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CRISPR Gene Editing: We Could Eliminate Malaria But Should We?

CRISPR Gene Editing: We Could Eliminate Malaria But Should We?

The biotech field of genetic engineering has been developing since the 1970s. After we learned that genes were made of DNA biotech scientists started trying to manipulate them. Much of modern agriculture has been influenced by the genetic engineering of crops. We’ve spliced strains, plant species and made crops more resistant to diseases and parasites as well as increasing yields and sometimes heightening nutritional value. But it took time and money.

In 2013 it was announced that the CRISPR gene-editing tool had been discovered. The molecular tool allows scientists to snip DNA proteins, removing or adding sections. It’s made genetic engineering much cheaper, more accurate and far easier. And it’s handed us a power over nature that now poses serious practical and ethical questions.

CRISPR biotechnology is facilitating an acceleration in breakthroughs around crop engineering as well as offering hope of new, effective cancer treatments and antibiotics that will hopefully be able to keep up with mutating bacteria becoming resistant. However, it’s the combination of CRISPR with something called a ‘gene drive’ that is perhaps the biotechnology’s greatest power. A gene drive is a genetic engineering tool that is used to spread CRISPR edited genes through an entire biological population.

Work is already being done on a CRISPR-enabled gene drive that would have the potential to wipe out localised populations of malaria-carrying mosquitos. Malaria is one of the highest causes of fatality in large parts of the developing world and accounts for half a million human deaths every year. Another potential application is poisonous cane toads in Australia. They are an invasive species not native to the continent and having grown into a huge population, their toxins have a devastating impact on indigenous flora and fauna in regions where numbers are highest.

Researchers at London’s Imperial College have created a CRISPR gene drive that means female mosquitoes, which are those that are able to bite humans and drink their blood, are born infertile and also lack the kind of proboscis (the tubular mouth made of six needle-like parts) able to pierce human skin and suck blood out.

Cane toads were introduced into Australia by a government-owned sugar cane enterprise as a way to control parasitic beetle infestations destroying the crop. However, they thrived in Australia and the population multiplied out of control. Their poisonous skins proved lethal to would-be predators. The result has been a heavy impact on native species of flora and fauna. Now a CRISPR gene drive that would stop the toads from producing their toxins could be introduced into the Australian population. The toads would become vulnerable to predators with the expected result populations being either severely reduced or completely wiped out.

Genetic alterations that self-propagate by being passed down generations are, however, potentially very risky. It’s almost impossible for scientists to accurately predict the exact long term repercussions of introducing genetically altered species. As a result, the scientific community is in favour of limiting the kind of CRISPR gene drives now possible to a small set of parasites, such as malaria-carrying mosquito strains, that cause ‘widespread human suffering’.

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