In: Biology
A CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. This is a bacterial defence system that forms the basis for CRISPR-Cas9 genome editing technology. Its a way of finding a specific bit of DNA inside a cell and editing it.
Limitations:
The molecular mechanism exploited to insert DNA fragments is mediated by DNA repair machinery activated by the double strand break introduced by Cas9. Since the scope of the DNA repair system is not to integrate DNA fragments in the genome, targeted alleles often carry additional modifications, such as:
When performing the CRISPR/Cas9 procedure directly on embryos, on the other hand, it is impossible to select for the desired event, greatly limiting the possibility to identify the desired allele.
The mosaicism observed in founder mice generated using this approach make the identification of unwanted genomic modifications at the target site very challenging.
There is also more severe problems such as: