UC Berkeley
2022 Stories
Evolution of the plague pandemic
Over the summer, researchers announced that they’d identified the source of a deadly pandemic. This might sound like another story on COVID-19 – but in fact, the research did not focus on bats in China circa 2019, but on tombstones in Kyrgyzstan circa 1340. The Black Death, an outbreak of bubonic plague, killed perhaps as much as 60% of the population of Western Europe and Asia in less than 10 years. Bubonic plague is caused by the bacteria Yersinia pestis, which can spread through flea bites that transmit the microbe from one infected animal to another, as well as directly from person to person. This pandemic pestilence still lurks in rodents and other small animals around the world today, but now we treat the disease with antibiotics and understand its transmission well enough to tamp down outbreaks. However, many questions about the plague’s deadliest epidemic in the Late Middle Ages remain – mysteries to which ancient graves seemed to hold clues…
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Shrinking salmon
You can’t tell when it’s on your dinner plate, but wild salmon have been shrinking. Salmon from populations around the world now have smaller body sizes than they did 30 to 60 years ago. While the causes of this shift aren’t always clear, potential culprits include fishing, climate change, and competition for food (e.g., from hatchery-bred salmon). Now, new research untangles the probable causes of reduced body size in one population of wild Atlantic salmon – and demonstrates how the impacts of human activities can ripple through ecosystems.
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Preventing the evolution of a vaccine-resistant COVID strain
Many of us breathed a sigh of relief when COVID-19 vaccines rolled out. For those with the good luck of living in places with easy access, getting a shot or two could mean a fast track back to normal life — no more masks or social distancing. As vaccination rates went up, new cases fell, and social restrictions followed the same trend. It made sense to relax the rules we’d been living with once new virus cases slowed. However, recent research reveals potential evolutionary pitfalls in this approach.
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On the evolutionary trail of MRSA
The bacterium MRSA (shorthand for methicillin-resistant Staphylococcus aureus) resists several antibiotics and can cause super-charged staph infections, leading to difficult-to-treat skin infections, pneumonia, and sepsis. Antibiotic resistant bacteria like MRSA caused more than a million deaths in 2019. Now an international team of researchers has discovered what they think is the source of one variety of MRSA – and it didn’t come about through incremental evolution in people being treated with the antibiotic methicillin. It came from…hedgehogs.
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Omicron and the case of the hidden evolution
Over the past month, the SARS-CoV-2 Omicron strain has dominated world news. This fast-spreading coronavirus variant has led to travel restrictions, cancelled holiday plans, sold-out test kits, reimposed lockdowns, and of course, a staggering number of new COVID-19 cases. Scientists quickly pivoted to study Omicron, trying to learn how easily it spreads, how sick it makes us, and whether it resists our treatments, vaccines, and antibodies from previous COVID infections. We need to revisit all these questions because Omicron is very different from other coronavirus strains. Omicron has accumulated more than 50 new mutations in comparison to the strain that started the pandemic. Furthermore, Omicron is not descended from the Delta strain, which was responsible for the previous wave of infections. In fact, Omicron is so different from other variants that it seems like it’s been evolving on its own for many months. And that leads us to another mystery that scientists are puzzling over: where has Omicron been hiding while all this evolution was occurring?
Read more »Omicron y el caso de la evolución escondida
Durante el último mes, las cepas del SARS-CoV-2 Omicron han dominado los noticiarios del mundo. Esta variante de rápida transmisión ha llevado a limitar viajes, a cancelar planes de vacaciones, al agotamiento de los kits de pruebas, a la vuelta de los confinamientos, y además a un asombroso número de nuevos casos de COVID-19. Los científicos rápidamente se han puesto a estudiar Omicron, intentando entender qué tan rápido se transmite, qué tanto nos enferma, y si es resistente a los tratamientos, a las vacunas, y a los anticuerpos de infecciones de COVID previas. Necesitamos revisar todas estas cuestiones porque Omicron es muy diferente de otras cepas de coronavirus. Omicron ha acumulado más de 50 nuevas mutaciones en comparación con la cepa que empezó la pandemia. Además Omicron no es un descendiente de la cepa Delta, responsable de la anterior ola de infecciones. De hecho, Omicron es tan diferente de otras variantes que parece que ha estado evolucionando por su cuenta durante muchos meses. Y esto nos conduce a otro misterio que los científicos están tratando de resolver: ¿dónde estaba Omicron escondido mientras toda esta evolución tenía lugar?
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The evolution of tuskless elephants foils poachers, but at a cost
Between 1977 and 1992, a civil war in Mozambique killed over a million people, displaced five million more, and destroyed roads, schools, and hospitals. It also killed a lot of elephants. Armies need money to fight, and ivory from elephant tusks was a way to get it. The protected elephant population in Gorongosa National Park in Mozambique was decimated by ivory poachers. Before the war in 1972, the park was home to 2542 elephants. By the year 2000, that number had fallen to just 242. Now, recent research shows that poaching during this period caused rapid evolution in the elephant population, specifically, the rise of tuskless elephants.
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A decade of change, a decade of Evo in the News
In science, explanations like evolution are accepted or rejected based on evidence — and in that sphere, evolutionary theory has more than proven its worth. Experiments, field studies, observations, and fossils — all of it lines up behind the idea that different species evolved from shared ancestors and that natural selection and other evolutionary processes shape the traits of lineages. However, in the public sphere, particularly in the United States, evolutionary theory has not fared so well. Between around 1950 and 2007, surveys suggest that less than half of American adults accepted evolution. But that is changing. Researchers just announced that, over the last decade, we crossed over the halfway mark: the majority of American adults surveyed now report accepting evolution as an explanation for humans. The new research delves into factors that might help explain this shift, such as a rise in number of people enrolling in four-year college degree programs and college-level science courses. Here, we’ll focus on the evolutionary science that accompanied this uptick in acceptance.
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Pantry staples from the genetic swap meet
To many people, genetically engineered food feels unnatural and repellent: Fish genes in strawberries? No thanks. Opponents often call them “Frankenfoods,” suggesting that only a mad scientist could combine genes from different species in this way. But in recent decades, biologists have found that nature itself often plays fast and loose with DNA. The more we’ve looked, the more examples we’ve found where a gene from one species has made its way into another, sometimes distantly related, species. Now, new research shows how important this inter-species genetic swap meet has been in grasses, a group that includes food staples like rice, corn, wheat, and sugar cane.
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The genetic toolkit for evolving a venomous bite
If you scrolled past the non-stop coronavirus reporting in science news last month, you might have been hooked by some obvious clickbait “Humans will probably evolve to be venomous.” Uh…they will? Well, of course not. We needn’t worry about (or eagerly anticipate) becoming a lineage of fanged mutants. However, a look at the new research that inspired that extreme headline does provide a fascinating glimpse into how (and how easily) venom evolves in some situations.
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Viruses, variation, and vaccines
Last month, we discussed new strains of SARS-CoV-2 and how they evolved, despite the relatively slow pace of coronavirus evolution. Since then, the new strains have continued to spread and more have popped up. This month, with over 15% percent of the US at least partially vaccinated, we all want to know how effective the existing vaccines will be against those new strains. Will we need another shot for the new viral varieties in six months? And then again in a year? And so on indefinitely? As we face down a future that almost certainly means learning to coexist with the virus in some way, it’s worth asking a big-picture question: why do some vaccines successfully beat back a disease year after year and others do not?
Read more »Virus, variabilidad y vacunas
El mes pasado, hablamos sobre las nuevas cepas del SARS-CoV-2 y sobre cómo habían evolucionado, aunque su ritmo de evolución sea relativamente lento. Desde entonces, las cepas nuevas han seguido propagándose y algunas más han aparecido. Este mes, con cerca del 15% de la población de US, al menos, parcialmente vacunada, todos queremos saber la efectividad que tendrán las vacunas existentes contra estas nuevas cepas. ¿Dentro de seis meses necesitaremos otro pinchazo contra las nuevas variedades del virus? ¿Y al cabo de un año otra? ¿Y así indefinidamente? Mientras nos enfrentamos a un futuro que seguramente nos llevará a coexistir con el virus, vale la pena hacerse una pregunta general tiene sentido preguntarse sobre el gran escenario: ¿por qué algunas vacunas tienen éxito contra unas enfermedades año tras año, mientras que otras no?
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The new coronavirus strains and evolution’s “I told you so” moment
It seems like new coronavirus strains are suddenly popping up everywhere. These include the “UK” strain, a variant discovered in South Africa, two in Brazil, and now one in California, inspiring many anxious questions. Do these new strains spread more easily? At least some of them seem to. Are they more deadly? Evidence is just coming in but the British variant, at least, may be. Will our vaccines work against them? To varying degrees. Moderna is developing a booster shot to make its vaccine more effective against the strain from South Africa. As researchers try to sort out answers to these key questions, it’s worth taking a step back to ask how we got here. What’s the force behind all these new strains? Of course, the answer is evolution.
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