Creating transgenic animals: routes of DNA delivery Which of the following are recognized methods of transfection or genetic material transfer used when making transgenic animals?

Introduction / Context:
Transgenic animal production employs several routes to introduce genetic material. Understanding these options helps in selecting appropriate technology for trait insertion, gene knock-in, or complex genome edits.

Given Data / Assumptions:

• We consider laboratory-validated methods, not just theoretical possibilities.
• Goal is heritable modification of the germ line or creation of cloned transgenic animals.

Concept / Approach:
Common routes include (1) nuclear transfer (moving an entire diploid nucleus into an enucleated oocyte), (2) chromosome transfer (microcell-mediated chromosome transfer), and (3) DNA delivery methods (pronuclear microinjection, lentiviral/retroviral vectors, transposons, CRISPR/Cas9 components).

Step-by-Step Solution:

Verification / Alternative check:
Published protocols document successful animals generated via pronuclear microinjection, SCNT, viral transduction of embryos, and chromosome transfer.

Why Other Options Are Wrong:

• Each single-method option is incomplete.
• “None; only selective breeding” ignores modern genetic engineering.

Common Pitfalls:
Assuming one method suits all species or edits; payload size, mosaicism risk, and regulatory context dictate method choice.

Final Answer:
All of the above