Mystery shark pregnancy, aquarium experts ponder

I paused for a bit wondering who'd want to hear another shark pregnancy story? But then I realized this one should go into what I fear may be a hard to fill category, so here it is:

Source: CNN article

...Asexual reproduction among sharks is more likely to happen in captivity, when there is no other option for reproduction, than in the wild, Hueter said.

Crossbreeding, on the other hand, is not known to happen at all among sharks, said Heather Thomas, aquarist at the John G. Shedd Aquarium in Chicago.

"It's not natural," Thomas said. "If you've got a shark that needs to swim to breathe and cross it with a shark that can lay on the bottom to breathe, what are you going to get? Are you going to get these weird mutations?"