Scientists at the University of California Davis have genetically engineered
rice to have high levels of beta-carotene using CRISPR technology.
"We used CRISPR to precisely target those genes onto genomic safe harbors,
or chromosomal regions that we know won't cause any adverse effects on the
host organism," said first author Oliver Dong, a postdoctoral scholar in the
UC Davis Department of Plant Pathology and Genome Center.
The researchers precisely inserted a very large fragment of DNA that does
not contain marker genes which are used in conventional genetic engineering.
Marker genes are retained over generations, which often triggers public
concern and stringent regulations of the transgenic products before their
introduction to the marketplace. According to Dong, scientists have done
targeted insertions before and without marker genes, but they haven't been
able to do it with such big fragments of DNA.
This opens up the possibility that genes controlling multiple desirable
traits, such as having high levels of beta-carotene as well as being
disease-resistant or drought-tolerant, can be clustered at a single position
within the genome.