Remember Flora? The Komodo dragon? I blogged about her here and here. She produced offspring using parthenogenesis while in captivity last year. Well, there was a news story earlier this week about a bonnethead shark in in the Henry Doorly Zoo in Nebraska giving birth to a pup. (Interestingly, zoo-keepers and news reporters seemed uninterested in giving our subject shark a name, as happened for the reptile.)
It was a puzzle for a while as to how she did it (as I learned in a BBC article):
At the time, some theorised that a male tiger shark kept at the zoo could have been the father – but the institution’s three bonnethead females had none of the bite marks that are usually inflicted on their gender during shark sex.
Some even suggested that one of the females could have had sex in the wild and stored the sperm in her body – but the three-year period in captivity made this explanation highly unlikely.
But eventually DNA tests resolved the issue:
The new tests on the dead pup’s tissues now show the newborn’s DNA only matched up with one of the females – and there was none of any male origin.
The article (read it for more information, including the discussion of how this might be useful in conservation efforts – but with caution about loss of genetic diversity) ends with a nice graphic illustrating the difference between parthenogenesis and the more common form of vertebrate reproduction:
-cvj
