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An anti-malaria breakthrough

August 26, 2025 By EarthWise Leave a Comment

The deadliest animal in the world is the mosquito. Mosquitos infected 263 million people with malaria in 2023, leading to 600,000 deaths, 80% of which were children. Malaria is caused by infection from Plasmodium parasites. The parasites are transmitted to humans from the bite of infected female mosquitos.

Researchers at the University of California San Diego, Johns Hopkins University, UC Berkeley, and the University of Sāo Paulo have developed a new method that genetically blocks mosquitos from transmitting malaria.

The study was published in the journal Nature. They used gene editing to change a single molecule within mosquitos. The genetically altered mosquitos can still bite people with malaria and can still acquire parasites from their blood, but the parasites can no longer be spread to other people. The switching of one specific amino acid known as L224 with a genetic alternative called Q224 prevents malarial parasites from reaching the salivary glands of the mosquito, thereby preventing the spread of infection. In extensive tests, the researchers found that while the genetic switch disrupted the parasite’s infection capabilities, the mosquitos’ normal growth and reproduction remained unchanged.

The hope is that the replacement of a single amino acid in mosquitoes that prevents them from being infected with malarial parasites is a beneficial trait that can spread throughout a mosquito population. The researchers believe that the trait can be spread across diverse mosquito species and populations and can pave the way for adaptable, real-world strategies to control malaria.

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Stealth Genetic Switch in Mosquitoes Halts Malaria Spread

Photo, posted June 20, 2014, courtesy of John Tann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hope for white rhinos

February 28, 2024 By EarthWise Leave a Comment

There are only two northern white rhinos left in the world, and both of them are female. The last male died in 2018. Northern white rhinos live to about 40 and one of the two remaining is 35 and the other 24. The clock is ticking for the species.

Recently, scientists with the BioRescue consortium successfully used in vitro fertilization to impregnate a southern white rhino. It was the world’s first IVF rhino pregnancy.

There is now some hope that IVF could be used to produce more northern white rhinos. For various medical reasons, neither of the remaining two female rhinos can serve as a surrogate mother. But there is a plan B.

For a number of years, BioRescue has been creating northern white rhino embryos with eggs from the remaining females and sperm that was collected from males before they died. There are now 30 northern white rhino embryos in cold storage, and they are continuing to produce more.

The recent success with the southern white rhino IVF provides hope that southern white rhino females can act as surrogate mothers with implanted northern white rhino embryos. The species are similar enough that it should work.

The plan is to select surrogates and implant them. This should happen this year. A rhino pregnancy lasts 16 months. If this is successful, there could be northern white rhino babies in two or three years. The scientists want the offspring to live with the surviving northern whites for years to learn the social behavior of its kind.

It is possible that these gentle, hulking creatures may get a new lease on life.

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Just two northern white rhinos are left on Earth. A new breakthrough offers hope

Photo, posted September 16, 2017, courtesy of San Diego Zoo Safari Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lots of female turtles

November 3, 2023 By EarthWise Leave a Comment

Green sea turtles were listed under the Endangered Species Act in 1978. Since that time, there have been conservation measures put in place in many locations. One such place is Florida, where restrictions on beachfront development and careful monitoring of turtle nests has helped to get hatchlings safely into the water. A gill net ban in 1995 sharply reduced the number of young turtles killed by fishing gear.

All of this has resulted in what is described as an explosion in turtle populations in Florida. Volunteers monitoring the 2023 nesting season on Florida’s beaches have counted more than 74,000 nests. That beats the previous record – set in 2017 – by an incredible 40%.

Unfortunately, this does not represent a guaranteed great future for the species. Sea turtles are particularly sensitive to the warming climate. The sex of a baby sea turtle is not determined by DNA, but rather by the temperature of the sand in which its egg develops. Cooler temperatures mean more males; warmer ones mean more females.

In recent years, the proportion of male green sea turtles has dwindled substantially. In the past few seasons, between 87 percent and 100 percent of the hatchlings tested in Florida have been female.

In the short term, the skewed sex ratio might be a boon for the species. Lots of females laying lots of eggs means lots of turtles. Sea turtles don’t reach sexual maturity until their twenties or thirties. So, for the next few decades, there are likely to be growing numbers of turtle nests. But down the line, there is going to be a real problem. Where will for all the female turtles find the mates to populate the species in the future?

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Florida Turtle Nests Are Recovering. When They Hatch, Expect Mostly Girls.

Photo, posted October 5, 2011, courtesy of Keenan Adams / USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio