A. DNA Detective Work Tracks Hawaiian Spiders
Narrator: This is Science Today. A recent study of Hawaiian spiders documents how 16 species descended from a common ancestor about five million years ago. Biologist Rosemary Gillepsie of the University of California, Berkeley says studying the evolution of spiders on the Hawaiian Islands was particularly nice, since there's a built-in, chronological system there.
Gillepsie: You've got the oldest island at Kaui at five million years and then progressively younger islands, so you've got this whole progression of islands at different ages and you can see communities at different ages.
Narrator: Gillespie conducted DNA detective work to follow the radiation of the Hawaiian Long Spider from a single ancestor.
Gillespie: The whole phenomenon depends on very few colonists ever reaching the islands. So you get one animal getting there and there's nothing else there. So, it diversifies into multiple species to fill the empty niches in the communities there.
Narrator: For Science Today, I'm Larissa Branin.
B.
Future Alternatives to the Bionic Eye?
Narrator: This is Science Today. Researchers at the University of California, Berkeley, are working on ways to genetically engineer damaged retinal cells to be sensitive to light. Neurobiologist Richard Kramer says this technique has advantages over the most common approach of using a bionic eye, or rather, inserting electrodes in the optic nerve.
Kramer: Instead of having invasive electrodes at each cell that you want to regulate, the advantage of light is you can move the light beam around and there are sophisticated laser scanning devices that let you cover a very large area containing tens of thousands of neurons and impose patterns in a way that would be impossible with electrodes.
Narrator: Kramer's lab is collaborating with the optometry school at UC Berkeley.
Kramer: One challenge is going to be how you get the gene of interest into nerve cells in the retina and one way potentially to do that is by making viruses that infect nerve cells. We alter these viruses, so they're not capable of replicating themselves.
Narrator: For Science Today, I'm Larissa Branin.
C.
Ancient Mutation May Have Role in Disease Today
Narrator: This is Science Today. Mitochondria are the power plants of cells - helping control body temperature and the synthesis of ATP, a chemical form of energy. Researchers at the University of California, Irvine have discovered that key mutations in the mitochondrial DNA of migrating early humans helped them adapt to colder climates and may even play a role today in why certain people are prone to certain diseases. Study co-leader Douglas Wallace, explains mitochondria are the major source of oxygen radicals in the body.
Wallace: If your mitochondria are burning very hot and fast, then all of the calories are going to be making heat but if they're burning sluggishly, more of the calorie energy will go up in smoke and you'll get more oxygen radicals.
Narrator: Oxygen radicals kill off cells and lead to several age-related diseases.
Wallace: So what has been found is that the people with the mitochondrial DNA lineages that have the tendency to make more heat, they are protected against Alzheimer's and Parkinson's disease.
Narrator: For Science Today, I'm Larissa Branin.
D.
Drug Companies May Benefit from Bee Communication Research
Narrator: This is Science Today. A Brazil-based study of stingless bees offers new insight into communication strategies when competing for food. James Nieh, an assistant professor of biology at the University of California, San Diego, says bees use two main forms of communication: sounds or dances within the hive or by leaving scent markings outside to lead the rest of the hive to food sources.
Nieh: In the research we have been doing, we found this interesting strategy where some bees don't produce a complete trail. They in fact create a short trail that just points from the nest towards the food source. But only in the last 50 or so meters to the food source, so there is a big gap there. My idea is perhaps this makes it harder to find for other bees.
Narrator: Nieh says their research may benefit drug companies interested in the medicinal value of stingless bee honey and resin.
Nieh: Knowing more about their communication system, how they find these flowers and bring back these nectars, which may have medicinal compounds, may help us.
Narrator: For Science Today, I'm Larissa Branin.
E.
The Protein Folding Process: Something to 'FRET' About?
Narrator: This is Science Today. Illnesses such as Alzheimer's disease and even some cancers are a result of a protein folding process gone awry. These proteins are too small to view using a microscope, so to observe the process, scientists have long used a method called Forster Resonance Energy Transfer, or FRET. Physicist Everett Lipman, of the University of California, Santa Barbara, used FRET, along with their own innovation, to gain better insight into how proteins fold.
Lipman: The thing that we did for the first time - we used this microfluidic device. It's a set of channels that have been etched into a little silicon chip and then a piece of glass is bonded on the top. By using that little device, we were able to watch the protein at different times after the folding was started.
Narrator: Previous experiments could only observe molecules at random times.
Lipman: In this mixing device, we mix solutions together at one end of a big long channel and that starts the folding reaction. And then as we look at different places down the channel, we're looking at the proteins at different times after the folding reaction began and so we've been able to do a much more controlled experiment that way.
Narrator: For Science Today, I'm Larissa Branin.
