WASHINGTON, Dec 5 (Reuters) — Hundreds of thousands of people worldwide are killed annually by malaria and other diseases spread through the bite of mosquitoes, insects that date back to the age of dinosaurs. All of these bites are inflicted by females, which possess specialized mouth anatomy that their male counterparts lack.

But it has not always been that way. Researchers said they have discovered the oldest-known fossils of mosquitoes — two males entombed in pieces of amber dating to 130 million years ago during the Cretaceous Period and found near the town of Hammana in Lebanon. To their surprise, the male mosquitoes possessed elongated piercing-sucking mouthparts seen now only in females.

“Clearly they were hematophagous,” meaning blood-eaters, said paleontologist Dany Azar of the Chinese Academy of Sciences’ Nanjing Institute of Geology and Paleontology and Lebanese University, lead author of the study published this week in the journal Current Biology. “So this discovery is a major one in the evolutionary history of mosquitoes.”

Nearly four years into the pandemic, hundreds of Americans are still dying every day from Covid, according to the Centers for Disease Control and Prevention ( CDC).

The virus is responsible for around 1,000 deaths and 15,000 hospitalisations each week, CDC Director Mandy Cohen said during a media briefing on 2 December.

Death rates briefly dipped below 500 per week in July, the lowest rates since the pandemic began, before steadily increasing to as high as 1,400 in September.

Long-term data from a study implemented by the # NIH-funded International Maternal Pediatric Adolescent AIDS Clinical Trials Network showed very early antiretroviral therapy (ART) for infants who acquired HIV in utero enabled some infants to sustain viral suppression for more than two years.

---

Very early ART for in-utero HIV-1 can achieve sustained virological suppression in association with biomarkers indicating restricted HIV-1 reservoirs by age 2 years, which might enable potential ART-free remission.

However, when major genome rearrangements occur — like the ones that the team was seeing in the skate’s DNA — boundaries can be lost, and the relative positions of genes on chromosomes can change. As a result, “some enhancers can provide instructions to the wrong gene,” explained Dario Lupiáñez, an evolutionary biologist at the Max Delbrück Center in Berlin and one of the senior authors of the study.

It seemed possible that the changes in the 3D architecture of the skate genome might have disrupted the ancient blocks of genes the skates inherited from their sharklike ancestors, affecting the genes’ function. “We were trying to look at whether some genome rearrangements in the little skate actually break these blocks,” said Ferdinand Marlétaz, a genomicist at University College London and co-first author of the study.

“It is particularly challenging, expensive, and time-consuming to find polar bears in the Arctic, let alone count them and understand how they are coping with climate change,” said Dr. Melanie Lancaster.

---

Can scientists use DNA from polar bear footprints to help improve conservation efforts during this age of climate change? This is what a recent study published in Frontiers in Conservation Science hopes to address as a team of international researchers have developed a novel tool designed to use DNA from polar bear footprint skin cells with the goal of tracking the large mammals without the need to capture them, which often risks the safety of both the polar bears and their human captors in the process. This study holds the potential to develop new methods in tracking animals whose populations are at risk as climate change continues to warm the planet.

Polar bear near Utqiagvik, Alaska in May 2022. (Credit: Elisabeth Kruger, World Wildlife Fund)

The World Wildlife Fund (WWF) currently estimates 22,000–31,000 polar bears worldwide, which are divided into 19 distinct sub-populations while classifying a “vulnerable” risk to polar bears on the international scale, along with having this same classification for Greenland, Denmark, and Norway. Additionally, they are polar bears are classified as “threatened” in the United States, “recovering” in Russia, and “special concern” in Canada, the last of which 60–80 percent of polar bears reside. As noted, capturing or trapping polar bears can be extremely dangerous, with previous methods using low-flying helicopters to dart polar bears.