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Gene Drive Modeling Conference

    June 11, 2019-June 12, 2019
    740 Fifteenth Street NW
    Washington, DC, USA

Gene drive technology refers to any of a set of similar mechanisms that can be engineered to drive inheritance of an allele through a population through higher transmission from parents to offspring than predicted by Mendelian inheritance. The potential applications of this technology in agriculture are many and include uses for pest, disease, and weed control. Because field-testing of gene drives in the environment is problematic, mathematical modeling of gene drives will be important in understanding their potential environmental impacts. The Agriculture & Food Systems Institute organized the Gene Drive Modeling Conference to bring together regulators, risk assessors, modelers, and biologists who understand gene drive technology to discuss the applicability of models for the environmental risk assessment of gene drive organisms, as well as to identify criteria for establishing the quality of information that will be needed to inform future risk assessments of gene drives.

The conference was made possible through a grant from the USDA’s National Institute for Food and Agriculture Biotechnology Risk Assessment Research Grants Program for the purpose of fostering a discussion between U.S. regulatory agencies and scientists in the field of modeling for gene drive research. 

Participants at the Gene Drive Modeling Conference (June 11, 2019)

Gene Drive Modeling Webinar Series

Leading up to the conference, a series of online seminars were organized to provide baseline information and facilitate discussions during the event. View recordings of these three webinars by clicking through the tabs below.

Adding Biology to Mathematical Models of Gene Drive Spread in Populations: A Case Study of Engineered Underdominance

Dr. Sumit Dhole

Department of Entomology & Plant Pathology, North Carolina State University

Understanding how gene drives would behave in natural populations is critical if this tool is ever to be used for the variety of applications that it can potentially serve. However, a multitude of factors currently preclude gene drive experiments in natural populations. Mathematical models can prove useful in elucidating the expected behavior of gene drives in response to a number of biological factors and can also reveal patterns of gene drive spread that are too complex to be intuitively predicted. The assumptions and details of a mathematical model influence the applicability of the results to natural populations, similar to the role that experimental conditions play for laboratory experiments. Part of the Gene Drive Modeling Conference Seminar Series, this presentation by Dr. Sumit Dhole will focus on how simple mathematical models can be used to study expected gene drive behavior, and how biological details can be added to simple models to address the effects of factors like migration and population-density dependence. A particular gene drive, called Engineered Underdominance, which has potential for spatially restricted population alteration will serve as a case study.

Simple and Complex Models: Their Roles in the Evaluation of Gene Drives

Dr. Alun Lloyd

Department of Mathematics, North Carolina State University

Mathematical models are a widely-used tool to assess the feasibility and effectiveness of gene drives and other related biocontrol approaches. As part of the Gene Drive Modeling Conference Seminar Series, this presentation by Dr. Alun Lloyd will cover modeling work that has been carried out for several novel strategies, illustrating the use of a number of different models as the projects move along the path from theoretical proposals, through lab-based studies, to field deployment. Of particular note is the role of both simple and more complicated mathematical models at various stages of this process. Dr. Lloyd will also discuss the benefits and drawbacks of different approaches, together with methods that can be used to quantify uncertainty in model predictions that result from uncertainty in model parameters.

Informing Risk Assessment with the Mosquito Gene Drive Explorer (MGDrivE)

Ms. Valeri Vasquez

Berkeley Institute for Data Science, University of California, Berkeley

May 20, 2019 | 1:00 pm – 2:00 pm

The advent of CRISPR/Cas9-based gene-editing and its demonstrated ability to streamline the development of gene drive systems has reignited interest in the application of this technology to disease-transmitting mosquitoes and insect agricultural pests. The versatility of the technology has also enabled a wide range of gene drive architectures to be realized, creating a need for their population-level and spatial dynamics to be explored using mathematical models. The Mosquito Gene Drive Explorer (MGDrivE) is a simulation framework designed to investigate the population dynamics of a variety of gene drive systems as they spread through spatially-explicit insect populations. While MGDrivE was primarily designed for application to the mosquito vectors of malaria and arboviruses such as dengue, Zika, and chikungunya, its modularity means that, with a few small changes, it could be applied to insect pests of agricultural significance, such as the medfly, spotted wing drosophila, or the Asian citrus psyllid vector of Citrus Huanglongbing. This online seminar will focus on the modules of the MGDrivE framework, including assumptions, uncertainties, and planned modifications for agricultural pests. The presenters will demonstrate the tool’s application in a few toy scenarios and discuss relevance to important risk assessment questions in the agricultural space.

Agenda

Day 1 - Tuesday, June 11, 2019

8:00 am

Opening Remarks - Purpose of the Workshop

Andrew Roberts, Agriculture & Food Systems Institute

Session 1: Introduction to Gene Drives

8:15 am

Mitigating the Risk of Unintended Spread of a Gene Drive

Kevin Oh, United States Department of Agriculture
Valentino Gantz, University of California San Diego

Genetic containment of a mouse gene drive using locally fixed alleles; modeling unintended gene drive spread.

8:45 am

Potential Applications of Gene Drives in Agriculture

Max Scott, North Carolina State University

Agriculture pests that could be targeted through gene drives; what are the limitations and constraints on agricultural applications?

Session 2: Regulatory Considerations

9:15 am

Coordinated Framework for the Regulation of Biotechnology

Elizabeth Milewski, United States Environmental Protection Agency

How gene drives fit into existing regulatory frameworks.

9:45 am

International Perspectives

Owain Edwards, Commonwealth Scientific and Industrial Research Organisation

Transboundary movement of genetically modified organisms; the Convention on Biodiversity (CBD) and gene drives.

10:15 am

Integrating Models into Risk Assessment

Andrew Kanarek, United States Environmental Protection Agency

How mathematical models are currently used for risk assessment.

10:45 am

Tea Break

Session 3: Modeling for Gene Drives

11:15 am

Evolution of Resistance Against CRISPR/Cas9 Gene Drive

Philipp Messer, Cornell University

Strategies that could facilitate the engineering of drivers with lower resistance potential.

11:45 am

Daisy-Chain Gene Drives for the Alteration of Local Populations

Rey Edison, Esvelt Group, Massachusetts Institute of Technology

Modeling of mechanisms that might be used to limit the geographic spread of gene drive organisms.

12:15 pm

Tethered Homing: Expanding the Power of Threshold Drives for Local Population Alteration

Sumit Dhole, North Carolina State University

The use of tethered homing to get around the limitations of threshold drives without compromising spatial restriction.

12:45 pm

Lunch Break

Session 4: Introduction of Case Studies for Discussion

2:00 pm

Informing Risk Assessment with the Mosquito Gene Drive Explorer (MGDrivE)

Valeri Vasquez & John Marshall, University of California, Berkeley

2:45 pm

Simple and Complex Models: Their Roles in the Evaluation of Gene Drives

Alun Lloyd, North Carolina State University

3:30 pm

Tea Break

4:00 pm

Discussion

All

4:45 pm

Review of Case Studies and Instructions for Breakout Groups

John Teem, Agriculture & Food Systems Institute

5:15 pm

Adjourn Day 1

Day 2 - June 12, 2019

8:00 am

Welcome and Review of Day 1

John Teem, Agriculture & Food Systems Institute

Breakout Sessions

8:15 am

Review of Instructions for Breakout Groups

John Teem, Agriculture & Food Systems Institute

8:30 am

Breakout Groups

10:30 am

Tea Break

Plenary Review

11:00 am

Discussion of Breakout Group Results

12:00 pm

Lunch Break

1:30 pm

Panel Discussion

All

2:30 pm

Lessons Learned and Future Prospects

Based on the prior two sessions, participants will be asked to identify areas of useful research investigation related to gene drive modeling and criteria for establishing gene drive models that could inform risk assessments

4:00 pm

Tea Break

4:30 pm

Recap and Final Discussion

Andrew Roberts
Agriculture & Food Systems Institute

5:30 pm

Adjourn

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