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The gene genies

  Newsletter Article

Genetic engineering divides opinions: For some, it holds the promise of beating world hunger and fighting diseases. For others, it is an objectionable, ethically reprehensible intervention in nature with unforeseeable and possibly uncontrollable consequences. The fact is that genetic engineering is already used to breed especially resistant crops – and to fight dangerous diseases that claim more than one hundred thousand human lives every year.

One of these is malaria, one of the world's deadliest infectious diseases: In 2016, the WHO recorded more than 216 million malaria cases; that claim hundreds of thousands of human lives every year. According to figures published by the WHO, the Zika virus is also spreading rapidly and is suspected of having impaired the brain development of more than 4,000 babies of infected pregnant women. In both cases, a method is set to be used that has already proved successful in the past: In 1997, scientists on the island of Zanzibar succeeded in wiping out the tsetse fly, a transmitter of sleeping sickness, by breeding flies on a large scale, sterilizing the males with radiation, and releasing them. The result: They mated with wild tsetse flies, but produced no offspring. After 18 months, the population collapsed.

Unlike flies, however, disease-carrying mosquitos are not fit enough to compete with their wild counterparts after receiving radiation treatment. For this reason, a different method is needed to fight the Zika virus and malaria - and this is where CRISPR comes into play. The molecular complex makes it possible to change the genetic makeup of all living organisms more quickly, easily, and efficiently than ever before. Just like using a pair of scissors, researchers can use the method to cut out certain sections of a gene, make corrections, or replace them with other sections.

In the case of the mosquitos that transmit the Zika virus, scientists want to alter their genes so that they or future generations are rendered infertile. Alternatively, the scientists could make the insects resistant to the pathogen that is dangerous to humans and prevent infections in this way. Another method involves the mosquitos ridding themselves of the pathogen by developing antibodies to counter it. Until now, this genetics-based method, which results in the altered gene from the second generation onward only being passed onto one in four mosquitos, has proved to be inefficient. Thanks to CRISPR, it is now possible to guarantee that every mosquito living in the wild is given the corresponding genetic code.

There are high hopes within the research community that the new possibilities afforded by CRISPR could also cure diseases such as cancer and AIDS. At the same time, however, the research requires strict rules so that the scientists don't act like "careless cowboys," says Kevin Esvelt from the Wyss Institute in Cambridge. Strict rules, such as authorization from a commission of experts and special laboratory designs that prevent the insects from escaping, would be a step in the right direction.

In the meantime, CRISPR is not just creating undreamed-of possibilities when it comes to fighting diseases. The method can also be used for species conservation - at least in theory. For example, the artist Alexandra Daisy Ginsberg imagines self-inflating anti-pathogenic membrane pumps that cure sick oak trees from infections that would otherwise kill them. Another idea is the disperser - a creature that gathers, disperses, and reliably buries the seed from plants. Or a self-renewing biofilm that covers the surface of plant and captures and stores harmful substances from the air.

But enough of the pipe dreams for now and back to the possibilities already afforded by CRISPR: The method makes it possible to use bacteria for storing data. A team of researchers from the USA has converted a photo of a hand and a short video of a horse into binary code and uploaded it to the genome of E. coli bacteria. In order to transform the 24,000 zeroes and ones contained in these two files into a storable form, the researchers converted them into a series of the four nucleobases adenine, guanine, cytosine, and thymine from which human DNA is constructed. The code was loaded into the individual bacteria of a population with the help of viruses.

The method has potential: Researchers have calculated that 215,000 terabytes of data could be permanently stored using just one gram of DNA material. Furthermore, the genetic material is also more durable than conventional storage media: In 2013, scientists were able to isolate the genetic material of a horse preserved in permafrost - after 700,000 years!
Here at Rutronik24, this is good news: Instead of preserving all of our newsletters for a mere couple of years or decades, we could more or less keep them for eternity. That's good to know!