In April, a team of Chinese scientists announced they'd used CRISPR
to edit genes in human embryos, and in September a group of UK scientists asked for permission to do the same.
The paper not only reveals the function of a previously uncharacterized CRISPR
system, but also shows that Cpf1 can be harnessed for human genome editing and has remarkable and powerful features.
On closer inspection, it turns out to be anything but simple to decide how far we should go in researching and applying CRISPR
to the human germline.
However, this particular A14-B21 CRISPR
profile is displayed by 37 Salmonella Enteritidis genomes deposited in the GenBank public database and originating in poultry or humans from North America (8,11,12) (online Technical Appendix 3, http://wwwnc.
is a system of molecules that allows scientists to alter DNA with exquisite precision.
enzymes were first discovered in bacteria in the 1980s as an immune defence used by bacteria against invading viruses.
Sequences obtained were compared with sequences reported (21-23) and those in the CRISPR
The stolen DNA pieces are stored in specific locations in the bacterial genome called CRISPR
(clustered regularly interspaced short palindromic repeats) loci.
Chinese researchers utilized the character of CRISPR
/Cas's specific recognition of virus and exogenous DNA found lately in bacteria, and then transplanted the cutting system of CRISPR
into plants and built DNA virus defense system in plants.
Cas9, an enzyme in the CRISPR
system that makes cuts in DNA and allows new genetic sequences to be inserted, has generally been introduced into cells using viruses or circular bits of DNA called plasmids.
Those researchers say that while CRISPR
technology is still too primitive for safe use in patients, further research is needed to improve it.
Further studies underlined the limitations of CRISPR
-based typing: the 3 described CRISPR
loci are not present simultaneously in all isolates; and most strains have unique spacers at the leader part of the array, which indicates their independent evolution after they diverged from a common ancestor (9).