Saving the Whales Through DNA

Last night, I went to hear Dr. Stephen Palumbi of Stanford talk about how his research group studies whale DNA to better understand the current populations of many types of whales, and to assist in their protection. Basically, he extracts DNA from small samples of tissue and measures the genetic variation in it. Knowing the equations for variation based on factors such as population size and mutation rate, he can calculate the expected population size for a given amount of genetic variation.

Results so far indicate that many whale species have far too much genetic variation for the small population sizes we see today. Conclusion: There used to be more whales-- a lot more whales. This supports the need to protect them more vigorously. It also stands as some evidence against current claims that whale populations, which has been slowly rising since whale protection legislation was enacted, might be as they are because the oceans have already reached carrying capacity, so whales are food-limited-- ie, they have already recovered as much as they are supposed to.

Palumbi looks at fish too and has seen some similar results. He thinks his data show that humans have eaten many, many fish and that the oceans could really support greater populations (and indeed did so in the past).

Another thing Palumbi does is create short science videos to be viewed online. There are a bunch of such videos at Microdocs.org. All the ones Palumbi's lab have contributed to Microdocs are listed here (he calls it "Short attention span science theater"). In particular, I recommend the one about testing the DNA of store-purchased "Pacific red snapper." Caveat emptor! You might not be getting a red snapper-- check it out (just 5 minutes, and packed with interesting facts. He even has a famous chef assisting him in the DNA analysis).