The other modification is a set of genetic elements known as a gene drive that should propel the malaria-resistance genes throughout a natural mosquito population.
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Malaria survives by using blood-feeding mosquitoes as hosts, since they’re suitable to pass the parasite into humans and animals every time they feed, quickly spreading the disease.
Professor David Conway, the United Kingdom expert from the London School of Hygiene & Tropical Medicine has said: “It’s not the finished product yet but it certainly looks promising”.
The UN World Health Organization estimates there will be 214 million cases of malaria worldwide in 2015 and 438,000 deaths, most in sub-Saharan Africa.
Researchers followed the Crispr method, a gene-editing technique used to insert DNA into the nucleus of a cell in order to replace mutated genes or add new ones.
At the University of California-Irvine, molecular biologist Anthony James is developing what he calls “sustainable technologies” – rather than killing mosquitoes, instead rendering them unable to infect people. He tested the new gene on the eggs of an Indian mosquito species Anopheles stephensi – that way, if the bugs somehow escaped, they’d find themselves on a foreign continent with an inhospitable climate and no one to mate.
Biologist George Dimopoulos of Johns Hopkins University, who had separately engineered mosquitos to resist the malarial parasite with different genes, said that the study marks a “very important advance in the field of mosquito biology”.
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James is a member of the National Academy of Sciences, which has convened a committee to review the ethical implication of gene editing and gene drive research. Next, they used a “gene drive” to copy the genes onto both chromosomes of offspring, per the Washington Post. The two teams came together after Dr Gantz and Dr Bier developed a gene drive for the Drosophila fruit fly, a standard laboratory organism, to help identify genetically mu tant insects. The idea comes from a few examples in nature where certain genes spread disproportionately, and scientists have longed for a way to control that process. Gantz packaged antimalaria genes with a Cas9 enzyme (which can cut DNA) and a guide RNA to create a genetic “cassette” that, when injected into a mosquito embryo, targeted a highly specific spot on the germ line DNA to insert the antimalaria antibody genes. To measure, they tacked on a fluorescence gene that made mosquitoes’ eyes look red if they harbored the new gene. Among the findings to be addressed was that the transgenic male mosquitoes passed their new trait to the next generation more efficiently than transgenic females did. One worry is the possibility of altered organisms escaping the laboratory before scientists know how to use them. They’re only flying around a lab for now, but researchers hope the insects will eventually help stop the spread of the disease among humans. “Somebody sitting in the US making up a list of rules has to appreciate that these countries have their own concerns”, James said.
