The CRISPR Revolution [ungated: 1,2,3] - "Biologists continue to hone their tools for deleting, replacing or otherwise editing DNA and a strategy called CRISPR has quickly become one of the most popular ways to do genome engineering. Utilizing a modified bacterial protein and a RNA that guides it to a specific DNA sequence, the CRISPR system provides unprecedented control over genes in many species, including perhaps humans. This control has allowed many new types of experiments, but also raised questions about what CRISPR can enable." [more inside]
I’m occasionally told my life would be easier if I backed off from my relentless efforts to advance evolution education. Maybe so. But to shy away from emphasizing evolutionary biology is to fail as a biology teacher. I continue to teach biology as I do, because biology makes sense only in the light of evolution.
Troubles in Paradise is a review of the history and arguments of the creationism/intelligent design movement, written by James Downard.
I waited silently for her to explain that the female pelvis is shaped slightly differently from the male’s, with a larger opening for childbearing. That part was the giveaway. The real purpose of the exercise was to make her prove her conjecture with measurements--to translate the theory to practice. I also wanted her to explain why this sexual dimorphism--that is, this sexually determined physical difference--is not nearly so pronounced in nonhuman primates, such as chimpanzees.When teacher Robert S. Root-Bernstein got this answer to his question on how you should distinguish between male and female skeletons, he had to find a way to make her realise her error without disparaging her religion.
She spoke: Males have one fewer pair of ribs than females.
You invest so much in it, don't you? It's what elevates you above the beasts of the field, it's what makes you special. Homo sapiens, you call yourself. Wise Man. Do you even know what it is, this consciousness you cite in your own exaltation? Do you even know what it's for?Dr. Peter Watts is no stranger to MetaFilter. But look past his sardonic nuptials, heartbreaking eulogies, and agonizing run-ins with fascists (and fasciitis) and you'll find one of the most brilliant, compelling, and disquieting science fiction authors at work today. A marine biologist skilled at deep background research, his acclaimed 2006 novel Blindsight [full text] -- a cerebral "first contact" tale led by a diverse crew of bleeding-edge post-humans -- is diamond-hard and deeply horrifying, wringing profound existential dread from such abstruse concepts as the Chinese Room, the Philosophical Zombie, Chernoff faces, and the myriad quirks and blind spots that haunt the human mind. But Blindsight's last, shattering insight is not the end of the story -- along with crew/ship/"Firefall" notes, a blackly funny in-universe lecture on resurrecting sociopathic vampirism (PDF - prev.), and a rigorously-cited (and spoiler-laden) reference section, tomorrow will see the release of
Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome. Naturalists first became aware of our invisible lodgers in the 1600s, but it wasn’t until the past few years that we’ve become really familiar with them. This recent research has given the microbiome a cuddly kind of fame. We’ve come to appreciate how beneficial our microbes are — breaking down our food, fighting off infections and nurturing our immune system. It’s a lovely, invisible garden we should be tending for our own well-being. But in the journal Bioessays, a team of scientists has raised a creepier possibility. Perhaps our menagerie of germs is also influencing our behavior in order to advance its own evolutionary success — giving us cravings for certain foods, for example.[more inside]
Koryos, who previously explained how cats got domesticated using tumblr, now explains why homosexual pair-bonding can be a successful reproductive stratagem. Also, Coot Parenting Tips, Queen Cowbird Of The Brood Parasites , There's No Such Thing As An Alpha Wolf, and Can Animals Have Pets?
With growing fascination for the large land vertebratomorphs that are so startlingly diverse on Tatooine, I secured Imperial funding for an expedition to Tatooine, to survey the exotic megafauna and search for fossils of Tyrannodraconis that might further illuminate their evolution. My ensuing report summarizes my trilogy of investigations and discoveries from this “holiday in the suns." [more inside]
"Peter and Rosemary Grant are members of a very small scientific tribe: people who have seen evolution happen right before their eyes."
Evolutionary biologists at Northumbria University have used science to figure out "attractive human dance moves" that demonstrate optimum genotypic and phenotypic health to prospective mates. "Cutting-edge motion capture technology" was used to record good and bad dancing. (Technoviking was reportedly unpleased.)
Bill Nye is debating the head of the Creation Museum tomorrow. Ken Ham, founder of Northern Kentucky tourist attraction "Answers in Genesis" Creation Museum, has challenged Science Guy Bill Nye to a duel, errr, a debate. Nye, while tolerant of Ham's religious beliefs, draws the line at creationism creeping into science curriculum. More pre-event throwdowns are here. [more inside]
This 419-Million-Year-Old Fish Has the World’s Oldest Known Face What makes it remarkable is everything that’s come after it: It’s the oldest known creature with a face, and may have given rise to virtually all the faces that have followed in the hundreds of millions of years since, including our own.
In March 2012, inspectors from the U.S. Department of Agriculture uncovered a problem in Elgin, Texas. Beef sausage from a small family-run meat processor appeared to have been contaminated with a nasty bacterium called Listeria monocytogenes. The bug can make people sick and, in rare cases, be deadly. The processor had to recall more than a ton of sausage. It’s the kind of story that strikes terror in the hearts of other sausage peddlers, including Mike Satzow, so he uses phages to keep his small company's sausages safe to eat.
Unleashing Genetic Algorithms on the iOS 7 Icon - In the pursuit of something just a bit tighter than Marc Edwards' superellipse approximation, Mike Swanson applies genetic algorithms to the task of making a better button-making script.
In the past few days, the Internet has been filled with commentary on whether the National Science Foundation should have paid for my study on duck genitalia, and 88.7 percent of respondents to a Fox news online poll agreed that studying duck genitalia is wasteful government spending. The commentary supporting and decrying the study continues to grow. As the lead investigator in this research, I would like to weigh in on the controversy and offer some insights into the process of research funding by the NSF.
Come for the passionate defense of basic science, stay for the explosive eversion of a duck penis.[more inside]
With incisor-like claws that can tunnel beneath your skin in seconds, ticks are rapidly establishing themselves as the Swiss Army knife of disease vectors. Carl Zimmer walks into the woods to find out why these tiny beasts appear to be skyrocketing in number – and outsmarting environmental scientists trying to control them with every bite.
Researchers have found that size does matter as it relates to overall proportions of the male body (PNAS link, PDF)
seaQuest: what if we could learn to live on/underneath the oceans (or in orbit)? [previously(er)] [more inside]
To put a human face on our ancestors, scientists from the Senckenberg Research Institute used sophisticated methods to form 27 model heads based on tiny bone fragments, teeth and skulls collected from across the globe. Here is a video showing those different models morphing into one another. Original article here. [via] [more inside]
"Hundreds (maybe thousands) of spiders congregate between poles in the town of Santo Antonio de Plantina / PR." [more inside]
Dougal Dixon is a scientist, author, and illustrator. While he is most famous for his work on dinosaurs, his books After Man: A Zoology of the Future and Man After Man: An Anthropology Of The Future attempt to explore what might happen in the far future. The Posthuman Art Of Dougal Dixon. [more inside]
Group selection, which was once widely rejected as a significant evolutionary force, is now accepted by all who seriously study the subject. There is still widespread confusion about group selection, however, not only among students and the general public, but among professional evolutionists who do not directly study the subject. We list eight criticisms that are frequently invoked against group selection, which can be permanently laid to rest based upon current knowledge. Experts will always find something to critique about group selection, as for any important subject, but these eight criticisms are not among them. Laying them to rest will enable authors to openly use the term group selection without being handicapped during the review process. [HTML], [PDF]
The Norovirus: A Study in Puked Perfection, "Each norovirus carries just nine protein-coding genes (you have about 20,000). Even with that skimpy genetic toolkit, noroviruses can break the locks on our cells, slip in, and hack our own DNA to make new noroviruses. The details of this invasion are sketchy, alas, because scientists haven’t figured out a good way to rear noroviruses in human cells in their labs. It’s not even clear exactly which type of cell they invade once they reach the gut. Regardless of the type, they clearly know how to exploit their hosts. Noroviruses come roaring out of the infected cells in vast numbers. And then they come roaring out of the body. Within a day of infection, noroviruses have rewired our digestive system so that stuff comes flying out from both ends." [more inside]
Woese once said of himself and his work that when a wise man points out the moon, only a fool looks at the finger. Let us all be fools if just for a moment .
Microbiology's Scarred Revolutionary(PDF), Carl Woese (pron.: /ˈwoʊz/), a biophysicist and evolutionary microbiologist whose discovery 35 years ago of a “third domain” of life in the vast realm of micro-organisms altered scientific understanding of evolution, died on Sunday at his home in Urbana, Ill. He was 84. [more inside]
Deciphering the Tools of Nature’s Zombies: The ability of parasites to alter the behaviour of their hosts fascinates both scientists and non-scientists alike. One reason that this topic resonates with so many is that it touches on core philosophical issues such as the existence of free will. If the mind is merely a machine, then it can be controlled by any entity that understands the code and has access to the machinery. This special issue of The Journal of Experimental Biology highlights some of the best-understood examples of parasite-induced changes in host brain and behaviour, encompassing both invertebrate and vertebrate hosts and micro- and macro-parasites. Full issue annotated inside: [more inside]
In just a few weeks single-celled yeast have evolved into a multicellular organism, complete with division of labour between cells. This suggests that the evolutionary leap to multicellularity may be a surprisingly small hurdle. More from Scientific American blogs. [Full Text PDF of the Publication of Note] [more inside]
State of the Species: Will the unprecedented success of Homo sapiens lead to an unavoidable downfall? [Via]
One of the many problems farmers of various kinds of legumes need to deal with is the pea aphid. They reproduce incredibly fast and live by sucking the sap out of the plants, an electron micrograph of one in action. However, while they are terrifying parasites of legumes, they have their own yet more horrific parasites, a parasitoid wasp. Here is a really nice close up picture of one doing its thing, a video of the act, and here is a brain meltingly horrific video of a dissection of the mummified aftermath 8 days later. Essentially, these wasps deposit their eggs in a pea aphid and the growing larva feeds on it, developing there for about a week, and then consuming the host from the inside out like a Xenomorph. When it’s done, the wasp larva dries the aphid’s cuticle into a papery brittle shell and an adult wasp emerges from the aphid mummy. Legume farmers love them, and you can even order their mummies online these days. However, farmers noticed that the wasps didn't work as effectively on all of the aphids, and so researchers went to work figuring out why. It turns out that all aphids have a primary bacterial endosymbiont living inside their cells, in addition to and just like a mitochondria, and that many have some combination of five other secondary endosymbionts. Interestingly, two of those other five, Hamiltonella defensa and Serratia symbiotica have been shown to confer varying levels of resistance to the parasitoid wasp, allowing the aphid to survive infection. However, it turns out that there is yet one more layer to this story, [more inside]
In this sprightly talk (transcript and video) Daniel Lieberman describes why our bodies are so good at running long distances, how our social intelligence developed and how modernity and capitalism require us to learn (or relearn) how to use our bodies. (May inspire tolerance for people who wear five-fingered shoes.) Prof. Lieberman studies human evolution at Harvard where he focuses on heads and feet. (via Tyler Cowen)
The Puzzle of Plastid Evolution: A comprehensive understanding of the origin and spread of plastids remains an important yet elusive goal in the field of eukaryotic evolution. Combined with the discovery of new photosynthetic and non-photosynthetic protist lineages, the results of recent taxonomically broad phylogenomic studies suggest that a re-shuffling of higher-level eukaryote systematics is in order. Consequently, new models of plastid evolution involving ancient secondary and tertiary endosymbioses are needed to explain the full spectrum of photosynthetic eukaryotes. [Full Text HTML] [Full Text PDF] [more inside]
Mitigating Mutational Meltdown in Mammalian Mitochondria PLoS Biol 6(2): e35. [The PDF, where you can read the paper in its much prettier intended format.]
Mitochondria are remarkable microorganisms. About two billion years ago, their distant free-living ancestors hooked up with a truly foreign lineage of archaebacteria and started a genomic merger that led to the most successful coevolved mutualism on the planet: the eukaryotic cell. Along the way, evolving mitochondria lost a lot of genomic baggage, entrusted their emerging hosts with their own replication, sorted out genomic conflicts by following maternal inheritance, and have mostly abstained from sex and recombination. What mitochondria did retain was a subset of genes that encode critical components of the electron transport chain and ATP synthesis enzymes that carry out oxidative phosphorylation. Because mitochondria house the biochemical machinery that requires us to breathe oxygen, it was first assumed that mitochondrial genes would show very slow rates of molecular evolution. So it was big news almost 30 years ago when mitochondrial DNA (mtDNA) evolution was observed to be quite rapid . How could the genes for a highly conserved and critical function sustain the consequences of high mutation pressure and permit rapid rates of nucleotide substitution between species? Without the benefits of recombination, where offspring can carry fewer mutations than either parent, mutations should accumulate in mitochondrial genomes through the random loss of less-mutated genomes, a process referred to as Muller's ratchet [2,3]. How have mitochondria avoided a mutational meltdown, or at least significant declines in fitness?Here is a jaw droppingly beautiful 3D animation of what Mitochindria look like in action. [more inside]
Constitutive formation of caveolae in a bacterium. [Full Text]
Caveolin plays an essential role in the formation of characteristic surface pits, caveolae, which cover the surface of many animal cells. The fundamental principles of caveola formation are only slowly emerging. Here we show that caveolin expression in a prokaryotic host lacking any intracellular membrane system drives the formation of cytoplasmic vesicles containing polymeric caveolin. Vesicle formation is induced by expression of wild-type caveolins, but not caveolin mutants defective in caveola formation in mammalian systems. In addition, cryoelectron tomography shows that the induced membrane domains are equivalent in size and caveolin density to native caveolae and reveals a possible polyhedral arrangement of caveolin oligomers. The caveolin-induced vesicles or heterologous caveolae (h-caveolae) form by budding in from the cytoplasmic membrane, generating a membrane domain with distinct lipid composition. Periplasmic solutes are encapsulated in the budding h-caveola, and purified h-caveolae can be tailored to be targeted to specific cells of interest.Elio Schaechter writes in plain English about how fantastically amazing and unexpected the researchers actually pulling this off is, and he also talks about it in more detail in his podcast.
Provirophages and transpovirons as the diverse mobilome of giant viruses
Abstract: A distinct class of infectious agents, the virophages1 that infect giant viruses of the Mimiviridae family, has been recently described. Here we report the simultaneous discovery of a giant virus of Acanthamoeba polyphaga (Lentille virus) that contains an integrated genome2 of a virophage (Sputnik 2), and a member of a previously unknown class of mobile genetic elements3, the transpovirons4. The transpovirons are linear DNA elements of ∼7 kb [kilobases]5 that encompass six to eight protein-coding genes, two of which are homologous6 to virophage genes. Fluorescence7 in situ hybridization8 showed that the free form of the transpoviron replicates within the giant virus factory and accumulates in high copy numbers inside giant virus particles, Sputnik 2 particles, and amoeba cytoplasm. Analysis of deep-sequencing data showed that the virophage and the transpoviron can integrate9 in nearly any place in the chromosome of the giant virus host and that, although less frequently, the transpoviron can also be linked to the virophage chromosome. In addition, integrated fragments of transpoviron DNA were detected in several giant virus and Sputnik genomes. Analysis of 19 Mimivirus strains revealed three distinct transpovirons associated with three subgroups of Mimiviruses. The virophage, the transpoviron, and the previously identified self-splicing introns10 and inteins11 constitute the complex, interconnected mobilome12 of the giant viruses and are likely to substantially contribute to interviral gene transfer.[Full Text PDF] and two explanations in English [more inside]
"In an effort to outwit raccoons, are we pushing their brain development and perhaps even sending them down a new evolutionary path? Using high-definition, infrared cameras that turn pitch dark into daylight ... Raccoon Nation [alt link] achieves something that has never been done before: it intimately follows a family of urban raccoons over the course of six months as the young – under the watchful eye of their mother – grow, develop, and begin to find their way in the complex world of a big city." "Raccoon populations have grown twenty-fold in North American cities over the last seventy years. And as this documentary will show, city life is changing raccoons in remarkable ways." (45:08 min. video)
"I attempted to repeat the experiment, however once my assistant discovered that I didn’t really have any tuna, she declined to participate in any further tests."
The Pliocene Pussy Cat Theory (which originally appeared in The Annals of Improbable Research) argues that the human ancestor Australopithecus domesticated cats for hunting, defense and harvesting static electricity to make it easier to climb trees. The theory, which was proposed by Lorenzo Love, is a parody of the Aquatic Ape Hypothesis (which is critiqued here and in shorter form here). Whether you know about the Aquatic Ape Hypothesis or not, the Pliocene Pussy Cat Theory, and Love's follow-up, the Subterranean Ape Theory, will completely alter your understanding of human evolution.
Nature constantly engineers new and creative solutions to all sorts of problems—turning our stereotypes about sex upside-down along the way.
Bill Nye recently described in a Youtube video why he thinks that Creationism is inappropriate for children. Representatives of the Creation Museum have a response.
Trees of Life: A Visual History of Evolution Trees of Life: A Visual History of Evolution catalogs 230 tree-like branching diagrams, culled from 450 years of mankind’s visual curiosity about the living world and our quest to understand the complex ecosystem we share with other organisms, from bacteria to birds, microbes to mammals. (More trees are visible at the Google Books site.)