From Ancient Plagues to Primitive Galaxies: Life's Deep History Continues to Rewrite the Rules

Biology & Medicine

• Ancient DNA analysis of 46 skeletons from four hunter-gatherer cemeteries near Lake Baikal in East Siberia revealed that plague was highly lethal and killing people as early as 5,500 years ago [15, 47]. The study found evidence of *Yersinia pestis* in at least 18 individuals—nearly 40 percent of the remains studied—challenging theories that outbreaks required high-density settlements [15, 47]. Furthermore, researchers identified a distinctive superantigen in the ancient plague strains, a toxin-producing genetic factor not found in later historic strains, suggesting these early infections could have been highly dangerous even before developing efficient flea-borne transmission [47]. ^[15][47]
• New fossil evidence from Mazon Creek suggests that early four-limbed vertebrates did not undergo metamorphosis when transitioning from water to land, challenging long-held assumptions about vertebrate evolution. Field Museum researchers Arjan Mann and Jason Pardo analyzed two juvenile embolomeres—a crocodile-like predator—found at the site, which lived between 307 million and 309 million years ago [25, 22]. These fossils showed that the animals retained many adult characteristics, including miniature legs and lacking external gills, indicating a pattern of direct development rather than a tadpole-like life phase [25, 22]. This finding suggests that the initial water-to-land transition for early tetrapods followed a different developmental path than previously assumed by scientists who had modeled the process after modern amphibians like frogs and salamanders [25, 22]. ^[25][22]
• Researchers at the University of Virginia School of Medicine analyzed over 350 over-the-counter probiotic supplements sold in the U.S., finding that these 352 products contained a collective total of only 36 unique species of bacteria, with forms of *Lactobacillus* being the most common type [7]. The study concluded there is no real consistency in the combination of species used to support claims for gut or vaginal health, despite many supplements containing only one probiotic species [7]. To improve product effectiveness, the team developed HaPaPro, a collection of over 1,000 computer models of bacterial metabolism, which successfully identified microbes with potential to help prevent bacterial vaginosis [7]. ^[7]