Northwestern Prof. publishes research on roundworms, lends evidence to Darwin’s hypothesis


Source: Erik Andersen

Roundworms magnified under a microscope. Prof. Erik Andersen’s study uses them to draw major findings.

Amy Li, Campus Editor

Erik Andersen, a Northwestern associate professor of molecular sciences, lent some of the first evidence to Charles Darwin’s 1859 hypothesis that natural selection acts similarly to domestication using new research that monitors roundworm reproductive processes.

Andersen’s study, published on Sept. 23 in the journal of Nature Ecology & Evolution, uses one millimeter-long roundworms, C. elegans, to investigate how the nematode gambles between feeding within its existing environment or undertaking a dangerous journey to a new location that may promise more food.

“It sounds like a simple decision, but it’s one of those decisions that every organism in nature has to decide,” Andersen said.

Andersen found that the nematodes’ evolution in nature parallels their growth in a laboratory setting from a 2011 study by Stanford University’s Patrick McGrath, published in Nature, thereby discovering convincing evidence for Darwin’s theory in his book, “On the Origin of Species.”

“The evolution of traits is rarely connected to exact genes and processes,” Anderson wrote in a University release. “We offer a clear example of how evolution works.”

Darwin’s ideas focused on exotic bird systems, which are difficult to regulate in a laboratory and in nature. However, C. elegans, with a relatively simple genetic system, makes testing hypotheses on genetic crosses and the function of genomes more feasible.

The discovery that C. elegans could be an effective and versatile system to use in a myriad of research on genetics was a primary motivating factor for first starting his lab, Andersen said.

“(Using C. elegans), we can easily do genetic crosses and understand how the genome works, whereas if we were doing this in pine trees, elephants or humans, it would take decades to get the same answers,” Anderson said.

Humans need about 20 years to cycle through a single generation. By contrast, C. elegans take only around 3.5 days to grow.

Andersen’s lab, which employs 17 full-time staffers and 14 undergraduate students, is working on a variety of different research projects testing gene characteristics and responsiveness using the nematode.

The lab currently uses nematodes to how genes lead to differences in chemotherapeutic responses. The lab is also studying the evolution of parasitic nematodes, which affect two billion people across the world every year.

“We want to understand how drugs used to kill these parasites also work with C. elegans, and we can then learn about what genes respond to resistance against these drugs,” Andersen said.

The molecular biologists in the lab used a combination of laboratory experiences, computational genomic analysis and field work to show that natural selection acts on signal-sensing receptors, rather than the later parts of the genetic process, according to a Northwestern release.

“The evolutionary principles outlined in the study — they come to play in many other projects in the lab,” Andersen said.

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