are still alive.

The accusations will be the main focus of the AAA's AGM in November, when the surviving scientists have been invited to defend their work. None have commented publicly, but they are asking colleagues to come to their defence.

One of the most controversial aspects of the research which allegedly culminated in the epidemic is that it was funded by the US atomic energy commission, which was anxious to discover what might happen to communities when large numbers were wiped out by nuclear war.

While there is no "smoking gun" in the form of texts or recorded speeches by Neel explaining his conduct, Prof Turner believes the only explanation is that he was trying to test controversial eugenic theories like the Nazi scientist Josef Mengele.

He quotes another anthropologist who read the manuscript as saying: "Mr. Tierney's analysis is a case study of the dangers in science of the uncontrolled ego, of lack of respect for life, and of greed and self-indulgence. It is a further extraordinary revelation of malicious and perverted work conducted under the aegis of the atomic energy commission."

Prof Turner says Neel and his group used a virulent vaccine called Edmonson B on the Yanomani, which was known to produce symptoms virtually indistinguishable from cases of measles.

"Medical experts, when informed that Neel and his group used the vaccine in question on the Yanomami, typically refuse to believe it at first, then say that it is incredible that they could have done it, and are at a loss to explain why they would have chosen such an inappropriate and dangerous vaccine," he writes.

"There is no record that Neel sought any medical advice before applying the vaccine. He never informed the appropriate organs of the Venezuelan government that his group was planning to carry out a vaccination campaign, as he was legally required to do.

Fatalities

"Neither he nor any other member of the expedition has ever explained why that vaccine was used, despite the evidence that it actually caused or, at a minimum, greatly exacerbated the fatal epidemic."

Prof Turner says that Neel held the view that "natural" human society, as seen before the advent of large-scale agriculture, consists of small, genetically isolated groups in which dominant genes - specifically a gene he believed existed for "leadership" or "innate ability" - have a selective advantage.

In such an environment, male carriers of this gene would gain access to a disproportionate number of females, reproducing their genes more frequently than less "innately able" males. The result would supposedly be a continual upgrading of the human genetic stock.

He says Neel believed that in modern societies "superior leadership genes would be swamped by mass genetic mediocrity".

"The political implication of this fascistic eugenics is clearly that society should be reorganised into small breeding isolates in which genetically superior males could emerge into dominance, eliminating or subordinating the male losers in the competition for leadership and women, and amassing harems of brood females." Prof Turner adds.

In the memo he says: "One of Tierney's more startling revelations is that the whole Yanomami project was an outgrowth and continuation of the atomic energy commission's secret programme of experiments on human subjects.

"Neel, the originator of the project, was part of the medical and genetic research team attached to the atomic energy commission since the days of the Manhattan Project."

James Neel was well-known for his research into the effects of radiation on human subjects and personally headed the team that investigated the effects of the Hiroshima and Nagasaki bombs on survivors and their children.

According to Prof Turner, the same group also secretly carried out experiments on human subjects in the US. These included injecting people with radioactive plutonium without their knowledge or permission.

Nightmarish

"This nightmarish story - a real anthropological heart of darkness beyond the imagining of even a Joseph Conrad (though not, perhaps, a Josef Mengele) - will be seen (rightly in our view) by the public, as well as most anthropologists, as putting the whole discipline on trial," he says.

"This book should... cause the field to understand how the corrupt and depraved protagonists could have spread their poison for so long while they were accorded great respect throughout the western world... This should never be allowed to happen again."

Yesterday Professor Turner told the Guardian it was unfortunate that the confidential memo had been leaked, but it had accomplished its original purpose in getting a full response from the AAA.

A public forum would be held at its AGM in November to discuss the book its revelations and courses of action.

In a statement yesterday the association said "The AAA is extremely concerned about these allegations. If proven true they would constitute a serious violation of Yanomami human rights and our code of ethics. Until there is a full and impartial review and discussion of the issues raised in the book, it would be unfair to express a judgment about the specific allegations against individuals that are contained in it.