Welcome back to the Abstract!You are all in for a treat this week. Scientists have opened up a new book of genomes and discovered a swashbuckling saga for the ages written inside. I dont even want to say anything more to spoil it. Im excited for you!Then, microplastics are in the air you breathe, the food you eat, and the grey neural matter you are using to read this sentence. But there is some hope on the horizon as humans have enlisted an unlikely hero (and occasional villain) to combat our plastic apocalypse.Next, scientists shed new light on the weird gap in our memories during the earliest years of life. I dont remember the rest. Last, does Arya Stark feel the Bern? Is Rey Palpatine coconut-pilled? Can anyone be coconut-pilled in the year 2025? I present a story about the political affiliations of fictional characters because that is much more palatable than confronting the political affiliations of real people.The Rime of the Ancient Mariner (Iguana Version)Scarpetta, Simon et al. Iguanas rafted more than 8,000 km from North America to Fiji. Proceedings of the National Academy of Sciences.Step aside, Odysseus. Theres a new epic in town about ocean voyagers braving impossible odds, charting unknown waters, and venturing to distant shores. And this time, the heroes arent warriors or gods. Theyre freakin iguanas.Thats right: Scientists have presented compelling evidence that Fijian iguanas (Brachylophus) are descendents of intrepid mariners that rafted across an astonishing 5,000 miles of the Pacific Ocean to reach their current idyllic homeland.By analyzing the genomes of iguanas around the world, the team discovered that the closest relatives of Fijian iguanas are North American desert iguanas (Dipsosaurus). This revelation suggests that, sometime within the past 34 million years, a common ancestor of both families was washed out to sea, probably from the coast of California or Mexico, on muddy mats of sticks and trees. The journey would have taken months, but enough of these iguanadventurers survived to colonize the Fijian archipelago.Iguanas are large-bodied herbivores that are well-known overwater dispersers, including species that colonized the Caribbean and the Galpagos islands, said researchers led by Simon Scarpetta of the University of San Francisco. However, the origin of Fijian iguanas had not been comprehensively tested."Our analyses strongly support the oceanic dispersal of Brachylophus from North America to Fiji, which is the greatest known oceanic dispersal event in the history of terrestrial vertebrates.Possible routes from North American to Fiji, with the most likely color-coded blue. Image: Simon Scarpetta and Jim McGuireWell, its the greatest ocean passage for terrestrial vertebrates besides all the human ones (sorry to pull rank, iguanas). But when humans go out to sea, it is generally intentional and involves a sturdy vessel and prepared provisions. These iguanas might have just been hanging out in a beachside tree one day when a bad storm hit, launching them into an accidental cross-oceanic cruise that changed the course of their lineage forever.So how did these lizards get their sea legs? Like, actually, what the heck? Months adrift on a tangle of wood and dirt? The answer, in short, is that iguanas are tenacious little thrillseekers that like to look death in the eye and laugh.Herbivorous iguanids forgo food for months at a time during brumationa form of reptile hibernationand extant Dipsosaurus brumate from OctoberMarch, said the study. However, floating vegetation mats are a known substrate for oceanic dispersal, so iguanas rafting from North America to Fiji could have had a food source during their journey.Additionally, some iguanas have other traits that may augment their capacity to survive overwater dispersal, including resistance to heat and dehydration, the researchers added. For example, Dipsosaurus have the highest voluntary thermal maximum temperature among lizards and largely inhabit areas without permanent freshwater.In other words, these seafaring lizards are hardy as hell. They could have either fasted as they rafted across one fifth of planet Earth, or perhaps subsisted on rations from an onboard mess hall.Either way, the reptiles stayed the course and were rewarded with an island paradise. Iguanas arent exactly known for their emotional expression, but I still cant help imagining their reaction to landing on terra firma after months of riding the waves. Surely, it was one small step for an iguana; one giant leap for iguana-kind.Boss Battle: E. Coli Versus PlasticChae, Tong Un et al. Biosynthesis of poly(ester amide)s in engineered Escherichia coli. Nature Chemical Biology.You may have seen a recent study that estimated that the average human brain contains enough microplastics to form a whole spoon if combined (about seven grams). Talk about neural plasticity! Ha ha ha.Okay, Ill stop. Because its not that funny. Nobody wants the equivalent of a plastic spoon in their brain. Its frankly ridiculous that weve let it get to the point where we all have plastic spoons in our brains. But petroleum-based plastic is just so convenient, which is why we make upwards of 400 trillion metric tons of it per year. This outflow, which will not biodegrade for centuries or longer, contaminates every conceivable corner of Earth (including your noggin) and is a big contributor to climate change.Who will save us from this self-inflicted body horror? Enter: Escherichia coli, better known by its stage name: E. coli. This microbe has a long rap sheet because it produces hazardous strains that contaminate our food, triggering product recalls and risking public health. Yes, this is bad, and nobody wants to contract the many maladies (some fatal) linked to E. coli.But E. coli contains multitudes. Most strains are totally harmless and the bacterium is a model organism that has been a goldmine for multiple fields. Now, scientists are enlisting the notorious microbe to help achieve the dream of engineering polyester amides (PEAs), which are a class of biodegradable polymers that deteriorate quickly compared to petroleum-based plastics.E. coli cultures. Image: HansNIn other words, this plastic replacement would not lodge any more utensils or assorted cookware into the brains of future generations (sorry, the spoon in your head is there to stay, and will indeed outlive your mortal form).To demonstrate the capability for sustainable PEA production, we engineered E. coli strains to produce proof-of-concept PEAs from glucose, a renewable resource derived from biomass, said researchers led by Tong Un Chae of the Korea Advanced Institute of Science and Technology (KAIST).This bacterial platform for the biobased production of various PEAsoffers several advantages over current chemical synthesis methods, the team said. Most importantly, it enables the sustainable production of PEAs, which is increasingly crucial as the climate crisis escalates.This study is just one of thousands of different efforts aimed at switching out petroleum plastics for biodegradable versions. Its hard to predict whether any of them will provide a scalable commercial option in the near-term, but it always lifts my spirits to see progress on this frontespecially when it gives E. coli a redemption arc. An occasionally deadly bacteria versus an indestructible symbol of human avarice? LET THEM FIGHT.The Gated Neighborhood on Memory LaneYates, Tristan et al. Hippocampal encoding of memories in human infants. Science.Lets stay on the subject of human brainsspecifically those without spoons. The only brains that meet this criteria are those of babies and toddlers, who havent had enough time to accumulate mental cutlery.This week, scientists investigated the fascinating mystery of infantile amnesia, which describes the strange recollective void in our lives as infants. Its not clear why most people cant remember experiences during this formative time, especially given that baby brains are super-powered learning machines in practically every other way.To shed light on this enigma, scientists examined the brains of infants aged from four months to two years old in magnetic resonance imaging (fMRI) machines. The goal was to see whether the hippocampus, a brain critical for memory, could encode memories, called engrams, at these young ages.By giving the young participants visual tests, the team documented fleeting engrams in the hippocampus starting at about one year of age. This discovery suggests infantile amnesia is caused by an inability to retrieve early memories later in life, rather than an inability to make and store them in the first place.Two of the studys authors during the fMRI experiment. Image: 160/90The results hint that the capacity to encode individual memories comes online during infancy, said researchers led by Tristan Yates of Columbia University. Our findings are consistent with recent studies in rodents showing that memory engrams formed during infancycan persist into adulthood but remain inaccessible at retrieval without direct stimulation or reminders.It turns out that there might be lots of those early memories still filed away somewhere in our heads, but they are behind walls, or locks, or other mental barriers. Theres something weirdly haunting about the concept of our baby memories floating aroundnot fully lost, but forever out of reach. What formative treasures are hidden in our neural folds?Then again, considering that I spent much of my early years eating dirt and getting stung by bees, maybe its best to let sleeping dogs lie.