Dive Dry with Dr. Bill

#366: It's All in the Genes

Back in my Harvard days, I was an observer of something referred to as "Space Wars." Now this was the 60s, well before "Star Wars," and the phrase actually referred to office space rather than outer space. My biological focus was in the areas of ecology, evolution and biogeography, and my favorite professors included the likes of E. O. Wilson, Stephen Jay Gould and H. B. Fell. Harvard had always been strong in biology, especially in evolutionary biology. At the time it was focusing much attention on the relatively new area of molecular biology under Nobel Prize winner J. D. Watson, co-discoverer of the structure of DNA. Due to limited office space in the department, the "space war" broke out between the various biological disciplines and their professors. I later observed a similar "space war" in my graduate school days at UCSB.

Back then I found this disturbing, and still do today. Biology is a scientific endeavor that requires information from a wide range of perspectives: DNA and molecular genetics, cell biology, physiology, evolution, ecology, biogeography, etc. Without the pieces contributed by reach of these disciplines, we simply could not put together the puzzle that is our natural world. I was a strongly integrative biologist who saw the value in all these various disciplines. Of course it was the 60s and the era of anti-materialism, so the economic realities of providing comparable office space for all the professors' labs was not fathomable to me at the time.

I never took molecular biology with J. D. Watson while I was there. However, when I moved to Catalina in 1969 and had the responsibility of teaching "full spectrum" biology to my students, one of the things I did was to read J. D. Watson's The Molecular Biology of the Gene. I found it fascinating as it exposed another aspect of biology to me that I knew only a little about. I used much of the information in the book to create a class on evolution for my students which included the perspectives from molecular biology, classical evolutionary theory and modern theory. It became a very popular course for my better students, in part because of the incredible connectedness it created through geological time. Was the oxygen in your last breath formerly part of a dinosaur's muscle, or perhaps munched on by a Cambrian era helicoplacoid?

Now the closest I've come personally to actual molecular genetics was when my son appeared in my life nearly 10 years ago. Many men when approached with the possible news they were an unsuspecting father, might demand genetic testing to confirm this. Kevin's mother sent me pictures of him, which I forwarded to my sisters. All of them agreed with me... there was no need for DNA testing. Kevin was definitely mine. Yep, the poor boy had inherited my looks. Fortunately he hasn't let that handicap him too badly!

Recently several practical biological studies involving DNA testing have crossed my desk (or, more accurately, appeared in my computer monitor). I thought these would be interesting to share with my readers as examples of how DNA research has entered mainstream society, as well as improving our ability to answer tough ecological questions. Once again, the information added by these studies allows us to piece together even more of Nature's puzzle.

The first study involved two recent high school graduates, Kate Stoeckle and Luisa Strauss, who decided to take samples of the "sushi" served in some New York restaurants and sold in grocery stores there. They wanted to use DNA testing to determine whether the "sushi" was indeed from the fish it was marketed as. Fortunately, the father of one of the girls was a scientist with expertise in DNA techniques. Just as fish (and other food items) are identified in stores by a bar code for rapid computer recognizition at the cash register, they are also given a genetic "bar code" in the form of their DNA. Scientists can tell whether the "tuna" on your dinner plate is actually tuna... or not.

The results from the samples the girls took revealed that many of them were not properly identified as the right fish. Half of the samples from restaurants and six out of the 10 samples from grocery stores were in error. What was sold as tuna in one case was actually much cheaper tilapia from Mozambique! "Flying fish" roe was actually eggs from smelt (I thought I "smelt" something fishy there). Red snapper was used instead of Atlantic cod. These "misidentifications" were not thought to be by the restaurants and stores themselves, or by the fishers that caught them, but somewhere within the distribution channels in between. Another researcher found that more than half of the "grouper" and "snapper" served in Florida restaurants was actually much cheaper catfish or tilapia, but he felt these were cases of fraud by the restaurants.

Other similar studies have shown "tuna" in some cases to be escolar, a more common fish which can cause diarrhea and other medical problems. Some tuna turned out to be bluefin tuna which has become endangered by overfishing to the point where only 10% of the pre-fishing stocks remain. I guess "Truth in advertising" needs to be tested genetically these days. There is talk about developing a hand-held DNA bar coding device that restaurant patrons and grocery store shoppers could use to verify they are getting what they pay for. I guess certain foods may have to be scanned twice... once by the customer and then by the grocery checker. It reminds me of the days when one could buy "sea scallops" that were actually cut out of stingray "wings." Of course a trained marine biologist like me could tell the difference just by the way the muscles fibers were oriented... but they were usually cheaper!

Another interesting application of fish DNA testing comes from a recent paper published by Dr. Mahmood Shivji, Director of the Guy Harvey Research Institute in Ft. Lauderdale, FL. Dr. Shivji and his co-researchers had samples taken of hammerhead shark fins offered for sale in Hong Kong markets and tested using DNA methods. They were able to determine not only the species of hammerhead involved, but in the case of the scalloped hammerhead, the geographic locations from which they were taken. It was determined that 21% of the fins tested came from waters off the coasts of the United States, Belize, Panama and Brazil where this species has been categorized as endangered by the IUCN (International Union for the Conservation of Nature). Talk about excellent detective work! Perhaps it will spawn a brand new TV show... CSI Underseas.

Now I've always been a fan of Eastern cultures ever since my father returned from a business trip to Japan in 1960. However, the factory ships that have been sent out by countries such as Japan, China and Korea to harvest fish and invertebrate resources from the global oceans are an ecological nightmare and a practice I cannot support. Even during the pre-World War II era, such vessels overharvested areas like the Sea of Cortez causing John Steinbeck and Ed "Doc" Ricketts to comment sadly on this over-exploitation. Such factory ships have been found more recently with as many as 10,000 marlin carcasses in their holds! Is it any wonder striped marlin have declined in our waters? Of course western nations like the United States have not been innocent in all this either.

China's fascination with the once royal menu item of shark fin soup has been one focus of the environmental movement's activism against these practices. Estimates suggest as many as 75-100 million sharks are taken each year for various purposes. I've offered to do my scientific duty to fight this ecologically disastrous fishery by employing the single culinary skill I possess. I've extended an open invitation to any intelligent single Asian female to come up to my home and sample my only masterpiece... my Thai green curry. I'm sure it, and my extensive charm, will quickly convert them to this much more ecologically sound dish. No takers? The story of my life!

© 2009 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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The unknown fish dinner, the unknown sushi snack, the known (sadly) shark fin soup and a scientist
trying to guess which fish they really are using DNA

This document maintained by Dr. Bill Bushing.
Material and images © 2009 Star Thrower Educational Multimedia