Dragon foal: is this the birth of a new species? – mule’s foal
Sarah Boxer
DRAGON FOAL: IS THIS THE BIRTH OF A NEW SPECIES?
On March 4, 1981, in China’s Henan province,a mule mated with a jack donkey and gave birth to a foal. The newborn, dubbed Dragon Foal, was a chimera, with the tail and legs of a donkey, the shoulders and neck of a horse, and the head and ears of a mule. Other mules–the supposedly sterile progeny of mares and jack donkeys– have allegedly given birth, but this was the first scientifically documented case.
Four Chinese researchers, Rong Ruizhang,Cai Huidi, Yang Xiuqin, and Wei Jun, at the Institute of Genetics in Peking, analyzed the chromosomes of both the mother mule, who’s now dead, and the foal, who’s four years old and working as a cart horse. (The sire has been sold three times and is impossible to locate.) And the word, published in a recent issue of the Journal of the Royal Society of Medicine, is that the mother was indeed half horse and half donkey, and the foal is “some completely new kind of hybrid animal.’
Dragon Foal files in the face of geneticwisdom. The father predictably passed on a full set of donkey chromosomes to the foal. But the mother mule provided “a mixture of horse and donkey chromosomes,’ according to the researchers. This is strange indeed, because horse chromosomes and donkey chromosomes are generally presumed to be too different ever to join in a single fertile egg.
Before the chimera came along, geneticiststhought that there was but one way a mule crossed with a donkey could give birth to a viable foal: if the fertilized egg from the mule contained only horse chromosomes. Such a case was uncovered in the U.S. after the Chinese investigation began: a foal born to a mule had inherited only horse chromosomes from its mother and only donkey chromosomes from its father. In other words, the foal, christened Blue Moon (as in “once in a blue moon’), was nothing more than an ordinary mule.
But Dragon Foal broke the mold. “Thatsuch an odd combination of horse and donkey chromosomes could produce a viable offspring of sound constitution is remarkable,’ wrote the Chinese geneticists. Dragon Foal shows that horses and donkeys, despite their physical differences, are genetically very close.
“If you want to think of it as a new species,you can,’ says Rong, “because its chromosomes are different from those of any other animal. But at the moment I couldn’t say that it’s definitely a new species’–because it hasn’t successfully mated.
Some day, though, Dragon Foal, likeher mother, will be crossed (probably by artificial insemination) with a donkey or a horse. According to the geneticists, she has a much better chance than a mule of being fertile, since she’s a closer relative of the donkey. In the meantime, Rong hopes that the chimera’s celebrity will earn her an early retirement from her daily chores in the field.
Photo: Rong (capless, with Dragon Foal) saysthe new animal is part (from left) horse, mule, and donkey.
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