South African scientists report incredibly rare finding
South African researchers have reported what is believed be the world's first known pair of identical twin puppies.
Writing in the journal Reproduction in Domestic Animals scientists from the University of Pretoria describe how they were presented with the puppies after they were delivered at a local vet.
DNA profiling found that the puppies are monozygotic, or 'identical', twins - something that has been reported in the horse and pig, but is incredibly rare in other species apart from armadillos and humans.
"To the best of our knowledge, this is the first report of monozygotic twinning in the dog confirmed using DNA profiling," they write.
The pups were delivered by caesarian section at South Africa's Rant en Dal Animal Hospital. Their mother, a four-year-old multiparous Irish Wolfhound, had been in labour for two hours without success.
Veterinary surgeon Kurt De Cramer helped to deliver seven puppies but noticed there was a bulge in the uterus. Initially, he thought the bulge was another foetus. But, upon further investigation, he was shocked to find that it was two puppies sharing the same placenta.
"When I realised that the puppies were of the same gender and that they had very similar markings, I also immediately suspected that they might be identical twins having originated from the splitting of an embryo," Mr de Cramer told BBC News.
When the pups were six weeks old, Mr De Cramer handed the pups over to the University of Pretoria for DNA testing.
The researchers confirmed that the puppies were genetically identical and did not share similar genetics with any of the other puppies in the litter.
Image (C) Dr K De Cramer