Narrator: It seems we're still a long way from Jurrasic Park. This is Science Today. Some time ago, scientists reported isolating dinosaur DNA. But before we think about cloning baby dinosaurs from it, we should make sure it's the real thing, according to paleontologist Charles Marshall of UCLA. The problem is that genetic material is more and more questionable the older it is. If it's thousands of years old, it's probably OK. Millions of years or older, and it might well be contaminated with more modern material.
Marshall: At this point people still doubt the authenticity of a lot of the ancient DNAs. From Egyptian mummies and things like that, they seem to be quite clear. But the recent dinosaur DNA that was reported turns out to be human DNA contaminants presumably from the technicians involved in the work.
Narrator: Far from wanting to raise dinosaurs, Marshall and his colleagues are simply interested in tracing the ancestry of life what species descended from what. Someday they may be able to compare ancient DNA with the modern stuff but not yet.
Marshall: At this point I don't think ancient DNA has added an awful lot to our deep understanding of the evolution of life.
Narrator: For Science Today, I'm Steve Tokar.
Narrator: This is Science Today. Are men's and women's brains different? Neurobiologist Roger Gorski of UCLA says rats provide an intriguing clue. Basically, rat brains start out essentially female in structure.
Gorski: So for a brain of an animal to develop functional and structural characteristics that are typical of the male of the species, his brain must be exposed to testicular hormones.
Narrator: And if you treat young male rats so that they can't respond to male hormones, they'll be completely feminized.
Gorski: So you can have a genetic male with actually normal male genitalia for a rat but his brain is female. He will exhibit female levels of female sex behavior for example. He will be less aggressive. He will play differently. He will have perhaps different stategies in learning maze tasks and so on.
Narrator: Gorski says there are humans who, for one reason or another, have been similarly affected. However...
Gorski: No one has looked at brains of these people as far as I know yet to see if brain structure has been changed.
Narrator: But he thinks it would be a good idea. For Science Today, I'm Steve Tokar.
Narrator: This is Science Today. The earth's population is growing every day. How do you feed all those hungry people without destroying the environment with agricultural chemicals? Agricultural expert Ted Hullar of the University of California, Davis says the answer is more international collaboration between scientists. And more than that...
Hullar: ...collaboration of the scientists with those who would use the information, like the farmers themselves.
Narrator: And that, in turn, means a need for more agricultural extension services.
Hullar: Around the world, we don't have in place as many of the extension and workingwiththefarmers arrangements as we should have. So that's clearly a need, that has to be developed at the same time as we develop these research relationships.
Narrator: But Hullar cautions that we can't just go into a country and tell its farmers what to do.
Hullar: We, let's say in the United States, have to be careful about going into another country and saying to them, well we want to develop ways of working with your farmers. I mean would we want people from another country coming to us in the United States and saying, we want to work with your farmers? Oh no, we'll work with our own farmers, you work with us.
Narrator: For Science Today, I'm Steve Tokar.
Narrator: The earth is turning an ear to outer space. This is Science Today. Astronomer Dan Werthimer of the University of California, Berkeley manages a most unusual project.
Werthimer: The project is called SERENDIP. It's looking for other civilizations. We are looking for radio signals coming from those other civilizations.
Narrator: The project is using earth's largest radio telescope to catch not only radio, but all kinds of electronic signals from outer space. Thanks to computers and sophisticated software, scientists can monitor millions of channels at once.
Werthimer: They might send us a message on purpose, but they might just send off radio or television or radar or something that they're using for their own internal purposes, much like we send off all kinds of radio and television that are now leaving the earth. The early shows that left the earth, I Love Lucy, Ed Sullivan, those early television shows have now gone out past several thousand stars.
Narrator: In the same way, project SERENDIP hopes to catch reruns from other stars. Werthimer is confident that we'll run across a signal from another civilization in his lifetime. For Science Today, I'm Steve Tokar.
Narrator: This is Science Today. In the United States, as elsewhere in the world, agricultural land is going out of use faster than it's being replaced. Yet we have more people to feed. How can we grow enough food on less land? Shu Geng, a professor of agronomy at the University of California, Davis, says there are a number of possible solutions. One simple way would be to eat less food.
Geng: For example, in the United States sometimes we might think that we probably overeat, that we eat too much. And maybe it is time to look at do we need to consume that much food or not?
Narrator: Geng identifies one way that we can cut down on food consumption without giving up nutrition.
Geng: When we say we are overeating, most people believe we are overeating in terms of meat. Meat production costs more than eating the primary products, like the grain you have to feed the animals.
Narrator: Geng says it costs up to ten times more to feed plants to eat animals and then eat the animals than it costs to eat plants directly. For Science Today, I'm Steve Tokar.
Produced by Steve Tokar of Communications Services, Office of the President, for the CBS Radio Network, (510) 987-9203, steve.tokar@ucop.edu