New Findings Confirm Darwin's Theory: Evolution Not Random (1/21/2008)

Soybean cyst nematode and egg

According to Darwin's theory of evolution, individuals in a species pass successful traits onto their offspring through a process called "deterministic inheritance." Over multiple generations, advantageous developmental trends - such as the lengthening of the giraffe's neck - occur.

An opposing theory says evolution takes place through randomly inherited and not necessarily advantageous changes. Using the giraffe example, there would not be a common neck-lengthening trend; some would develop long necks, while others would develop short ones.

Now, the findings of an international team of biologists demonstrate that evolution is not a random process, but rather occurs through the natural selection of successful traits. The collaborative study by researchers at the Technion-Israel Institute of Technology in Israel, the U.S, France and Germany is published in the November 2007 issue of Current Biology (vol. 17, pp. 1925-1937).

To settle the question about whether evolution is deterministic or random, the researchers used various tools - including DNA strand analysis and electronic microscopy - to study female sexual organ development in 51 species of nematode, a type of worm commonly used to better understand evolutionary processes.

When the researchers measured changes in 40 defined characteristics of the nematodes' sexual organs (including cell division patterns and the formation of specific cells), they found that most were uniform in direction, with the main mechanism for the development favoring a natural selection of successful traits, the researchers said.

"Since random development would not create such unifying trends, we concluded that the observed development was deterministic, not random," said Professor Benjamin Podbilewicz from the Technion Faculty of Biology.

The findings, which constitute a significant milestone in establishing and reaffirming the mechanism of Darwin's theory, will help in understanding how evolution works in all living creatures, said Podbilewicz.

Note: This story has been adapted from a news release issued by the American Technion Society

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