Broadcast: December 16, 2003
This is Science in the News, in VOA Special English. I'm Bob Doughty.
And I'm Sarah Long. This week -- a research plan for autism ... and, a look at how a small animal can have a big influence on future forests.
Also ... a small fish lands in the news for a reason that will be easy to see.
Autism is a brain disorder. It first appears in children. The National Institute of Mental Health in the United States says autism usually affects three abilities. These are the ability to communicate, form personal relationships and react in a normal way to the environment.
Scientists know that genetics play a part, but much else remains a mystery.
The United States government has announced a ten-year plan to study autism. The plan is called a "roadmap" to guide research by government and private scientists. The Department of Health and Human Services and the Department of Education organized a conference last month in Washington. The meeting brought together autism experts, activists and government officials.
The level of disability among autistic people can differ greatly. Some may have complete command of speech and no lack of intelligence. Others may not speak at all. Still others may be mentally slow, or unable to stop themselves from repetitive actions.
Autistic people may have an unusual ability to remember numbers and facts -- people's birthdays, for example.
Autistic children often seem in their own world. A young baby may not look at people. A child may act aggressive suddenly.
Normal children generally are uncomfortable with strangers. Or they might cry when their parents leave them. But a child with autism might not seem to show interest in other people.
Parents of autistic children usually notice communication and language problems in their child by the age of three. Autism experts say about half of children identified as autistic never learn to speak.
Others learn to speak, but the ability may develop later than normal. Speakers may not form meaningful sentences. Or they might simply repeat what others say.
In the United States, many children with autism attend school with other students, although with special education. How well people with autism do in life depends, of course, on the severity of their condition. But autism organizations agree there are too few services to help.
Officials in the United States say the roadmap for research aims to change that. It calls for federal agencies, autism organizations and researchers to work together closely for the next ten years.
One goal is to find the cause of autism. Another is to develop a test to identify the disorder in young babies.
Experts generally agree that early intervention is important, even with the limited ways to deal with autism. For example, there are special teaching methods for children.
The Food and Drug Administration in the United States has not approved any medicines for autism. But doctors may give drugs used to treat other disorders. These can help control repetitive actions, for example, or aggression.
The roadmap for research also calls on medical researchers to seek ways to prevent at least some kinds of autism.
The government says autism affects about one to two people in every thousand. Out of almost three-hundred-million Americans, that would be as many as about six-hundred-thousand cases.
But the Autism Society of America says an estimated one-and-a-half-million Americans have some form of autism. And the group says the problem is growing. Experts, though, say greater public interest and better identification methods may have helped increase the number of cases reported.
In January, pet stores in the United States are to begin selling a new kind of fish. It is a zebra fish. Zebra fish are not new. What is new is people will not need a lighted fish tank to see it in a dark room. This fish lights up red. It is called the GloFish. And it is the first creature to be sold as a genetically engineered house pet.
Scientists in Singapore developed the fish to use in searches for environmental poisons in waterways. They took a color gene from sea coral and placed it into zebra fish egg cells.
A genetically changed zebra fish produces babies that also glow.
Scientists often use zebra fish in genetics work. The fish cost less and are easier to care for than mice and other laboratory animals. Scientists say zebra fish are especially helpful in a new science called proteomics, or post-genomics. It deals with the duties of proteins as they relate to genes.
Fluorescent fish also have been helpful in the study of disease and physical development. And now some people want them as pets. Fluorescent fish went on sale earlier this year in Taiwan.
Recently a company in the United States decided to raise and sell fluorescent zebra fish. Yorktown Technologies is based in Texas. GloFish are raised at a fish farm in Florida.
The marketers say the fish are just like normal zebra fish, except they glow. They say the fish are not harmed and are as healthy as other zebra fish.
Not everyone thinks GloFish are such a bright idea. California has decided not to permit sales in that state. California bans the sale of animals created by genetic engineering except in some cases. Exceptions are made for scientific purposes, or if there is proof it will not harm the general animal population.
Scientists told the California Fish and Game Commission there was no danger if the GloFish escaped into waterways. But the chairman said it was not a question of science. He said selling genetically engineered fish as pets is wrong.
Greenpeace and other groups say the federal government should control sales of the GloFish. Last week the government said no.
Winter begins in the north on December twenty-second. People and animals have been doing what they always do to prepare for the colder months. Squirrels, for example, have been busy gathering nuts from trees. Well, scientists have been busy gathering information about what the squirrels do with the food they collect.
They examined differences between red squirrels and gray squirrels in the American state of Indiana. The scientists wanted to show how these differences could affect the growth of black walnut trees.
The black walnut is the nut of choice for both kinds of squirrels. The black walnut tree is also a central part of some hardwood forests.
Rob Swihart of Purdue University did the study with Jake Goheen, a former Purdue student now at the University of New Mexico. The findings are in the Canadian Journal of Zoology.
The two researcher estimate that seven times as many walnuts grow when gathered by gray squirrels as compared to red squirrels. Gray squirrels and red squirrels do not store nuts and seeds in the same way. Gray squirrels bury nuts one at a time in a number of places.
But they rarely remember where they buried every nut. So some nuts remain in the ground. Conditions are right for them to develop and grow the following spring. Red squirrels, however, store large groups of nuts above ground. Professor Swihart calls these "death traps for seeds."
Gray squirrels are native to Indiana. But Professor Swihart says their numbers began to decrease as more and more forests were cut for agriculture. Red squirrels began to spread through the state during the past century.
The researchers say red squirrels are native to forests that stay green all year, unlike walnut trees. They say the clearing of forest land for agriculture has helped red squirrels invade Indiana. Jake Goheen calls them a sign of an environmental problem more than a cause.
SCIENCE IN THE NEWS was written by Caty Weaver and George Grow. Cynthia Kirk was our producer. This is Bob Doughty.
And this is Sarah Long. Join us again next week for more news about science, in Special English, on the Voice of America.