申論題內容
1. The ability to engineer biological systems and organisms holds enormous potential for applications
across basic science, medicine and biotechnology. Programmable sequence-specific endonucleases that
facilitate precise editing of endogenous genomic loci are now enabling systematic interrogation of
genetic elements and causal genetic variations in a broad range of species, including those that have
not previously been genetically tractable. A number of genome editing technologies have emerged in
recent years, including zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases
(TALENs) and the RNA-guided CRISPR-Cas nuclease system. The first two technologies use a
strategy of tethering endonuclease catalytic domains to modular DNA-binding proteins for inducing
targeted DNA double-stranded breaks (DSBs) at specific genomic loci. By contrast, Cas9 is a nuclease
guided by small RNAs through Watson-Crick base pairing with target DN'A, representing a system that
is markedly casier to design, highly specific, eficient and well-suited for high-throughput and
multiplexed gene editing for a variety of cell types and organisms (8 分).