What technique involves inserting DNA directly into a fertilized egg?

The technique that involves inserting DNA directly into a fertilized egg is known as pronuclear injection. This method is used primarily in the field of transgenic animal production, where foreign DNA is integrated into the genome of an organism. By injecting the DNA into one of the pronuclei of a fertilized egg (which contains the maternal or paternal genetic material), the introduced DNA can be incorporated into the developing embryo's genome.

As the embryo begins to divide, the newly introduced genetic material can be expressed in all cells of the resulting organism if it integrates properly into the host genome. This allows for the creation of transgenic animals that express specific traits or proteins of interest.

In contrast, other options presented serve different purposes. Gene therapy typically involves delivering genetic material to cells in an established organism to treat or prevent disease, rather than injecting into an embryo at the fertilized egg stage. RNA interference is a biological process that regulates the activity of genes post-transcriptionally and does not involve DNA insertion. Genomic sequencing refers to determining the complete DNA sequence of an organism's genome, rather than a technique for modifying genetic information directly within fertilized eggs.