MAISRC researchers are developing a synthetic incompatibility method that could control populations of pest or invasive species and prevent genetically modified aquatic organisms from spreading transgenes to wild populations. This technique involves genetically altering males of the invasive species and releasing them into the wild, resulting in sterile offspring and eventual population control. This method shows promise as a species-specific, broadly applicable, and cost-effective solution for population control. This project is in its fourth stage.
Project update:
MAISRC researchers made progress in developing genetic control methods for invasive common carp. They developed a new method to enrich genetically modified sperm, which will make it easier to evaluate whether genetic approaches can produce the desired changes in offspring sex ratios. Researchers also successfully transplanted reproductive cells between common carp, with transplanted cells developing into healthy-looking ovaries and eggs in a host fish. This means there is potential to use surrogate fish to produce reproductive cells from genetically modified fish. Researchers also built and began testing a camera-based system to monitor carp behavior.
Phases
Phase I
Project manager: Michael Smanski
TImeline: 2016-2018
The foraging habits of the invasive common carp, Cyprinus carpio, degrade water quality, reduce vegetative cover and waterfowl numbers, and diminish the ability of lakes to absorb nutrients from agricultural runoff. Current control methods have been insufficient, necessitating improved strategies. The overall goal of this phase by MAISRC researchers is to demonstrate a novel approach for controlling aquatic invasive species using invasive carp as a proof-of-concept. Success would pave the way for applying this method to other aquatic invasive species (AIS).
Several major obstacles had to be overcome in this project to establish the foundation for genetic biocontrol of invasive carp. These included developing husbandry for year-round carp spawning in the MAISRC Containment Lab, demonstrating transgenesis of C. carpio, testing genetic reagents in a model laboratory fish needed to engineer carp, and conducting a survey to gauge public perceptions of carp genetic biocontrol. The researchers accomplished these goals within a one-year no-cost extension to the project funding.
As of late 2021, researchers at MAISRC performed several rounds of carp spawning in the MAISRC Containment Lab. Each successive attempt showed increased success: the first attempt resulted in poor spawning, the second in premature but successful spawning (an unexpected early morning spawning prevented a transgenesis attempt), and the third resulted in verified transgenic carp.
An agent-based simulation model for carp genetic biocontrol has been developed to compare several biocontrol approaches. A public opinion survey was conducted via two methods: an email to the MAISRC listserv in Fall 2018 and at the Driven to Discovery building during the 2019 MN State Fair, collecting over 1,300 responses. The survey revealed that Minnesotans are more likely to support biocontrol over chemical control, but not as much as physical methods like trapping and netting. Among biocontrol methods (predator release, pathogen release, genetic biocontrol), genetic biocontrol was the most favored. Perceptions of the relative efficacy of different methods correlated more strongly with comfort levels than perceptions of risks.
Phase II
Project manager: Michael Smanski
TImeline: 2022-2024
The overall goal of this phase is to responsibly advance technology development related to the genetic biocontrol of aquatic invasive species (AIS), specifically common carp. In the past six months, researchers have made substantial progress on many fronts. They have continued to improve carp spawning, in vitro fertilization, and transgenesis procedures. Several different transgenic carp have been created, the first of which have reached sexual maturity and have been outcrossed to wildtype carp to test their efficacy.
Progress has also been made on surrogate host technologies, which promise to accelerate research and development efforts in common carp and other AIS. In this regard, researchers have improved the husbandry, spawning, and transgenesis protocols for fathead minnows, which serve as the surrogate host. Additionally, they have demonstrated transgenic labeling of common carp primordial germ cells. Currently, researchers have begun testing the complete primordial germ cell transplantation process from common carp to fathead minnows.
Lastly, the social outreach objective of the project continues with the hosting of a second AIS Genetic Biocontrol Technology Readiness Level workshop. Although there is still some ambiguity among stakeholders and rights holders about the timing and type of social engagement and outreach in the Technology Readiness Level (TRL) classification system, researchers are preparing a manuscript to communicate the results of the 2022 and 2023 workshops.
Phase III
Project manager: Michael Smanski, Professor, Department of Biochemistry, Molecular Biology, and Biophysics
Co-PI: Toby Warden
Research team:
Julie Badger, Graduate scholar
Leland Feist, Graduate scholar
Colby Johnson, Graduate scholar
Funded by: MAISRC and the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources
Timeline: 2024-2025
Research findings:
MAISRC researchers developed more than 20 genetically engineered carp lines, primarily designed to produce offspring with a male-biased sex ratio, and developed a new fluorescence-based method to identify and enrich genetically modified sperm. The research also led to the unexpected discovery that common carp and fathead minnows can produce viable hybrid offspring, called “marps.” Researchers are investigating whether these hybrids could serve as surrogate hosts and support a novel, non-GMO approach to carp control in which surrogate males produce minnow sperm that could reduce carp reproduction. Together, these findings advance the development of new genetic approaches for managing invasive common carp while identifying important technical questions that must be resolved before they can be used in the field.