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Assistant Professor Austen Barnett Teams with Researchers from Harvard, Japan to Study Cricket Genomes

by Janelle Hill Sep 30, 2021

What’s in a cricket’s genome? The answer, as Austen Barnett’s latest research shows, is surprising.  

Barnett, Ph.D., assistant professor of biology, recently collaborated with researchers from Harvard University and Japan on a published research paper looking at the genomic evolution of crickets. 

The paper begins by noting the difference between the hemimetabolous and holometabolous groups of insects.

“A lot of the insects that people are familiar with are holometabolous,” says Barnett. “They go through complete metamorphosis, so think of a caterpillar transforming into a butterfly. But ancestrally, insects were hemimetabolous. Hemimetabolous insects emerge from the egg looking similar to what they will look like as adults.”

Crickets are considered hemimetabolous, and, according to Barnett, there’s little research devoted to the genomic evolution of these insects. The team examined two cricket genomes. Barnett collected and sequenced DNA and RNA from the cricket Gryllus bimaculatus. The group then put the genome, or genetic code, together and annotated, or labeled, it. 

The results? They found that hemimetabolous insect genomes aren’t just big, they’re humongous. Barnett says hemimetabolous insects can have up to four times the amount of DNA in a cell compared to their holometabolous counterparts. He compares it to extra baggage that doesn’t hurt the insect or affect its fitness. 

“We found that there’s a lot of transposable element activity, or pieces of DNA that literally jump around the genome,” he says. “They’re actually ancient viruses that don’t know they’re not viruses anymore, but they still act like viruses. Through that activity, you actually increase the DNA that’s in there.”  

In addition to that extra baggage, Barnett and his colleagues found that the crickets also have duplicate copies of what are known as pickpocket genes, which are used in neural responses to outside stimuli. They believe those genes might play a role in the evolution of cricket courtship, including their “chirping” behavior.

Barnett’s research students also learn first-hand how to sequence and annotate genomes. This semester, they’re looking at specific genes of arachnids. According to Barnett, there’s no telling where this type of research might lead. 

“We’ve been able to do a lot in medicine based on things you wouldn’t think of,” he says. “We use the green fluorescent protein for biomedical research. Where did that come from? Someone was trying to figure out why jellyfish are glowing green. The more that we learn about nature, the more we can apply it.”