Question

How does microinjection of DNA into cells work, and why is plasmid recombination still used despite microinjection's direct gene insertion?

A) Microinjection involves the direct introduction of DNA into cells; however, plasmid recombination is preferred due to its specificity in gene editing and precise insertion into bacteria.
B) Microinjection lacks the precision for specific gene insertion into the nucleus, necessitating plasmid recombination for controlled gene transfer.
C) Plasmid recombination and microinjection each serve distinct purposes: plasmids are used in bacteria, while microinjection is utilized in eukaryotic cells.
D) While microinjection directly delivers genes into cells, plasmid recombination offers the necessary components for targeted gene expression and replication, especially in bacteria.

Answer 1

Microinjection is used to directly introduce DNA into eukaryotic cells, while plasmid recombination is preferred for bacterial cells due to its ability to specifically insert and replicate genes. Plasmid recombination is essential for controlled gene transfer and is supported by selection techniques that allow for the identification of successfully modified bacteria.

Step-by-step explanation:

Microinjection and Plasmid Recombination

Microinjection is a technique for introducing DNA directly into eukaryotic cells. This procedure involves using a glass micropipette to inject DNA fragments into the cytoplasm, and in some cases, directly into the nucleus of the cell. The microinjection needle can penetrate both the cell membrane and the nuclear envelope, ensuring that the recombinant DNA reaches its target location within the cell. However, eukaryotic cells are less amenable to maintaining plasmids as they do not naturally take up or replicate foreign DNA without specific integration.

Despite the directness of microinjection, plasmid recombination is still widely used, particularly for introducing recombinant DNA into bacterial cells. Plasmid recombination offers specific advantages, including the ability to replicate independently within bacterial cells, and it can be used to insert genes with a high degree of specificity. This is essential for ensuring controlled gene transfer. Additionally, selection techniques following transformation, such as those involving lacZ and antibiotic resistance genes, allow for the identification and propagation of successfully modified bacteria. In molecular cloning using transformation, engineered plasmids are introduced into bacteria which can uptake free DNA from their surroundings, offering an efficient method for genetic engineering.

Therefore, while microinjection offers an efficient way to insert DNA into eukaryotic cells, plasmid recombination remains a staple in bacterial genetic engineering due to its targeted insertion and replication capabilities.