The nematode roundworm, Caenorhabditis elegans, is tiny— about the size of a comma on a printed page— and yet it can reveal a lot about human genetics according to Chemistry of Life Processes Institute’s latest member Erik Andersen.
Andersen, Assistant Professor of Molecular Biosciences, Weinberg College of Arts and Sciences, Northwestern University, studies genetic differences in C. elegans and relates them back to other populations to answer questions about evolution. He recently received an NSF Faculty Early Career Development Program Award to further his research.
“My lab is interested in populations of individuals and how we’re all different from one another,” says Andersen. “Why is it that humans are similar genetically, but we look different, we act differently, we have different disease propensities, we respond to drugs differently and so on?”
Andersen looks to worms for insights. When C. elegans encounter environmental differences like higher temperature or low food availability, some will develop normally into adults. Others, however, will adjust their development to save resources and enter an alternative larval stage where they can stay for months, says Andersen. He is interested in this developmental event where animals decide to alter development dependent on environmental conditions. Using quantitative methods, his goal is to find the genes involved in this process to better understand the role evolution plays in these decisions.
“Preliminary data show there are two regions of the C. elegans genome correlated with differences in this developmental decision and we know what the gene is in one of those regions,” says Andersen. “Essentially, it is a receptor that recognizes a pheromone.”
The roundworm’s small size allows Andersen’s lab to grow millions of animals within a few weeks. When worms are grown together, they secrete pheromones to talk to each other. The receptor recognizes one of the pheromones to let the other worms know how many worms are nearby. If a worm loses this receptor, then it no longer will respond to the pheromones of other worms in the vicinity. Because it never receives the signal to go in the other developmental direction, it will continue to grow to become an adult.
Humans possess the same types of molecules that make the same types of cell signaling decisions as the worm— the same pathways involved in growth and cancer.
“When you’re looking at the process of evolution,” says Andersen, “you are trying to understand what knobs it plays with to be able to change development in the presence of different environments, or developmental plasticity.”
An advocate for open science
Three years ago, when Andersen’s lab became overwhelmed with requests for data, he started the C. elegans Natural Diversity Resource, an open source repository of all wild C. elegans strains in the world and invited people from around the globe to send samples to his lab.
Participants include people he’s invited through social media and middle school and high school science classrooms. After receiving the worm samples, his lab determines their species and informs individuals and classrooms where they fall on the nematode “tree of life.” The lab also will give a brief lesson about nematode evolution and what the scientists have learned about the worms.
Nadia Singh, an associate biology professor at the University of Oregon who responded to Erik’s open call on Twitter, has collected worms from a variety of places and involved her children as well.
“I think we had the best luck in my brother’s backyard,” says Singh. “I took my kids to the grocery store, we bought some mushrooms and tomatoes, and came back and scattered them around my brother’s yard. A few days later, I bagged up the decomposing material and sent it to Erik. We didn’t actually get the worms out of the material— Erik does that in his lab.”
Singh says she wanted to help out because she believes science is a community enterprise.
“We often rely on people we haven’t even met to share ideas and resources. That shared spirit is what helps move science forward, and is part of what makes this career so fun.”
Andersen’s lab conducts big collections every four months with the goal of sequencing the genomes of a thousand individual strains by next year. Recently, they discovered a new species of Caenorhabditis from Hawaii and named it “oiwi,” a Hawaiian word that means “resident” or “local.”
“I’m a strong advocate for open science,” says Andersen. “I want to make all of what my lab does available to anyone for free.”
A big move
A new resident member of Chemistry of Life Processes Institute, Andersen looks forward to moving his lab to the Institute’s home in Silverman Hall by year-end.
“I’m excited to move over to Silverman so that we can integrate more with some of the groups that are within CLP,” says Andersen.
“I’m a firm believer in having people nearby who are able to share ideas in an informal way,” he says. “A lot of ideas and projects grow organically from small conversations, and I’m excited about being with CLP chemists and engineers in that way.”
by Lisa La Vallee