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Researchers led by Terra D. Barnes of Washington University discovered that their genetically-engineered mice stutter due to DNA defects in a humdrum "housekeeping" gene. This gene codes for a protein that simply places a "routing tag" on certain enzymes that shred cellular trash. The tag ensures that the shredding enzymes end up in chambers called lysosomes, basically the cell's garbage disposal. It's a mundane cellular activity, yet mutations in the same process in humans have also been linked to stuttering-a bizarrely specific condition for such a general gene. And, so far, scientists have no idea why the two are linked.

The short film opens with two questions: "So what determines how many species live in a given place? Or how many individuals of the species can live somewhere?" The research that provided answers to these questions was set in motion by key experiments by ecologists Robert Paine and James Estes. Robert Paine's starfish exclusion experiments on the coast of Washington state showed that removing starfish from this marine ecosystem has a big impact on the population sizes of other species, establishing the starfish as a keystone species. James Estes and colleague John Palmisano discovered that the kelp forest ecosystems of the North Pacific are regulated by the presence or absence of sea otters, which feed on sea urchins that consume kelp. These direct and indirect effects of sea otters on other species describe a trophic cascade. These early studies were the inspiration for hundreds of investigations on other keystone species and trophic cascades, as well as ongoing studies into the regulation of population sizes and species numbers.

GMOs are organisms that have had their DNA modified through genetic engineering. This is often done by taking a gene from one organism and putting it into another one to alter it in a desirable way. For example, when genetic engineers want to create a corn crop that is resistant to pests, they seek out the trait in Bacillus thuringiensis (Bt) soil bacteria that naturally acts as a pesticide. From there, engineers isolate the gene responsible for that trait and directly insert it into the corn's DNA. This corn is then bred with other corn until it's ready to be produced for consumption.

The groundwater is cold, deep and twice as salty as seawater, but the water streaming out of Blood Falls, which teems with microbes, tells us that it is unlikely to be lifeless. "The fact that the [water] contains metabolically active micro-organisms that appear to be suited to life in a dark, cold brine supports the idea that life should persist throughout the subsurface," says Mikucki. If so, those microbes could be fuelling life in the Southern Ocean. By breaking down iron-containing rocks they might be dumping as much as 170 million kilograms of iron into the ocean each year, according to the researchers' estimates, helping to explain why marine productivity is seasonally very high near to the coast.

The early stages of embryonic development shape our cells and tissues for life. It is during this time that our newly formed cells are transformed into heart, skin, nerve or other cell types. Scientists are finding that this process is largely controlled not by the genome, but by the epigenome, chemical markers on DNA that tell cells when to turn genes on and off. Now, studying zebrafish embryos, researchers at Washington University School of Medicine in St. Louis have shown that the epigenome plays a significant part in guiding development in the first 24 hours after fertilization.

These 106 in-depth tutorials are designed to illustrate and explain some of the many complex topics in biology. Each tutorial has four elements: an introduction that describes the topic to be illustrated and puts it into a broader context, a detailed animation that clearly illustrates the topic (there are a few tutorials that include simulations or other types of content, rather than animations), a conclusion that summarizes what you should have learned from the animation, and a quiz on the topic covered.

The study is the first to find that people's bodies metabolize bisphenol-A (BPA) - a chemical found in most people and used in polycarbonate plastic, food cans and paper receipts - into something that impacts our cells and may make us fat. The research, from Health Canada, challenges an untested assumption that our liver metabolizes BPA into a form that doesn't impact our health.

myBrainshark is a superb tool that allows students to add a voiceover to PowerPoint presentations, Word documents, videos and photo albums -- or to simply produce podcasts. It then blends the visual and audio components together into a video presentation. In the classroom, your students can present completed projects using myBrainshark, rather than face-to-face, or they can use it for mock presentations allowing the teacher to give feedback before the real presentation. The former can help bolster the confidence and communication skills of introverted and/or passive learners. Teachers can also turn their PowerPoint presentations into narrated video presentations (e.g. explanation of concepts) that students can watch outside of school hours. The most immediate limitation of this tool is that presentations cannot be downloaded in the free version. If you are looking for a tool that also allows for video narratives along with PowerPoint presentations (instead of basic audio), I would suggest Present.me.

Anthracobunidae is an Eocene family of large mammals from south Asia that is commonly considered to be part of the radiation that gave rise to elephants (proboscideans) and sea cows (sirenians). We describe a new collection of anthracobunid fossils from Middle Eocene rocks of Indo-Pakistan that more than doubles the number of known anthracobunid fossils and challenges their putative relationships, instead implying that they are stem perissodactyls.

Although genetic factors contribute to congenital heart disease, many children born with heart defects have healthy parents and siblings, suggesting that new mutations that arise spontaneously -- known as de novo mutations -- might contribute to the disease. New research shows that about 10 percent of these defects are caused by genetic mutations that are absent in the parents of affected children.

The question of cell renewal is one that all of us have intuitive daily experience with. We all notice that our hair falls out regularly, yet we don't get bald (at least not until males reach a certain age!).  Similarly, we have all had the experience of cutting ourselves only to see how new cells replaced their damaged predecessors. And we donate blood or give blood samples without gradually draining our circulatory system. All of these examples point to a replacement rate of cells, that is characteristic of different tissues and in different conditions, but which makes it abundantly clear that for many cell types renewal is a part of their story.

SciGuides are a collection of thematically aligned lesson plans, simulations, and web-based resources for teachers to use with their students centered on standards-aligned science concepts. Human modifications to communities of living organisms in an ecosystem can change the function and processes of that system. The flow of energy through an ecosystem depends upon the diversity of organisms within it; therefore, when this flow is altered, substantial biological and geological changes occur. It is important that our students not only realize that when a local ecosystem is destroyed or negatively affected by human transformations (building, agriculture, technology); the effect is eventually felt globally. We cannot ignore the fact that everything we do impacts our natural environment. The main question is, "How can we be better "keepers of the Earth"?

For the second time in four months, researchers have reported autopsy results that suggest Alzheimer's disease might occasionally be transmitted to people during certain medical treatments-although scientists say that neither set of findings is conclusive. The latest autopsies, described in the Swiss Medical Weekly on January 26, were conducted on the brains of seven people who died of the rare, brain-wasting Creutzfeldt-Jakob disease (CJD). Decades before their deaths, the individuals had all received surgical grafts of dura mater-the membrane that covers the brain and spinal cord. These grafts had been prepared from human cadavers and were contaminated with the prion protein that causes CJD.

Scientists have genetically engineered monkeys so that they exhibit behaviors similar to autism, with a goal of testing potential therapies on the animals in hopes that their resemblance to humans will yield more answers about the disorder. The scientists found that the monkeys showed "very similar behaviors related to human autism patients, including repetitive behaviors, increased anxiety and, most importantly, defects in social interactions," said Zilong Qiu, a leader of the research at the Institute of Neuroscience at the Chinese Academy of Sciences in Shanghai. The team is now imaging the brains of the monkeys, he said, "trying to identify the deficiency in the brain circuits that is responsible for the autism-like behavior."

The purpose of this case is to teach introductory college biology students the basic process of mitosis, focusing on the fundamental cellular processes that occur during each of the stages-prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis. It would also be appropriate for AP Biology students. The case is framed around solving a murder. The murder plot involves a naturally-occurring poison derived from Yew trees, known as paclitaxel. Paclitaxel is a mitotic inhibitor that works by inhibiting the depolymerization of microtubules so that the cell is arrested in metaphase. At the end of the case, students will be able to describe the basic process of mitosis, including the fundamental processes that occur in each stage. The discovery of paclitaxel led to the development of the chemotherapeutic drug, Taxol ®, and the case concludes by having students think about the correlations between poisons and chemotherapies. The case involves the use of videos, one of which was made by the author for this case, and can be used in a flipped classroom.

But this tiny sample turned out to hold tremendous scientific value. It was from a person fortunate to survive the deadly Ebola virus outbreak of 2014. Walker and her colleagues wanted to know if they could identify some special antibodies in that person's blood. If this person had special Ebola-neutralizing antibodies, that might help explain why that person lived. The antibodies might also help provide a template for future development of a vaccine. Or, they could be the basis for genetically engineered copies that could be manufactured at large scale, stockpiled and used to rescue people newly infected in an outbreak.

Technical details aside, Crispr-Cas9 makes it easy, cheap, and fast to move genes around-any genes, in any living thing, from bacteria to people. "These are monumental moments in the history of biomedical research," Baltimore says. "They don't happen every day." Using the three-year-old technique, researchers have already reversed mutations that cause blindness, stopped cancer cells from multiplying, and made cells impervious to the virus that causes AIDS. Agronomists have rendered wheat invulnerable to killer fungi like powdery mildew, hinting at engineered staple crops that can feed a population of 9 billion on an ever-warmer planet. Bioengineers have used Crispr to alter the DNA of yeast so that it consumes plant matter and excretes ethanol, promising an end to reliance on petrochemicals. Startups devoted to Crispr have launched. International pharmaceutical and agricultural companies have spun up Crispr R&D. Two of the most powerful universities in the US are engaged in a vicious war over the basic patent.

Quintana-Murci and his colleagues also took advantage of a previously published map of areas of the human genome where Neanderthal genes are present, showing that innate immune genes are generally more likely to have been borrowed from Neanderthals than genes coding other types of proteins. Specifically, they noted that 126 innate immune genes in present-day Europeans, Asians, or both groups were among the top 5 percent of genes in the genome of each population most likely to have originated in Neanderthals. The cluster of toll-like receptor genes, encoding TLR 1, TLR 6, and TLR 10, both showed signs of having been borrowed from Neanderthals and having picked up adaptive mutations at various points in history. Meanwhile, a group led by Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, used both the same previously published Neanderthal introgression map that Quintana-Murci used and a second introgression map. The researchers searched for borrowed regions of the genome that were especially long and common in present-day humans, eventually zeroing in TLR6, TLR10, and TLR1. These receptors, which detect conserved microbial proteins such as flagellin, are all encoded along the same segment of DNA on chromosome four.

This clicker case addresses several concepts related to the evolutionary ecology of herbivore defenses. A survey of several different studies that investigated chemical defenses in Thymus vulgaris (thyme) gives students the opportunity to develop hypotheses, pose potential experiments, and interpret data to develop a better understanding of not only herbivore deterrence, but also how natural selection can involve different pressures selecting for different phenotypes. The case study incorporates group discussion, analysis of experimental design, and data evaluation as central activities. It can be taught in a single 50-minute class session, an economy that is achieved in part by using a "flipped" approach. Students prepare outside of class by watching several short videos (one of which was made by the author) that teach the basics of herbivore deterrence and abiotic and biotic forces in the environment that can influence plant adaptations. The case study was designed for use in a large introductory-level class, but would also be appropriate for smaller classes or upper-level evolution courses.

It concludes that the so-called stimulus-triggered acquisition of pluripotency (STAP) stem cells, as well as the chimeric mice and teratomas supposedly derived from those cells, "all originated in cultures contaminated with (embryonic stem) cells, a fact that refutes all of the main conclusions of the two papers" that reported the the supposed breakthrough method of reprogramming adult cells. Those two papers, an article and a letter, appeared online in Nature on 29 January.