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nique mutations used to trace history back to its origins in the embryo Date: June 29, 2014

HIV jumped from apes to humans at least four times, as evidenced by genetically distinct groups of the virus that have been detected: M, N, O, and P. While N and P have had little impact, M is responsible for the pandemic affecting millions of individuals, and O has infected another 100,000.

What is the recipe for life? If you were to build a cell from scratch, what ingredients would you need? And what kind of environment would you need to cook inanimate matter into a living cell? These are the questions that occupy biochemist Jack Szostak, as he imagines the dynamic world where life was born.

Microbes 2,500 meters below the seafloor in Japan are most closely related to bacterial groups that thrive in forest soils on land, suggesting that they might be descendants of ones that survived when their terrestrial habitat was flooded 20 million years ago

In biology classes, students are typically taught that spontaneous generation does not take place. And yet, at the origin of life, life had to arise without parents from abiotic processes. What were those processes that gave rise to the first life?  This case study uses an interrupted format to guide students through the Miller-Urey experiment of 1953, which showed that organic molecules could be produced from abiotic precursors and conditions thought to be prevalent on the early Earth. The case also addresses the more speculative implications about where these reactions may have taken place to create the organic building blocks of life on this planet. The first three parts of the case, which explore the Miller-Urey experiment, are ideal for introductory biology courses and take about 45-50 minutes to complete. The remaining sections, which explore whether such chemical reactions took place in outer space, were used in a non-major astrobiology course and require a further hour to complete.

Shape of Life is a series of FREE short classroom videos that beautifully illustrate the evolution of the animal kingdom on planet earth. Based upon an original PBS Series, Shape of Life is especially designed for students and teachers who want a first-hand account of how animals adapt and thrive. The series is NGSS aligned with exquisite focus on diversity, biodiversity, adaptability, body structure, design, behaviors, and the innovative scientists who explore these creatures.

Shape of Life is a series of FREE short classroom videos that beautifully illustrate the evolution of the animal kingdom on planet earth. Based upon an original PBS Series, Shape of Life is especially designed for students and teachers who want a first-hand account of how animals adapt and thrive. The series is NGSS aligned with exquisite focus on diversity, biodiversity, adaptability, body structure, design, behaviors, and the innovative scientists who explore these creatures.

But if Gánti's theories had been more widely known during the communist era, he might now be acclaimed as one of the most innovative biologists of the 20th century. That's because he devised a model of the simplest possible living organism, which he called the chemoton, that points to an exciting explanation for how life on Earth began.

web based activity on speciation and adaptive radiation

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.

8' video on origins of life Paul Andersen describes how life could have formed on our planet through natural processes. The progression from monomers, to polymers, to protocells and finally to cells is described. The Miller-Urey experiment is described in detail as well as characteristics of the latest universal ancestor.

This interrupted case is based on a genome wide association study (GWAS) that identified the genetic variation causing some inhabitants of the Solomon Islands to have blond hair. The case illustrates the connection between genotype and phenotype, and an application of Hardy-Weinberg equilibrium. The narrative focusses on John and his new roommate, Peter, from the Solomon Islands who happens to have dark skin and blond hair. Using thought-provoking questions students learn about the genetics and the biochemistry of the hair color trait and how a single genetic variation can influence phenotype. Is migration or mutation involved?  Upon completion of the activity students will know the source of the genetic variation that causes the blond hair phenomenon in the Solomon Islands and if it has any European origins. The case was written for an upper-level genetics course, but could also be adapted for introductory biology or for a genetics course for non-majors. An optional PowerPoint presentation with clicker questions is available for download from within the Answer Key.

Could it be that Alzheimer's disease stems from the toxic remnants of the brain's attempt to fight off infection? Provocative new research by a team of investigators at Harvard leads to this startling hypothesis, which could explain the origins of plaque, the mysterious hard little balls that pockmark the brains of people with Alzheimer's.

A new study, published on Wednesday in Molecular Biology and Evolution, identifies gene variants in Inuit who live in Greenland, which may help them adapt to the cold by promoting heat-generating body fat. These variants possibly originated in the Denisovans, a group of archaic humans who, along with Neanderthals, diverged from modern humans about half a million years ago.

In this directed case study students follow a nurse practitioner and work with a diagnostics team to determine what is wrong with Tristan, an infant who comes to the clinic with multiple bruises. Students are given background and patient history, and are then given results of various blood tests ordered by the diagnostics team. The exercise emphasizes the physiological process of coagulation and the importance of various clotting factors, especially factor VIII. Students will be introduced to results from several blood tests, including: complete blood count, partial thromboplastin time, prothrombin time, metabolic panel, and factor VIII assay. The patient is ultimately diagnosed with severe hemophilia A and the case then introduces students to this disorder, the genetic determinants, the incidence, and ways to manage the disease. The data in this case are real and the story represents the medical history of an actual patient. Originally developed for pre-nursing students, this activity would also be suitable for majors in physiology or pre-medical students; it could also be used in an introductory genetics or biology course.

This indicates that the mutation originated in just one person who became the ancestor of all subsequent people in the world with blue eyes, according to a study by Professor Hans Eiberg and colleagues at the University of Copenhagen.

This interrupted case study introduces the topic of bacterial sporulation and cannibalism in Bacillus subtilis. The storyline follows Susan and her lab mates who are presenting research at a lab meeting when Susan falls asleep and dreams they are stranded on a deserted island. She makes connections between their fight for survival in the dream and the survival mechanisms of the bacteria they study in the lab. The benefits of sporulation under conditions of sustained stress are fairly obvious, but Susan's dream is used to examine the idea that sporulation may not always be beneficial and that bacteria would not want to commit to entering such a state in response to temporary stresses. Through the analysis of actual data from the scientific literature, students uncover a mechanism by which B. subtilis delays its commitment to sporulation by killing members of its own species to release nutrients (i.e., cannibalism). Originally developed for a general undergraduate microbiology course when discussing the structure and growth of prokaryotic cells, the case could also be used in an introductory biology course that emphasizes bacteria and data literacy.

Why do we smell different when we're sick? Why does cheese smell like feet? Why don't vultures get sick from eating rotting meat? Science is filled with stories: some of them are beautiful and some of them are gross. Really gross. Gross Science, a YouTube series hosted by Anna Rothschild, tells bizarre stories from the slimy, smelly, creepy world of science. In this collection, you'll find original short-form videos and DIY experiments from Gross Science, which is produced by NOVA and PBS Digital Studios. Learn about amphibians that eat their mother's skin, strange uses for bacon, how poop can be used to cure an infection, and more gross science topics.

Loss of species richness is often due to anthropogenic activity. The global decline of amphibians is one such example. This case study examines the impact of road deicing agents on amphibians living near bridges and roads treated heavily with salt during the winter months. Concepts explored in this case include changes to the aquatic environment as a result of road deicing applications, bioaccumulation, osmoregulation in amphibians living in clean freshwater, and the impact of increased aquatic salinity levels on the ability of amphibians to adequately osmoregulate in an environment for which they are not adapted. Three short videos created by the author can be shown in class or assigned for viewing in advance for a "flipped" classroom approach. Originally developed for a general education/introductory biology course, the case could also be used with introductory level animal anatomy and physiology courses as part of a deeper exploration of the renal system.

To address this issue, we have developed case studies that track the evolution of traits from their origination in DNA mutation, to the production of different proteins, to the fixation of alternate macroscopic phenotypes in reproductively isolated populations.

This case study was inspired by a real-life scenario, and follows the story of Roberto, a migrant farmworker whose health is impacted by the usage of pesticides on a farm.  With the help of a health care provider, Roberto becomes aware of the effects of pesticides on his well-being. Students utilize a database and draw conclusions from data in order to answer the case questions.  The case concludes with an activity that uses the "intimate debate" technique in which students use scientific data as evidence to argue whether or not the pesticide under discussion should be banned from usage.  This case was originally developed for undergraduate anatomy and physiology or toxicology courses. Students are expected to have some background knowledge in nerve structure and function as well as the mechanics of neural transmission before starting the case.