Gene Editing Technology

Question 1

CRISPR-Cas9

Answer 1

a gene editing technique that can remove, add, or change specific DNA sequences in the genome of living cells

Question 2

CRISPR

Answer 2

clustered regularly interspersed palindromic repeats

Question 3

Cas9

Answer 3

a nuclease (obtained from Streptococcus pyogenes) that creates double-strand breaks under two conditions:
-only cuts DNA near a protospacer adjacent motif (PAM) - 5’-NGG-3’
-requires a single guide RNA (sgRNA) for specificity

Question 4

Diverse Applications of C R I S P R-Cas

Answer 4

Creation of tomatoes that ripen quickly.
“Bringing back” the woolly mammoth.
Fight off diseases in livestock.
Modify food crops for additional nutritional traits, pest, and drought resistance.
Most anticipated applications:
-Gene therapy
-Clinical trials already underway for cancer

Question 5

C R I S P R-Cas does have limitations

Answer 5

Cas9 can cut at off-target sites in genome.
s g R N A may have more than one perfect match.
s g R N A may direct Cas9 to sequences with one or few mismatches.
Solutions in progress:
-Modify Cas9 to improve specificity.
-Improve s g R N A design via algorithms.
-Find alternative enzymes from bacteria or archaea.