In a first, researchers have created a new strain of red-eyed mutant wasps using a novel gene editing technology. The wasps were created to prove that CRISPR gene-slicing technology can be used successfully on the tiny parasitic jewel wasps. The advance provides scientists a new way to study some of the wasp’s interesting biology, such as how males can convert all their progeny into males by using selfish genetic elements.
No one knows how that selfish genetic element in some male wasps “can somehow kill the female embryos and create only males,” said Omar Akbari, an assistant professor at University of California, Riverside in the US. “To understand that, we need to pursue their PSR (paternal sex ratio) chromosomes, perhaps by mutating regions of the PSR chromosome to determine which genes are essential for its functionality,” said Akbari.
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The new CRISPR technology allows scientists to inject components like RNA and proteins into an organism with instructions to find, cut and mutate a specific piece of DNA. The researchers can see how disrupting that DNA affects the organism.
The goal was to better understand the biology of wasps and other insects to find a way to control insects that destroy crops or spread diseases like malaria. The first step was figuring out how to use the CRISPR technology in such a small organism, something no one had ever done before, in large part because the work is daunting, Akbari said.
This is because jewel wasps lay their tiny eggs inside a blowfly pupa, which had to be peeled back to expose the teensy eggs. In the case of mutant wasps, the team decided to slice the genes that control the colour of the wasp’s normally black eyes.
“We wanted to target a gene that would be obvious, and we knew from previous studies that if the gene for eye pigmentation was knocked out, they would have red eyes, so this seemed like a good target for gene disruption,” Akbari said. “Big beautiful red eyes are something you would not miss,” he said.
“You have to use a very-very fine needle and a microscope and individually inject hundred to thousands of embryos, but in the end, we developed a protocol that can be used to cut the DNA in this organism and we showed that it works,” said Akbari. The cuts in the DNA created a mutant wasp with heritable traits, which means those red eyes will be passed down to all their offspring in the future – an important quality for researchers who are looking for a stable line of insects to study.
The research was published in journal Scientific Reports.