DURHAM, N.C., July 31 (UPI) -- New research suggests starved worms generate smaller, hardier offspring for at least three generations. The findings, detailed in the journal Genetics, prove that famine can have long lasting effects.
Nematode worms take an all-or-nothing approach to life. When things good, things are really good. In boom times, the worms' reproduction booms. But the occasional famine can be devastating to nematode worm populations.
In studying the small percentage of worms that survive famine events, researchers at Duke University realized starved worms pass on survival traits to their offspring. Although genes aren't altered, gene expression changes.
Duke biologist Ryan Baugh and his team of researchers starved thousands of nematode larvae, just after hatching. These worms ended up smaller and less fertile. And surprisingly, so did their offspring.
The offspring of the previously malnourished worms turned out to be smaller, less fertile and more likely to be male -- as opposed to the usual hermaphroditic, self-fertilizing form. But they were also more likely to survive future famines and better resistant to heat.
It turns out, the species' ability to ramp up their biological processes during boom times can also work in reverse. They can also ratchet down key physiological mechanisms like metabolism and reproductive behavior. By producing more males, scientists believe they're insuring greater genetic diversity in the face of a shrinking population.
"They have a memory of famine," Baugh explained in a press release.
The process by which genes are expressed -- turned on and off in varying combinations -- is called epigenetics. Baugh and his colleagues aren't sure of the epigenetic mechanism responsible for worms' adaptations, but they hope further studies will help them find out.
Research into the long-term effects of human famine is understandably difficult. Human children, of course, can't be starved for science. But scientists say animal studies, like this one, can offer insights into the long-term effects of malnourishment on human generations.