Wasp venom holds clues on how genes get new jobs

June 22, 2017, University of Rochester
Tiny parasitic Jewel Wasps and their rapidly changing venom are the subjects of a new study by researchers in the University of Rochester's Werren Lab. Credit: University photo / J. Adam Fenster

Amid the incredible diversity of living things on our planet, there is a common theme. Organisms need to acquire new genes, or change the functions of existing genes, in order to adapt and survive.

How does that happen?

A common view is that duplicate, with one of the copies picking up a new function while the other copy continues to function as before.

However, by studying tiny parasitic Jewel Wasps and their rapidly changing repertoires, the Werren Lab at the University of Rochester has uncovered a different process that may be widespread in other species as well.

The process involves co-opting single copy genes to take on new functions. In some cases, these genes appear to continue their previous function as well, in other parts of the wasp's anatomy besides the venom gland. The findings are published in Current Biology.

"It is almost as if they are now moonlighting," says John (Jack) Werren, professor of biology. "They've got a day job, and then take on a night job as well. Over time, if the night job works out, they may give up the day job and evolve as a venom specialist. However, in other cases we have found that they stop moonlighting as venom genes but appear to retain their day job."

In a study published in Current Biology on June 22, the lab of Professor John Werren at the University of Rochester describes how four closely related species of parasitic wasps change their venoms rapidly in order to adapt to new hosts, and proposes that co-option of single copy genes may be a common but relatively understudied mechanism of evolution for new gene functions, particularly under conditions of rapid evolutionary change. Credit: Matthew Mann/ University of Rochester

How is a gene co-opted? And what determines which job (or combination of ) it performs? In the case of Jewel Wasps, the process called gene regulation is key. As the researchers explain, the rapid turnover in venom genes is accomplished mostly by changes in regulatory regions adjacent to the genes.

These control how the genes are expressed—that is, whether the genes are turned "on" or "off" in different tissues. When a gene is turned on, it provides instructions for manufacturing proteins. When it's turned off, it provides no such instructions.

"Co-option of single copy genes can be a more rapid mechanism for adapting to a new environment because it does not require the gene to be duplicated first," notes Ellen Martinson, a co-lead author and postdoctoral research associate in the Werren Lab.

"In essence, these are recycling their genes for new functions," says co-lead Mrinalini, a former postdoc in the Werren Lab who has since joined the National University of Singapore, where she studies snake venoms.

Female parastic wasp injects venom in fly pupa host. Credit: Michael E. Clark

The group—which also includes two other researchers at the University of Rochester, Yogeshwar Kelkar and Ching-Ho Chang—studied four closely related species of Jewel Wasps. The wasps lay their eggs on the pupae of other insects, after first injecting the pupae with venoms that manipulate the metabolism of the host in ways that make the environment more conducive to their developing young.

Using transcriptome and proteome sequencing, the researchers found that more than half of the venom components in the parasitic wasps resulted from single copy genes that had been co-opted without being duplicated. The composition of the venoms can change quickly, allowing the wasps to adapt to different hosts. For example, even closely related species can differ by up to 40 percent of their venom repertoire.

The group proposes that co-option of single copy genes for new function is not just restricted to parasitoid venoms. Co-option may be common in nature, particularly when organisms are evolving rapidly to changing environments.

Parasitoid venoms, like those from the Jewel Wasp, have been developed into new pharmaceuticals and drugs. “It’s a vast potential resource for new drug discovery,” says professor Jack Werren. Credit: University photo / J. Adam Fenster

With regards to parasitoid venoms, there may be an added benefit, says Werren. "The great diversity of parasitoid venoms and abundance of these species (estimates run as high as 600,000 parasitoid species on earth), combined with the fact that parasitoid venoms have evolved to manipulate metabolic processes, suggests that they are potentially an immense untapped cornucopia for drug discovery."

Explore further: Newly discovered virus affects sex ratio of insect-killing wasps

More information: The Evolution of Venom by Co-option of Single-Copy Genes, Current Biology (2017). 10.1016/j.cub.2017.05.032 , www.cell.com/current-biology/f … 0960-9822(17)30568-7

Related Stories

Scientists find a key to growth differences between species

February 23, 2012

The tiny, little-noticed jewel wasp may provide some answers as to how different species differ in size and shape. And that could lead to a better understanding of cell growth regulation, as well as the underlying causes ...

Team proposes new model for snake venom evolution

December 8, 2014

Technology that can map out the genes at work in a snake or lizard's mouth has, in many cases, changed the way scientists define an animal as venomous. If oral glands show expression of some of the 20 gene families associated ...

Recommended for you

The powerful meteor that no one saw (except satellites)

March 19, 2019

At precisely 11:48 am on December 18, 2018, a large space rock heading straight for Earth at a speed of 19 miles per second exploded into a vast ball of fire as it entered the atmosphere, 15.9 miles above the Bering Sea.

Revealing the rules behind virus scaffold construction

March 19, 2019

A team of researchers including Northwestern Engineering faculty has expanded the understanding of how virus shells self-assemble, an important step toward developing techniques that use viruses as vehicles to deliver targeted ...

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.