Millions of genetically modified (GM) mosquitoes have been released in the Brazilian city of Piracicaba. These are mutant males that transmit to local females a gene that causes insect larvae to die before reaching puberty. This measure is intended to drastically reduce the population of mosquitoes that transmit dengue fever dangerous to humans. The new experiment is reported by New Scientist with reference to the PLOS Neglected Tropical Diseases magazine.
The GM mosquito was developed by the British biotechnology company Oxitec. In Brazil, she received carte blanche to experiment in any area. Oxitec is also awaiting approval from the US Food and Drug Administration (FDA) for insect testing in Key Haven, Florida.
Since April 2015, around six million GM insects have been released into the Piracicaba neighborhoods, where the highest concentration of Aedes aegypti mosquitoes (a vector of dengue fever) occurs.
They not only contribute to the early death of their offspring, but also make the larvae glow red in ultraviolet light - which gives scientists a tool to determine the effectiveness of this method. Biologists have placed pots of water in Piracicaba where Aedes aegypti females lay their eggs. The ratio of red to normal larvae indicated that 50 percent of the offspring were conceived from GM mosquitoes.
In a test in another Brazilian city (Juazeiro), Oxitec insects reduced the local population by 95 percent in six months, being almost twice as effective as the most powerful insecticides.
However, scientists do not know how much the reduction in the number of vectors affects the incidence. “In theory, the fewer mosquitoes, the fewer people become infected, but in reality everything needs to be checked. Many insects can only produce a few new cases of the disease and vice versa,”says Margareth Capurro of the University of São Paulo, head of the Joiseiro trial.
Other researchers also warn that the effect of the new technology may be short-lived: mosquitoes from other areas will fly in, and the healthy part of the population will soon return to its previous size. Only careful timing and timing of release of GM mosquitoes will fundamentally reduce the risk of contracting dengue fever.
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Oxitec is now awaiting the early start of testing in Florida. The FDA has already prepared its expert report and is expected to be published any day. However, residents of the state have been protesting against GM mosquitoes for several years. In Brazil, dengue fever affects up to a million people a year, while in the United States, GM insects are only designed to prevent the emergence of a dangerous disease, probably the fear of a hypothetical threat turned out to be weaker than the bias against mutant animals.
Dengue fever is a viral disease transmitted by female A. aegypti mosquitoes and occurs in Asia, Africa, Oceania and the Caribbean. The disease is characterized by fever, intoxication, bone and muscle pain, and can be fatal. Dengue fever affects about 100 million people a year.
Genetically modified pigs - twice as much meat
Scientists from South Korea and China have created a new breed of pig that has twice the muscle mass of their regular counterparts. The developers hope it will be the first GM organism approved for use in animal husbandry. It differs from experimental analogs in that it uses simple gene editing, rather than mixing genetic materials from different organisms.
Pigs with hypertrophied muscles may be the first approved GM organism
One of the authors of the development, molecular biologist Jin-Soo Kim from Seoul National University, notes that gene editing works the same as selection selection, but much faster. Animals with hypertrophied muscles are already being used in animal husbandry, for example, breeding Belgian blue and white cows. With gene editing, breeds like these can be produced without decades of selection.
So far, no transgenic animal strain has been approved for human consumption. For example, the fast-growing GM salmon has been awaiting a positive review from the US Food and Drug Administration for 20 years.
The new pig strain has a mutation in the myostatin gene (MSTN). Usually MSTN inhibits the growth of muscle cells and prevents the formation of excess muscle. But in some cases, in cattle, dogs and humans, the MSTN is disrupted and muscle cells proliferate, creating an abnormal number of muscle fibers.
Scientists have performed a similar directed mutation in pigs, resulting in animals with developed muscles. This is beneficial from an economic and environmental point of view, as it allows you to get twice as much meat from one animal.
To create the mutation, one of the most promising gene editing techniques was used - the TALEN technology, which uses an enzyme to cut DNA and a protein to edit genes. The scientists removed both copies of the MSTN gene from pig embryonic cells and created 32 cloned GM piglets.
The resulting animals have hypertrophied muscles, but do not contain DNA from foreign organisms, which increases the chances of regulatory approval. When no new elements are added to DNA, many regulators, in particular in the United States and Germany, do not consider it necessary to apply special control measures to GM organisms. Most likely, the first market for GM pigs will be China, where there is high demand for pork.
So far, the technology has serious drawbacks. Disabling MSTN causes health problems. Only 13 out of 32 pigs lived for 8 months, and only two are still alive. This disadvantage can be eliminated by disabling only one copy of the MSTN of the two, but then the weight of the muscles in GM pigs will be less.
Based on materials lenta.ru and zoom.cnews.ru
