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Paradigms

Darwin versus Adam

Advance of creationism mobilizes a scientist in defense of the Theory of Evolution

The debate between the fundamentalist ideas about creation and the Theory of Evolution, unquestionably deflagrated in 1859 with the publication of The Origin of Species by Charles Darwin, is about to celebrate 150 years without losing its wind or passion. The creationists, who never accepted the theory of natural selection, nor consider the scientific evidence accumulated throughout these almost one hundred and fifty years, recently returned to the charge with a more subtle argument, that of design intelligence: the complexity of man and his perfection are the results – and the concrete proof – of a divine project. This vision has been gaining followers throughout the world, notably in the United States, where it has even reached the status of a discipline in public schools.

The intensification of neo-creationism – which is no more than creationism in a “cheap tuxedo” in the vision of the biologist Leonard Krishtalka, the director of the Natural History Museum of the University of Kansas – is mobilizing researchers in defense of science, of evolutionism and of Darwin himself, including in Brazil. So much so that it was the theme of the 5th São Paulo Research Conference, sponsored by the Pro-Rectory of Research of the University of Sao Paulo (USP), held between the 18th and 20th of May. “All living beings descent from a single ancestor or from a very small number of primitive forms. We’re the same by chance, and not because of an intelligence project”, says José Mariano Amabis, from the Genetics and Evolution Biology Department of USP’s Biosciences Institute, giving a start to the marathon of conferences that maintained captive, by inebriation, an audience of more than 350 young biologists, philosophers, geneticists and anthropologists, among others.

The fundamentalist’s anger is understandable, after all Darwin decreed the “death of Adam”, says Aldo Mellender de Araújo, from the Biosciences Institute of the University of Rio Grande do Sul (UFRGS), referring to the sentence pronounced by the Englishman John C. Greene. “It’s like confessing to a crime”, to have recognized Darwin himself, according to his biographers Adrian Desmond and James Moore. It was not by chance that he – who at one time had considered his father’s suggestion of becoming a clergyman when his lack of aptitude for medicine became clear – waited 20 years before publishing The Origin of Species. He only did this when another naturalist, Alfred Wallace, was close to publishing the results of his research. Both of their work was presented to the Linnean Society, in an article signed by the two authors in 1858.

The reaction against natural selection ignited Europe, so much so that in the five subsequent editions of his most famous work Darwin saw himself obliged to debate with his critics, revising and modifying the text. The advance of biology, of genetics and of molecular biology during the 20th century, nevertheless, conferred upon it a status similar to that of Copernicus in the pantheon of science, in the evaluation of the anthropologist Eunice Ribeiro Durham, from USP’s Research Center of Tertiary Education. “Darwin altered the position of man in relation to the Universe.”

Darwinism consolidated itself during the 20th century, between 1930 and 1950, when various authors “made the synthesis theory of evolution, marrying genetics with the selection of species, thus creating new paradigms for science”, observes Francisco Salzano, from the Biosciences Institute of UFRGS, a pioneer in the study of genetics of indigenous populations. “Afterwards the discovery by Watson and Crick, about the structure and function of DNA, opened up the prospect for the development of techniques that would push forward the research of fantastic forms”, he underlines. He himself investigated, some 50 years ago, the origin of the indigenous peoples of the Americas by using two uniparental markers “mitochondrial DNA and the Y chromosome  – that suggested that man may have arrived on the continent some 40,000 years ago, and not 20,000 years as had been supposed by the then theories. Salzano is now beginning to analyze the genetic origin of some illnesses.

Molecular biology offers relatively safe clues to the origin of modern man: “It was in Africa about more or less 165,000 years ago”, says the geneticist Sérgio Danilo Pena, from the Biomedical Department of the Federal University of Minas Gerais (UFMG), referring to Homo sapiens idaltu, considered, up until now the oldest fossil of Homo sapiens. “Genomic diversity reflects this evolution”, he says. The problem he underlines, is that a good scientific experiment must be repeated various times and this has to be done once only. “We know the initial state and we will never know if the result is correct”, he ponders.

Throughout the world researchers are attempting to reconstruct the origin of humanity using the technique of cellular markers, taking as a reference a data bank with 1,064 DNA samples of people from 52 populations from all of the continents. Geneticist Pena’s team is using a data bank and 40 markers called indels – an acronym that brings together two words: insertions (gains) and deletions (loses) – of adenine, guanine, cytosine and thymine. For example, it has already been verified that 85.62% of genetic variations can be found on the same continent “We’re equally unequal”, he says.

There is only one consensus of opinion about the origin of modern man, from the point of view of molecular biology, as yet there are divergences as to the model of occupation of the Americas when one takes into consideration the morphology of our ancestors. There are at least two models of analysis available: that in which the continent was peopled by three waves of migration of Asiatic origin, with oriental traits (Mongoloids); and that of a single migration. Professor Walter Neves, from the Human Evolution Studies Laboratory, of USP’s Biosciences Institute, considers a third hypothesis: that in which America was occupied by two migratory waves coming from Asia. The first – whose craniums are found at Lagoa Santa – appear to have become extinct, whilst the second gave descendants to all of the indigenous tribes of the Americas.

Molecular biology, the light shining on the evolution paradigm, is revealing. For example, it permits Bianca Zingales, from USP’s Chemistry Institute, to have identified two species of Trypanosoma cruzi, the agent that causes Chagas’ disease. “We concluded that there’s a dimorphism of the gene”, she says. The theories of evolution also provide news about the main enemies of man: infectious agents. “HIV is virulent because the virus because the virus has still not completely evolved. The ebola virus as well. When killed off rapidly, it doesn’t have time for transmission”, explains Jorge Kalil, from USP’s Medical School. In the fight between man and the infectious agent an evolutionary barrier exists, he says, during a stimulating conference about innate and acquired immunities. For Henrique Krieger, from USP’s Biosciences Institute, evolutionism was the impulsive thrust for modern biology. “Without this, the studies would be extremely boring.”
For next year new debates are already programmed concerning the origin of life; the brain and thought as well as drugs and dependency.

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