NEW DELHI // When Krishnan Shribiju, a government doctor, was posted to a hospital in rural Kerala 14 years ago, he began to hear and observe some curious things about the village of Kodinji.
In schools, teachers often got confused between students, routinely mistaking one for another. Clothing shops for children laid out attire only in matching sets of two.
When Dr Shribiju spotted a regular patient at a local government office and walked over to say hello, there was no response. “He said nothing. He was astonished,” he said. “I wondered why he wasn’t responding to me.
“That’s when I learned that he had a twin brother.”
Kodinji is a village of twins – a village where the rate of twin births far exceeds the norm.
Across the world, depending upon geography and ethnicity, the incidence of twin births per 1,000 live births ranges between 4 and 15. In Kodinji, a village of roughly 20,000 people, there are 36 sets of twins in every 1,000 births, according to Dr Shribiju. These include both identical twins – who develop from a single fertilised egg that splits into two – and fraternal twins – who develop from separate fertilised eggs but who can still look very alike.
However, there has been no genetic testing carried out to determine the percentage split between identical twins and fraternal twins in Kodinji.
Villages like Kodinji exist elsewhere in the world. Mohammadpur Umri, in the state of Uttar Pradesh, is one; there are others in Bosnia and Nigeria. Perhaps the most famous is Candido Godoi in Brazil, where, according to speculation, twin births rose soon after Josef Mengele, the Nazi doctor who experimented on twins in Auschwitz, arrived in the country. That theory has long been disproved, but scientists and doctors are still trying to determine why these pockets of twin births occur.
Twins run in the family, so if a person is part of a pair of twins, their descendants have a better chance of bearing twins as well. But Kodinji seemed to work differently, Dr Shribiju observed. “Even people who moved here from elsewhere, with no history of twins in their family, began to have twins.”
He found that Kodinji’s high rate of twin births was relatively recent – dating back three or four decades – and suspects an environmental factor, rather than genetics, is at work. However, he is still awaiting government clearance to begin the genetic studies he wishes to perform.
The main cause of twin births is women producing multiple eggs at once, said Giriraj Chandak, a geneticist at the Centre for Cellular and Molecular Biology in Hyderabad. This increases the chances of two eggs being fertilised at once – and therefore of fraternal twin births.
But what triggers this enhanced ovulation is difficult to say, Mr Chandak said.
In 2003, prompted by a slew of newspaper headlines about the twins of Mohammadpur Umri, Mr Chandak led a team of scientists there to conduct a brief study. At the time, he recalled, the village had 33 sets of twins in a population of roughly 1,500.
“There was only one deep well there, which had been around for a long time,” Mr Chandak said. “Everybody drew their drinking water from that well. The head of the village felt that the water had something in it.”
“In fact, to work out the environmental factors, we asked if there was a history of twinning in the domestic animals of the village also – the cows and goats and dogs,” he added. “Apparently there were 26 animals that had had twin births, and they all drank water from that particular well.”
But the theory went nowhere. “We looked for hormones and other agents in the water,” Mr Chandak said. “We didn’t find anything specific.”
Perhaps the closest scientists have come to circumstantial evidence for high twin birth rates is in Nigeria, in the town of Igbo Ora, which records a rate of 50 twins per 1,000 deliveries.
The town has a strong claim to being the twin capital of the world, Akeen Akinboro, a biologist at the Ladoke Akintola Institute of Technology in the town of Ogbomosho, told The National.
Mr Akinboro, who has been part of scientific teams studying Igbo Ora, said that a particular kind of yam eaten in the town and surrounding areas might be behind the prolific ovulation of women. “In the yam, there is a chemical that resembles the female hormone oestrogen,” he said. “This might be responsible for the multiple ovulation in the women who consume these yams.”
In Kodinji, home to so many twins that they have formed a Twins and Kin Association, life for its twins often involves stories of confusion that might be drawn straight out of a Shakespearean comedy.
P Saleena, who has an identical twin sister, was born in Kodinji and still lives there. “Even today, some of the older relatives in my family cannot tell the difference between us,” she told The National. “They recognise us by our husbands or by our children.”
A few years ago, when her sister got married, they decided to trick the groom, Ms Saleena said.
“In our community, there’s a tradition that after the wedding, the bride’s family goes to the house of the groom, but the bride stays behind at home,” she said. “My sister, however, called her new husband and told her she would be coming as well.”
In fact, Ms Saleena’s sister stayed home. “When the rest of our family went to his house, my brother-in-law saw me and got worried that she had actually broken tradition and come,” Ms Saleena said with a laugh.
“We had to convince him that it wasn’t her, it was me,” she said. “It was hilarious.”
ssubramanian@thenational.ae