In Brazil, a rogue gene and a boom in twins

SANTIAGO, Chile - For years, so many twins have been born in the small southern Brazilian town of Candido Godoi 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 here.

But a group of scientists now says a series of DNA tests conducted on about 30 families found that a specific gene in the population of Candido Godoi appears more frequently in mothers of twins than in those without. The phenomenon is compounded by a high level of inbreeding among the population of mostly 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," said Ursula Matte, a geneticist in Porto Alegre, Brazil.