主题：我国部分地区大老鼠绝迹 被指与转基因玉米有关 -- 破鱼

In the research report, scientists from the University of Utah show that rat fetuses receiving poor nutrition in the womb become genetically primed to be born into an environment lacking proper nutrition.

As a result of this genetic adaptation, the rats were likely to grow to smaller sizes than their normal counterparts. At the same time, they were also at higher risk for a host of health problems throughout their lives, such as diabetes, growth retardation, cardiovascular disease, obesity, and neurodevelopmental delays, among others. Although the study involved rats, the genes and cellular mechanisms involved are the same as those in humans.

The scientists made this discovery through experiments involving two groups of rats. The first group was normal. The second group had the delivery of nutrients from their mothers' placentas restricted in a way that is equivalent to preeclampsia. The rats were examined right after birth and again at 21 days (21 days is essentially a preadolescent rat) to measure the amount of a protein, called IGF-1, that promotes normal development and growth in rats and humans. They found that the lack of nutrients caused the gene responsible for IGF-1 to significantly reduce the amount of IGF-1 produced in the body before and after birth.

The FDA contends that GM foods are substantially equivalent to non-GM foods, and therefore not subject to more stringent labeling.

How prevalent are GM crops? What plants are involved?

According to the FDA and the United States Department of Agriculture (USDA), there are over 40 plant varieties that have completed all of the federal requirements for commercialization (http://vm.cfsan.fda.gov/%7Elrd/biocon). Some examples of these plants include tomatoes and cantalopes that have modified ripening characteristics, soybeans and sugarbeets that are resistant to herbicides, and corn and cotton plants with increased resistance to insect pests. Not all these products are available in supermarkets yet; however, the prevalence of GM foods in U.S. grocery stores is more widespread than is commonly thought. While there are very, very few genetically-modified whole fruits and vegetables available on produce stands, highly processed foods, such as vegetable oils or breakfast cereals, most likely contain some tiny percentage of genetically-modified ingredients because the raw ingredients have been pooled into one processing stream from many different sources. Also, the ubiquity of soybean derivatives as food additives in the modern American diet virtually ensures that all U.S. consumers have been exposed to GM food products.