8.11: Gene Modification Approaches

Inserts functional genes to add or improve traits, including disease-resistant pigs, cattle with reduced BSE susceptibility, and AquAdvantage® salmon that grow nearly twice as fast.

Turns off defective or harmful genes using RNA interference (RNAi). Small interfering RNA (siRNA) and microRNA (miRNA) target and degrade specific mRNA molecules, reducing gene expression. RNAi therapeutics are being explored for Huntington's disease, cancer, and viral infections.

CRISPR-Cas9 allows precise, targeted DNA modification. A single-guide RNA (sgRNA) directs Cas enzymes to specific genomic sites where they can knock out genes by creating double-stranded breaks, replace mutated sequences with correct copies, or insert new DNA during repair. While powerful, CRISPR requires careful validation to avoid unintended edits.

Image credit: To CRISPR article for more in depth information(opens in new window) [Perisse I.V., Fan Z., Singina, G.N., White, K.L. and Polejaeva, I.A. (2021) Improvements in gene editing technology boost its applications in livestock. Figure 2. Frontier. Genetics. 11:614688. doi: 10.3389]

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