CRISPR technology is a simple yet powerful tool for editing genomes. It allows researchers to easily alter DNA sequences and modify gene function. The protein Cas9 (or "CRISPR-associated") is an enzyme that acts like a pair of molecular scissors, capable of cutting strands of DNA.
CRISPR is a family of DNA sequences in bacteria and archaea. The sequences contain snippets of DNA from viruses that have attacked the prokaryote. These snippets are used by the prokaryote to detect and destroy DNA from similar viruses during subsequent attacks. These sequences play a key role in a prokaryotic defense system, and form the basis of a technology known as CRISPR/Cas9 that effectively and specifically changes genes within organisms.
CRISPR is an abbreviation of Clustered Regularly Interspaced Short Palindromic Repeats. The name was minted at a time when the origin and use of the interspacing subsequences were not known. At that time the CRISPRs were described as segments of prokaryotic DNA containing short, repetitive base sequences. In a palindromic repeat, the sequence of nucleotides is the same in both directions. Each repetition is followed by short segments of spacer DNA from previous exposures to foreign DNA (e.g., a virus or plasmid). Small clusters of cas (CRISPR-associated system) genes are located next to CRISPR sequences.
Genetic Modification, Genome Editing, and CRISPR
Since the late 2000s, scientists began to develop techniques known as “genome (or gene) editing.” Genome editing allows scientists to make changes to a specific “target” site in the genome. One of the techniques that have generated the most excitement, due to its efficiency and ease of use, is called “CRISPR.” CRISPR stands for “clustered regularly interspaced short palindromic repeats.” The basis of CRISPR technology is a system that bacteria evolved to protect themselves against viruses. Scientists have now taken components of the CRISPR system and fashioned it into a tool for genome editing.
Gene editing has significant potential to benefit human health. At the same time, it raises profound questions that require public deliberation — what if we make alterations we regret? What if seemingly safe genetic changes prove to have unintended consequences? What are the standards for safety as the medical community seeks to explore these tools in an effort to diminish suffering? Additionally, if as a society we agree that the use of genome editing is acceptable, how do we ensure that all individuals are aware of the potentials of these technologies, and that everyone who wants to access such technologies can afford them? Researchers, bioethicists and policymakers, including a number of the scientists who pioneered CRISPR, have called for caution and the need for public consultation and dialogue that also involves faith leaders, environmental activists, and advocates for patients and for people with disabilities. As society seeks a balance between the desire to realize the benefits of gene editing and a variety of other concerns, pgEd hopes to play a part in facilitating broad conversations that engage all communities and ensure that diverse values and voices are heard.  Personal Genetics Education Project.