Month: February 2021

Enlarge / This interpretive sign at the presumed "fort clearing" includes a reconstruction of what the fort probably looked like in 1804. (credit: National Park Service)

In 1804, Tlingit warriors sheltered behind the walls of a wooden fort on a peninsula in southeastern Alaska, preparing to repel a Russian amphibious assault. An archaeological survey near the modern community of Sitka recently revealed the hidden outline of the now-legendary fort, whose exact location had been lost to history since shortly after the battle.

The coolest battle you never heard of

The Tlingit had already sent Russia packing once, in 1802, after three years of mounting tensions over the Russian-American Trading Company (a venture akin to the better-known British East India Company), which had a presence on what’s now called Baranof Island. Because the Tlingit elders—especially a shaman named Stoonook—suspected that the Russian troops would soon be back in greater numbers, they organized construction of a fort at the mouth of the Kaasdaheen River to help defend the area against assault from the sea.

By 1804, the Tlingit had procured firearms, shot, gunpowder, and even cannons from American and British traders. They had also built a trapezoid-shaped palisade, 75 meters long and 30 meters wide, out of young spruce logs, which sheltered more than a dozen log buildings. The Tlingit dubbed it Shis’gi Noow—the Sapling Fort.

Enlarge / The structure of the SARS-CoV-2 spike protein. (credit: University of Arkansas)

Over the summer, you could almost hear a sigh of relief rising from the portion of the research community that was tracking the evolution of the SARS-CoV-2 virus. Viruses, especially those new to their hosts, often pick up mutations that help them adapt to their new habitat, or they evade drugs or immune attacks. But SARS-CoV-2 seemed to be picking up mutations at a relatively sedate pace, in part because its virus-copying enzymes had a feature that lets them correct some errors.

But suddenly, new variants appear to be everywhere, and a number of them appear to increase the threat posed by the virus. A new study helps explain the apparent difference: while new base changes in the virus' genetic material remain rare, some deletions of several bases appear to have evolved multiple times, indicating that evolution was selecting for them. The research team behind this new work found evidence that these changes alter how the immune system can respond to the virus.

This looks familiar

The researchers' interest in deletions started with their involvement with an immunocompromised cancer patient, who held off the infection for over two months without being able to clear the virus. Samples obtained from late in the infection revealed two different virus strains that each had a deletion in the gene encoding the spike protein that SARS-CoV-2 uses to attach to and enter cells.