CRISPR is an acronym for “Clustered regularly-interspaced short palindromic repeats.” It is a relatively new genome editing tool that functions like molecular scissors. The method allows scientists to modify an organism’s DNA.
CRISPR is based on the functionality of a bacterium’s immune system. With this defensive mechanism, parts of viruses that infect bacteria are retained within the bacterial genome. This allows the bacterium to later recognize and defend itself against viral infections in the future. CRISPRs are found in approximately 40 percent of sequenced bacteria genomes.
The editing technology was advanced by Dr. Jennifer Doudna. Dr. Doudna discovered the use of an enzymatic protein called Cas9 which could advance the editing approach. Using a Cas9 protein and appropriate guide, genetic material can be easily delivered into a cell in any desired location. Controversially, this is also possible with human cells.
CRISPR-Cas9 has enabled scientists, in animal tests, to switch potentially faulty genes with other healthy ones. Based on this, a company called Editas Medicine is seeking to use the technology for human testing. This is to help with research into genetic diseases like Huntington’s Disease and Cystic Fibrosis, with the aim to identify if two parents are likely to give birth to a child with such a disease and then attempt to edit out the problem gene in human embryos. Considerable regulatory hurdles stand in the way of this happening, although discussions are taking place. The U.S. National Institutes of Health (NIH) has previously indicated it will not support any research on human embryos.
The process of gene editing an embryo is feasible. Earlier in 2014, the first primates were born whose genomes were edited using the novel CRISPR technology. In addition, a university in China has apparently carried out some tests on human embryos. This took place in 2015 at the Sun Yat-sen University in Guangzhou. The aim was to investigate if germline technologies could be used to replace faulty genes in early stage development human embryos. However, the results were not regarded as successful when reviewed by independent scientists.
Not everyone is happy with CRISPR technology for such applications, for ethical reasons. A leading campaign body against such research is The Center for Genetics and Society (CGS). As well as the human studies, other scientists worry about the application with food.
Recently, a gene-edited mushroom caused controversy by not needing any regulation according to the United States Department of Agriculture (USDA). The mushroom had undergone gene editing using CRISPR/Cas9.
According to the USDA, the mushroom did not require regulation like other genetically modified crops. The mushroom was developed by Dr. Yinong Yang, who is employed at Penn State University. Dr. Yang used CRISPR/Cas9 technology to cut away a small part of one gene from the mushroom Agaricus bisporus. The reason for doing so was to reduce browning when the mushroom is sliced. The reason for avoiding regulation is because the gene editing left no foreign DNA behind.
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