Early last year a visiting Komodo dragon at the London Zoo laid a clutch of viable eggs that mystified zookeepers. The female dragon, Sungai, had been brought to England from Paris in hopes that she’d mate with one of the male Komodo dragons there. Unfortunately, she gave birth before she had a chance to meet her potential suitor.
Scientists clamored to explain the apparent immaculate conception. Sungai’s last known sexual encounter had been two years previous, but it was speculated that perhaps she was able to store the sperm for later use.
But now it turns out that it was indeed a virgin birth. Genetic tests done at the University of Liverpool shows that the DNA in all the offspring came from just the mother. The research appeared in the recent issue of the journal Nature
“I am delighted that the mysterious parentage of our Komodo dragon babies has been solved and that we have discovered something new to science at the same time,” said Richard Gibson, curator of herpetology at the Zoological Society of London.
“Knowing that the world’s largest lizard can reproduce like this suggests that many other reptiles may also do this more often than we thought and may lead to changes in the way we manage this and other species in breeding programs.”
Parthenogenesis has been known to take place in some reptiles but never the Komodo dragon species (Varanus komodoensis). The lizards can grow up to nine or ten feet in length, and are known to bite their prey with choppers full of lethal, bacteria-ridden saliva that slowly kills them
Sungai has since died, but another Komodo dragon, named Flora, at the Chester Zoo in England has laid eggs that are expected to hatch next month. And Flora has never met a male Komodo in her life. Tests done on three of her eggs that collapsed confirm the make-up of the DNA all derive from Flora.
Parthenogenesis is distinct from cloning. All of Flora’s offspring will be male because female Komodo dragons carry only dissimilar chromosomes (W and Z), so when one of their eggs divides it’s comprised only of similar chromosomes, either all W or all Z. (In humans it’s the male that carries the dissimilar chromosomes).
“This discovery has very important implications for understanding how reptiles are potentially able to colonize new areas. Theoretically, a female Komodo dragon in the wild could swim to a new island and then establish an entirely new population of dragons,” said Kevin Buley, curator of lower vertebrates and invertebrates at the Chester Zoo. “Essentially what we have here is an immaculate conception.”
Flora’s brood could hatch just in time for Christmas.