What common method is used to insert DNA into fertilized eggs besides pronuclear injection?

Retroviral insertion is a common method used to introduce DNA into fertilized eggs, particularly in the creation of genetically modified organisms. This technique involves using a retrovirus as a vector, which has the natural ability to integrate its RNA into the host's DNA. In the context of inserting DNA into fertilized eggs, the retrovirus can carry the desired genetic material and facilitate its incorporation into the genome of the developing embryo.

This method is widely used because retroviruses can effectively infect dividing cells and integrate genes stably into the host genome, leading to the expression of the inserted gene in the resulting organism. It provides a relatively straightforward way to manipulate genetic material as part of research or therapeutic interventions.

Other options, while related to genetic manipulation, do not serve as common methods for inserting DNA into fertilized eggs in the same way. For instance, CRISPR technology is primarily known for its precise editing capabilities and is often used for gene editing rather than direct insertion into fertilized eggs. Gene splicing refers to a broader range of techniques for manipulating genes and is not specifically focused on the process of insertion into embryos. Viral replication refers to the process by which viruses reproduce within host cells and does not pertain specifically to the insertion of DNA into fertilized eggs