PSU Magazine Summer 1989

Dolphins and DNA D elective work has come a long way since Sherlock Holmes. Now, instead of looking at a dusted fingerprint through a magnifying glass, a detective is more likely to look at living tissue through a microscope. And that in– cludes the most telling fingerprints of all: DNA , the living code that provides the most detailed portrait known to science. PSU biologist Debbie Duffield is a kind of detective, using DNA to keep track of how marine mammals interact, migrate, live and die in an increasingly threatened environment. It is through this kind of footwork that she and other scien– tists can assess the health - or lack of it - of an animal population and do a better job of judging what steps are necessary to protect them . Duffield has been involved in marine mammal rescue in the Pacific Northwest for quite some time as regional coor– dinator of the Marine Mammal Stranding What if a major oil spill occurred off the Florida coast? Would the dolphins be wiped out forever. .. ? Network. When a seal , whale or some other marine mammal is found alive on a beach, the group works to help the animal. If it is dead , they will investigate the cause. Unnatural demise among marine mam– mals in this region come under a number of common causes. Many sea lions are shot by fishermen trying to protect their catch. Whales occasionally collide with ships. She hasn't seen much in the way of pollution effects on Northwest mammals, but the possibility always exists, and is something she keeps in mind as part of her biggest research project: the study of bottlenose dolphins in Florida. What if a major oil spill occurred off the Florida coast? Would the dolphins be wiped out forever, or could they somehow recover? Duffield's work with DNA , with the help of her colleague, Dr. Randall Wells in Sarasota, is finding possible answers. Wells temporarily captures dolphins from varying populations, takes blood samples and ships them to Duffield, where she uncovers their genetic fingerprints. She looks at two kinds of DNA in the samples : nuclear DNA , which shows variations from one animal to the other and the inheritance of traits ; and mitochondrial DNA , which is used to track female lineages. The dolphins at Sarasota were once thought to be a very localized, somewhat closed, social unit that mated within its own group. But Duffield discovered this year that males from neighboring bands come in to mate with the Sarasota females , and also that females outside the area interacted with the Sarasota males. The discovery was significant in that it showed how diverse - and healthy - the population is. If a cataclysmic environmen– tal accident happened in the waters off Sarasota, a closed social group could be wiped out, but an open one - as the dolphins appear to be - would have a much better chance at survival because animals from outside the area would help build back the population. Places such as Sea World in California also send samples to Duffield to learn more about the breeding habits of their own marine mammals. " It's amazing what we can see with genetics," said Duffield. "All of a sudden it's like walking into someone's living room. There are questions we never even knew we could ask that we're now ad– dressing." If Duffield has had such fascinating success in Florida, it may be because the area itself provides such a great natural laboratory: a place where a major species - the dolphins - spend a lot of time, and where local acceptance is toward cap– turing and taking samples from its various members. Biology professor Debbie Duffield The Pacific Northwest is a different story. One problem is there are no areas where animals other than seals and sea lions live consistently, so there is no way to routinely observe a group. One exception is the killer whale, whose social structure is being observed to some extent in Puget Sound and around Vancouver Island. Although the creatures are easy to capture and handle, Duffield said conservation groups have effectively imposed a "hands off' barrier against closer study. She has studied samples from Atlantic killer whales, but how they relate to killer whales in the Northwest cannot be known without samples taken from this region . "The equipment and the knowledge is there. It's ready. But politically it's very tough ," said Duffield. Eventually she may be able to do more genetic study among Northwest species, and when she does she is sure to discover what she has already found in Florida: that what people take for granted in the wild is often not true, and that reality can be proven under the microscope. D PSU 5