SANTIAGO, Chile — For years, so many twins have been born in the small southern Brazilian town of Cândido Godói that residents wonder whether something mysterious lurks in the water, or even if Josef Mengele, the Nazi physician known as the Angel of Death, conducted experiments on the women there.
But a group of scientists now says it can rule out such long-rumored possibilities. Ursula Matte, a geneticist in Porto Alegre, Brazil, said a series of DNA tests conducted on about 30 families since 2009 found that a specific gene in the population of Cândido Godói appears more frequently in mothers of twins than in those without. The phenomenon is compounded by a high level of inbreeding among the population, which is composed almost entirely of German-speaking immigrants, she said.
“We analyzed six genes and found one gene that confirms, in this population, a predisposition to the birth of twins,” Dr. Matte said.
She was the first scientist to document, in a study published in the 1990s, that the rate of twin births in the town was unusually high. It was especially high in São Pedro, a village of about 350 residents that is part of Cândido Godói. Dr. Matte found that from 1990 to 1994, 10 percent of the births in São Pedro were twins, compared with less than 1 percent for Brazil as a whole.
The high concentration of twins has stirred outlandish theories. Residents say Mengele moved around southern Brazil in the 1960s, posing as a veterinarian, at about the time the twin births were thought to have really taken off. An Argentine journalist suggested in a 2008 book that Mengele conducted experiments on women in Cândido Godói that resulted in a baby boom of twins, many of whom have blond hair and light-colored eyes.
Mengele, who died in Brazil in 1979, was notorious for his often-deadly experiments on twins at Auschwitz, ostensibly in an effort to produce a master Aryan race for Hitler.
But the study led by Dr. Matte analyzed 6,615 baptism certificates dating back 80 years in the predominantly Roman Catholic town and found that the twins phenomenon existed in the 1930s, “long before Mengele’s period,” she said.
“In the initial stages of our research we immediately disproved any involvement with Mengele,” Dr. Matte said.
Her team of 20 researchers also analyzed the town’s water supply — residents believe a mysterious mineral may be responsible for the high rate of twin births — and uncovered no abnormalities.
While studying the baptism certificates, the scientists confirmed that the highest concentration of twins has been in São Pedro, with 33 pairs out of 436 births from 1959 to 2008, all living in a one-and-a-half-square-mile area.
In São Pedro, they concluded their research by analyzing last names and conducting genetic tests on women. “With a small population of about 80 families, it was a challenge to find women that did not have twins within a first-degree relation,” Dr. Matte said.
The scientists believe that a small number of immigrant families living in São Pedro may have brought the variant gene to the region. “This does not mean that it is a universal gene,” Dr. Matte said. “If I take twins from New Zealand and test them, it will probably generate a different result.”
Dr. Matte has yet to publish the results of her findings but was set to present them in Cândido Godói on Friday.
“The entire city supports this study, and they have great hopes of finding out why they have so many twins, and to better understand what is behind their story,” said Daniela Junzvier, the culture coordinator at the mayor’s office.
