Group items matching

in title, tags, annotations or url

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.

But now, a century and a half later, scientists from 11 different institutions have joined forces to amass all of that information, plus new data, to create the most comprehensive version of the tree so far. As detailed in a recent article in Proceedings of the National Academy of Sciences, the new Tree of Life shows how 2.3 million different types of animals, plants, fungi and microbes are interconnected, and how those relationships have diverged since life began on Earth more than 3.5 billion years ago.

Want to know how much bacteria we host within our body and how many we encounter on a daily basis well check out this clip from Life On Us where we will see the different types of bacteria that inhabit us like Demodex Folliculorum which is a face mite...

In this clicker case study for a flipped classroom, students familiar with the stages of meiosis work in small groups to determine the predicted genetic makeup of the parthenogenetic offspring of a Komodo dragon, based on four different types of parthenogenesis. Students then learn about the actual genetic makeup of the offspring and determine how meiosis was modified to allow parthenogenesis in this fascinating lizard. The sex of the offspring is explained, based on ZW/ZZ sex determination. A video specifically made for this case prepares students for the in-class activities, which are guided by a PowerPoint presentation. The case also examines how facultative parthogenesis may be adaptive in Komodo dragons and the implications of facultative parthogenesis to conservation of these vulnerable lizards. The case was developed for a general biology class, but could also be used in an introductory course on conservation or cell biology.

This case study explores the topics of diffusion, osmosis, membrane transport, and the physiological significance of glucose and insulin in the human body. The story begins with a high school athlete, Timmy, who is incredibly efficient at metabolizing carbohydrates for energy; this is where the reader is introduced to normal carbohydrate digestion and metabolism for energy within skeletal muscle cells. As Timmy enters college, he withdraws from sports and physical activity but continues to consume massive amounts of highly soluble carbohydrates, resulting in insulin resistance and ultimately type II diabetes. Throughout the case students are prompted with conceptual questions and interactive figures that require the application and transfer of information they have been introduced to. Originally written for intermediate and advanced physiology courses that cover foundational and complex concepts in science, the case is also appropriate for courses in intermediate biology, nutritional sciences, animal sciences, and exercise sciences.

This lesson, using segments from the PBS series Faces of America, explores the various types of genetic information contained in the human genome. The Introductory Activity examines the structure and composition of chromosomes and DNA, and can be used as a review or introduction to the topic. Following that, students will participate in a hands-on activity reviewing basic Mendelian genetics and the difference between genotype and phenotype. Students will also learn about different ways of tracing ancestry through DNA, and apply that to patterns of human migration and genetic population sets known as haplogroups. In the Culminating Activity, students will develop methods for determining the genetic heritage of their class, school, or community.

Taxonomy is the study of scientific classification, in particular the classification of living organisms according to their natural relationships. Taxonomy's first father was the philosopher Aristotle (384-322 BC), sometimes called the "father of science." It was Aristotle who first introduced the two key concepts of taxonomy as we practice it today: classification of oranisms by type and binomial definition.

Panobinostat is a new type of drug that works by blocking an enzyme responsible for modifying DNA at the epigenetic level. Epigenetics refers to chemical marks on DNA itself or on the protein "spools" called histones that package DNA. These marks influence the activity of genes without changing the underlying sequence, essentially acting as volume knobs for genes. Earlier genomic studies showed that about 80 percent of DIPG tumors carry a mutation that alters a histone protein, resulting in changes to the way DNA is packaged and tagged with those chemical marks. This faulty epigenetic regulation results in activation of growth-promoting genes that should have been turned off, and shutdown of others that should have acted as brakes to cell multiplication. Cancer is the result. Panobinostat appears to work by restoring proper functioning of the cells' chemical tagging system.

"Reading and understanding scientific literature can be a daunting task for students in introductory science courses. This decision/dilemma case study helps ease them into the process by using a short scientific article with a simple experimental design that compares two types of ACL (anterior cruciate ligament) surgery, autograft and allograft. The case tells the story of Todd, a martial artist who recently tore his ACL in competition. With the help of the article, Todd discusses the potential surgical options provided by his doctor with his friend, Sam, a medical student. The case has the added value of demonstrating how one can use scientific literature to make informed healthcare decisions based on clinical evidence. Please note that the required article (Kane et al., Knee Surgery, Sports Traumatology, Arthroscopy 24(11): 3627-33) is not provided with this case; prior to assigning this material, instructors should confirm that students can access the article, since access may vary by institution."

In this interrupted case study, students meet a pair of fictional newlyweds on their way to Australia for their honeymoon. Initially eager to enjoy the sun, sand, and sights, Tanya and Julien Brahim end up more intimately acquainted with the local wildlife than they had planned. Tanya is bitten by a venomous arachnid and Julien has a run-in with a dangerous cnidarian. This case study was created to help students solidify their knowledge about cardiac myocytes, particularly ion movements associated with action potential generation in autorhythmic and contractile cells. As students work through the case, they will complete fill-in-the-blank paragraphs describing the heart, diagram membrane potentials and ion movements, and compare and contrast action potentials from different cell types. Written for a course in human physiology, the case requires some prior knowledge of membrane potentials, equilibrium potentials, ion gradients, neuronal action potentials, and skeletal muscle action potentials. An optional pre-case assignment (included in the teaching notes) can be used to make sure that students are familiar with the necessary concepts.

Most colon cancers may be caused by infections with bacteria that are normally found in cows. For decades we have known that Streptococcus gallolyticus gallolyticus (SGG) is sometimes found in colon tumours, but now the microbes have been found to directly cause tumour growth in mice.

The article "Data back ban of artificial trans fats" (10.8 readability score) summarizes new research showing that banning artificial trans fats in foods could reduce the risk of heart attacks and strokes. Students can focus on details reported in the article, follow connections to earlier articles about trans fats research, engage in a classroom discussion of related scientific and government policy questions and make connections between the science of food and their health. Students can also conduct their own experiments to analyze foods for fats and then research the types of fats within different foods to make recommendations about dietary consumption.

A common misconception is that Darwin suggested that something as complex as the eye could not have evolved through natural selection. While the misunderstanding often comes from an incomplete reading of his argument, we have long known that intermediate varieties of eyes (e.g., eyespots, cupped eyes, and complex camera-type eyes) exist in a variety of organisms. Eyes are so common that it was thought that they had evolved independently 40-60 times. More recent molecular work, however, has identified the role of Pax6 genes and their homologs in the formation of eyes during development. The basic information for eye formation appears to have been present in the common ancestor to all bilaterans, and perhaps may be more ancient than that. This interrupted case study examines the history of evidence for eye evolution from Darwin's initial postulates, through evidence of multiple intermediate forms, concluding in an examination of Pax6 homologs. The case is primarily for an introductory biology class but an additional section would be appropriate for upper-level evolution or developmental biology courses.

calorimetry carbon transfer: snails/elodea investigating bacterial growth mutations in fruit flys Gel Electrophoresis bacterial transformation comparing hominoid skulls testing antibacterial agents plant transpiration exploring plant responses insects and crime scene analysis interpreting bird response blood typing

Imagine you swallowed a small bird and suddenly gained the ability to fly … or you ate a cobra and were able to spit poisonous venom! Well, throughout the history of life (and specifically during the evolution of complex eukaryotic cells) things like this happened all the time. Adam Jacobson explains endosymbiosis, a type of symbiosis in which one symbiotic organism lives inside another.

This case study uses an interactive activity to illustrate density dependence in ecology classes. We developed a "hunt" using paper butterflies with warning signals on the upper side of the wings and symbols that indicate if a butterfly is noxious underneath the wings. Butterflies are distributed in four different patches with varying densities of noxious and palatable butterflies, simulating Batesian or Müllerian mimicry. Students can catch as many butterflies they want for a period of time, but if they catch more than three noxious butterflies they are out of the game. After the activity, students calculate the survival rate of each type of butterfly in each patch and discuss the implications of density and warning signals according to their results. Students then answer questions and build graphs using the data from the activity and knowledge from the class and the discussion. With this case study, students will be able to understand negative and positive density dependence, as well as predation, learning, and convergent evolution, while recalling or being introduced to Batesian and Müllerian mimicry.

This case study is designed to help students learn about the ecosystem services of Earth (Biosphere 1) by examining the challenges faced by the designers who tried to replicate its components in Biosphere 2. In 1991, four men and four women entered Biosphere 2, a man-made closed ecological system in Arizona, to see if eight biospherians could be sustained by this miniature version of Biosphere 1. The project succeeded in producing most of the food needed, but required additional oxygen before the end of the two-year experiment. After an introduction to Biosphere 2, students learn about the four main types of ecosystem services and discuss how Biosphere 2 might provide these services. At the end of the case, students calculate their own ecological footprint, demonstrating how humans are overreaching the ecosystem services of Biosphere 1, just as the biospherians could not be sustained by the ecosystem services included in Biosphere 2. The case is suitable for an introductory undergraduate course in biology, ecology, or environmental science.

o why are these lakes pink anyway? It's been a mystery for some years, but the puzzle's finally been cracked. Scientists found that pink bodies of water like Lake Hillier contain both Halobacteria and a type of algae known as Dunaliella salina, which thrive in salty environments like the pink lakes. The carotenoid red pigments secreted by Halobacteria and d. salina are responsible for the pink lakes' otherworldly colors. These same algae also flourish in the Dead Sea.

X-Spin Viral RNA Extraction Kit provides a fast an easy isolation method for the extraction and purification of nucleic acid (RNA) in samples. We are top RNA extraction kit manufacturer and offer viral rna extraction kits or rna Isolation kit covering many sample types and throughput needs.

n this interrupted case study, students learn about the influence of early fetal nutritional conditions on the expression of genes related to metabolism and growth. Beginning with the true event of a food and fuel embargo that led to famine in the western Netherlands toward the end of World War II, students learn about the historical background of the Dutch Hunger Winter and its social impact. Using real data from the study conducted by Heijmans and coauthors (2008), students then compare the methylation level of a specific gene between individuals conceived during the famine and their unaffected siblings, and how changes in the expression of this metabolically important gene may impact the risk of developing type 2 diabetes. Supported by other studies on mice and in humans, students conclude that in utero events may impact the health of individuals later in life through epigenetic mechanisms. The case is ideally suited for a molecular or cell biology course, but is also appropriate for an introductory biology course in which students have an understanding of descriptive statistics, interpretation of statistical test results, eukaryotic gene structure, and regulation of gene expression.