CRISPR, a genome-editing technology that has been progressing rapidly in the last three years, has just been named Science’s Breakthrough of the Year. CRISPR is a futuristic technique that can be used to edit and manipulate the DNA of any organism—crops, livestock, and even humans. It can allow scientists to control gene expression and selectively turn genes on or off.

In 2015, two significant advances contributed to CRISPR’s status as this year’s Breakthrough technique. The first was the engineering of a “gene drive” in insects that could benefit human health by eliminating pests and the diseases they carry. The second was gene editing performed in human embryos, a process that sounds like something out of a science fiction novel and raises a host of legal and ethical questions about the manipulation of human DNA to create customized offspring.

CRISPR is not only remarkable for its ability to manipulate the DNA of a targeted organism, it is also remarkable because it is an extremely inexpensive and relatively easy technique to use. In terms of the resources it requires, it could be implemented in almost any microbiology lab worldwide.

CRISPR is an acronym that stands for “clustered regularly interspaced short palindromic repeats.” These repeats are created by bacteria from viruses during infections and serve as templates for a system that cuts the viral DNA. By modifying the system, it’s possible to get it to cut an arbitrary DNA sequence, allowing the targeting of specific genes.

Using it this way requires a few basic components. The first is a way of getting DNA into the cells of the target organism—use of a virus is typically the most convenient way. That DNA must encode some “guide RNA” that targets a specific DNA sequence. That sequence then codes for some targeted trait—for example, the guide RNA could help scientists target a gene linked to a specific disease.

An additional component is the DNA-cutting enzyme, and the one most commonly used is called Cas9. The gene that encodes Cas9 can be inserted into the same DNA that encodes the guide RNA templates. The guide RNA directs the Cas9 nuclease to the targeted DNA, which is then cut. When this cut is repaired, it can either result in a deletion of some DNA or a repair using different DNA supplied by the researchers. Cutting out the target DNA can effectively shut off the target gene, while targeted changes to a sequence can be used to turn on a target gene by manipulating the DNA that controls its activity.

While the technology is progressing rapidly, there are some ethical, ecological, and legal issues to sort through. For example, one exciting potential application of CRISPR is pest control. In many parts of the world, mosquitoes are dangerous and highly prevalent, and they transmit deadly diseases like malaria. While this may have hugely beneficial effects for human populations afflicted by mosquito-borne illnesses, a sharp decline in mosquito population density could have unforeseen ecological consequences, just as manipulating the population density of any animal or insect could have unforeseen consequences.

Many of the other things CRISPR could allow us to create—faster growing and more resilient livestock, peanuts that are hypoallergenic, and more—may have unforeseen consequences as well.

Finally, the most contentious use of CRISPR is its application to humans. CRISPR could provide a potential solution for many diseases that are genetically inherited, but researchers would need to consider the ethical implications of genetically altering patients. They would also need to consider the ethical implications of failing to use genetic modification if it has the potential to save a life.

Lawmakers might need to get involved, as there could be legal implications of gene editing. Use of this technology in human populations will likely need to be heavily regulated, though the implementation of strict regulation in itself raises the question of equitable access to potentially lifesaving CRISPR technology. Finally, the potential side-effects of CRISPR technology in humans are still unknown.

Regardless of how the ethical and legal implications are handled, CRISPR will inevitably have far-reaching effects. With further development, it should allow scientists to implement almost any imaginable genetic manipulation. As our understanding of the genome continues to progress, our ability to fine-tune our own gene expression will become more robust.

Some day, we may be looking at a world where genetic manipulation is as widespread and common place as it was in the dystopian movie GATTACA—let’s just hope that the real-life consequences aren’t as severe as the fictional ones.