Microinjection into a fish embryo against a cosmic backdrop, symbolizing genetic manipulation and evolutionary potential.

Unlocking Evolution's Secrets: How Gene Editing is Rewriting the Rules of Natural Selection

Theo Raines in Science & Nature August 2025 • 4 min read.

"Delve into the groundbreaking techniques of microinjection and genome editing in threespine sticklebacks, revealing how scientists are manipulating genes to understand the basis of biodiversity and adaptation."

The world of evolutionary biology is constantly evolving, driven by new technologies and innovative approaches. At the forefront of this revolution is the threespine stickleback fish, a seemingly ordinary creature that has become an extraordinary model for understanding the genetic underpinnings of biodiversity. These fish have adapted to a myriad of environments, displaying a remarkable range of physical and behavioral traits. This adaptability, combined with cutting-edge genetic tools, makes them invaluable for scientists seeking to unravel the mysteries of evolution.

In a fascinating study published in the Journal of Visualized Experiments, researchers detailed a powerful technique for manipulating the genes of threespine sticklebacks: microinjection. This method allows scientists to introduce foreign DNA or gene-editing tools into the fish embryos, enabling them to study the function of specific genes and regulatory elements. By precisely altering the genetic code, researchers can observe how these changes impact the fish's development and behavior, providing unprecedented insights into the mechanisms of evolution.

This article explores the intricacies of microinjection and genome editing in threespine sticklebacks, highlighting its potential to revolutionize our understanding of evolutionary processes. This work not only showcases the power of genetic manipulation but also highlights how simple organisms can provide profound insights into the complexity of life.

Microinjection: A Gateway to Genetic Manipulation

Microinjection into a fish embryo against a cosmic backdrop, symbolizing genetic manipulation and evolutionary potential.

Microinjection is a technique used to introduce substances into a cell using a fine needle. In the context of threespine sticklebacks, this involves injecting DNA or gene-editing reagents into fertilized, one-cell embryos. This process is made challenging by the stickleback's tough outer membrane (chorion) and the small size of the blastomere, the cell that will eventually develop into the fish. The protocol involves carefully preparing the injection needles, fertilizing the eggs, and precisely delivering the genetic material into the embryo.

The success of microinjection hinges on several key factors. First, the injection needles must be sharp enough to penetrate the chorion without damaging the embryo. Second, the timing of the injection is critical; it must be performed at the one-cell stage to ensure that the genetic material is incorporated into all the cells of the developing fish. Finally, the amount of injected material must be carefully controlled to avoid toxicity or developmental abnormalities.

Proper needle preparation is key to puncturing the tough chorion.
Timing the injection at the one-cell stage is crucial for genetic integration.
Controlled injection volume prevents toxicity and ensures normal development.
Maintaining optimal environmental conditions supports embryo viability.

Several methods for studying gene regulation, assessing gene function, and inducing targeted mutations are outlined in the original paper. Transgenic reporter plasmids and Bacterial Artificial Chromosomes (BACs), integrated using the Tol2 transposase system, allow researchers to study gene regulation. Functions of candidate genes and cis-regulatory elements are assessed using TALEN and CRISPR/Cas9 genome editing reagents. All these methods involve the microinjection of nucleic acids.

The Future of Evolutionary Research

The work on threespine sticklebacks is just the beginning. As genome editing technologies continue to advance, scientists will gain even greater control over the genetic makeup of organisms, paving the way for groundbreaking discoveries in evolutionary biology, medicine, and beyond. These methods offer a powerful approach to dissecting the genetic basis of complex traits and understanding how evolution shapes the diversity of life on Earth.

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This article is based on research published under:

DOI-LINK: 10.3791/54055, Alternate LINK

Title: Microinjection For Transgenesis And Genome Editing In Threespine Sticklebacks

Subject: General Immunology and Microbiology

Journal: Journal of Visualized Experiments

Publisher: MyJove Corporation

Authors: Priscilla A. Erickson, Nicholas A. Ellis, Craig T. Miller

Published: 2016-05-13

Everything You Need To Know

What does microinjection entail when performed on threespine sticklebacks, and what challenges are associated with it?

Microinjection in threespine sticklebacks involves injecting DNA or gene-editing reagents into fertilized, one-cell embryos. This is challenging due to the tough outer membrane called the chorion, and the small size of the blastomere. Proper needle preparation, timing the injection at the one-cell stage, and controlling the injection volume are crucial for success. Failure to address these issues can lead to embryo damage, failure of genetic integration, or developmental abnormalities. The process allows scientists to directly manipulate the genetic material of the fish to study the impact on its development and behavior.

What tools do researchers use, alongside microinjection, to study gene regulation and assess gene function in threespine sticklebacks?

The study uses transgenic reporter plasmids and Bacterial Artificial Chromosomes (BACs), integrated using the Tol2 transposase system, to allow researchers to study gene regulation. Additionally, the functions of candidate genes and cis-regulatory elements are assessed using TALEN and CRISPR/Cas9 genome editing reagents, all involving microinjection of nucleic acids. This allows for precise manipulation and observation of specific genetic components.

What are the main implications of using microinjection of gene editing tools in threespine sticklebacks?

Microinjection of gene editing tools in threespine sticklebacks offers a direct method for studying gene function and observing the impacts on development and behavior. By altering the genetic code, scientists can gain insights into how specific genes contribute to the evolution of traits and adaptations, which would be much harder to study without direct manipulation.

How is the CRISPR/Cas9 system utilized in the context of gene editing in threespine sticklebacks, and what does it allow researchers to investigate?

Gene editing with the CRISPR/Cas9 system allows for targeted mutations in the genome of threespine sticklebacks. This is achieved by injecting CRISPR/Cas9 genome editing reagents to assess the functions of candidate genes and cis-regulatory elements. By observing the resulting changes in the fish, researchers can determine the role of these specific genes in the fish's traits and evolutionary adaptations. It's a powerful tool to understand the genetic basis of complex traits.

How will future advancements in genome editing technologies influence evolutionary research involving threespine sticklebacks, and what broader implications can be anticipated?

The ongoing advancements in genome editing technologies for threespine sticklebacks mean scientists are gaining greater control over the genetic makeup of organisms. This paves the way for discoveries not only in evolutionary biology, but also in medicine and potentially other fields. These methods will offer approaches to dissect the genetic basis of complex traits and understanding how evolution shapes the diversity of life on Earth. Without these methods, our understanding of the interplay between genes and evolution would be much more limited.