Hanna Retallack and the DeRisi Lab were recently profiled in a National Geographic story about the microbial pathogen that's been killing sharks and rays in the San Francisco Bay since early this year. Collaborating with California Fish and Wildlife pathologist Mark Okihiro, who sent vials of cerebrospinal fluid to the DeRisi lab for analysis, Hanna was able to help identify what might be causing these deaths.
From the article:
Retallack took Okihiro’s leopard shark samples and used a technique called next-generation sequencing to look at all the DNA and RNA in the fluid, to see where it had come from. While 99 percent of the genetic material present was “shark,” she was able to extract and analyze the other one percent. Among the leftovers one sequence of RNA stood out.
Retallack noted the sequence, compared it against all known sequences in a database at the National Center for Biotechnology Information, and found a match: a well-known fish-killing parasite called Miamiensis avidus.
“I’m very confident that in these animals there’s Miamiensis avidus,” Retallack said. “We have a very good species-level identification at the molecular level. The RNA we see in there is quite specific to this species.”