| « Dolphin Punch! | Great White Shark Jam in Croatia? » |
Virgin Births Jump the Shark?
Behold. A child is born.
Nah, automictic parthenogenesis in Sharks is still pretty friggin cool. Automictic Parthenogenesis? What you talking about, Sharky?
Automictic Parthenogenesis is virgin birthing, asexual reproduction, baby! For a couple of years, this bizarre evolutionary behavior has been witnessed in Sharks in captivity. The latest credible example of the phenomena happened in May of 2007, when Tidbit, a female Blacktip shark, died after an accidental sedative overdose at the Virginia Aquarium & Marine Science Center. A necropsy of Tidbit showed that she had a nearly full term pup in her uterus. Since there were no male Blacktip Sharks living in Tidbit's enclosure, the only two possibilities were that she either mated with another species of Shark--which has never been scientifically recorded--or that she produced the embryo asexually. The results of DNA tests published on Friday in the Journal of Fish Biology, showed that Tidbit's pup only contained Tidbit's genes. Hooray for Automictic Parthenogenesis!
Scientists don't know whether Sharks exhibit this behavior only in captivity or if it happens in the wild as well. On the surface, this sounds like good news for declining Shark populations, as female Sharks, unable to find male mates could simply replicate their own DNA and keep the species going. NOT SO FAST! While asexual reproduction in Sharks is indeed an impressive evolutionary adaptation, it will not save Sharks from extinction. Aquarium Sharks that self-reproduce only produce a single pup at a time, while female Sharks often carry litters of a dozen or more pups when fertilized in the traditional method.
Also:
Absent the chromosomes present in the male sperm, the offspring of an asexual conception have reduced genetic diversity and, the scientists said, may be at a disadvantage for surviving in the wild. A pup, for instance, can be more susceptible to congenital disorders and diseases.
[source]
Reduced genetic diversity is bad. Have you ever been to Kansas? *shiver*
Uh, and just so that this post is not all about science, and making fun of Kansas and the Baby Jesus, here is a cool picture:
This one's for you, Tidbit.
![]()
--Sharky
technorati tags: sharks, Virginia, Christianity, Jesus, Science, Kansas, diversity, Blacktip Sharks, DNA, biology
