Genetic Disorders HMMI BioInteractive DNA Animation Adenine (A), cytosine (C), guanine (G), and thymine (T) are the components of nucleic acid that make up DNA. In 1950, Erwin Chargaff published a paper stating that in the DNA of any given species, the ratio of adenine to thymine is equal, as is the ratio of cytosine to guanine. This became known as Chargaff's ratio, and it was an important clue for solving the structure of DNA. Chronic myeloid leukemia (CML) is caused by a mutation that leads to an abnormal protein that is always active. Of the 3 billion letters in the human genome, only 1% directly code for proteins. Reactive molecules, such as free radicals, and solar ultraviolet radiation can lead to mutations in DNA. A new gene can be inserted into a loop of bacterial DNA called a plasmid. The human genome is organized into structures called chromosomes, consisting of 22 matching pairs and one pair of sex chromosomes. Once a gene has been transcribed into messenger RNA (mRNA), it is edited in a process called splicing.
Did natural selection make the Dutch the tallest people on the planet? AMSTERDAM—Insecure about your height? You may want to avoid this tiny country by the North Sea, whose population has gained an impressive 20 centimeters in the past 150 years and is now officially the tallest on the planet. Scientists chalk up most of that increase to rising wealth, a rich diet, and good health care, but a new study suggests something else is going on as well: The Dutch growth spurt may be an example of human evolution in action. The study, published online today in the Proceedings of the Royal Society B, shows that tall Dutch men on average have more children than their shorter counterparts, and that more of their children survive. "This study drives home the message that the human population is still subject to natural selection," says Stephen Stearns, an evolutionary biologist at Yale University who wasn't involved in the study. For many years, the U.S. population was the tallest in the world. Just how these peoples became so tall isn't clear, however.
Gene Therapy|Genomics and Medicine Course|Biology Lecture Material To view the lecture material accompanying this lecture in a new window, please click the button below. If necessary, use the vertical or horizontal scrollbar in the new window to view more of the material or you can resize the window. To download the above lecture material use this link. (Right-click and select Save Target As or Save Link As.) Supplementary lecture material is listed below. 1. Discussion Forum For discussion on this topic, please go to the relevant forum for Genomics and Medicine. Genetics Course|Biology Course Summary This course is based on 7.03 Genetics, Fall 2004 made available by Massachusetts Institute of Technology: MIT OpenCourseWare under the Creative Commons BY-NC-SA license. This course discusses the principles of genetics with application to the study of biological function at the level of molecules, cells, and multicellular organisms, including humans. The topics include: structure and function of genes, chromosomes and genomes, biological variation resulting from recombination, mutation, and selection, population genetics, use of genetic methods to analyze protein function, gene regulation and inherited disease. Reading Material 1. Course Material Not available. Other Resources 1. Software
Might Alien Life Evolve Like the Incredible Octopus? by Natalie Shoemaker Consider the octopus: a creepy skeleton-less creature with limbs that have regenerative properties and a mind of their own. Its structure — inside and out — makes it like no other animal on earth. As a part of the Mollusca phylum, the octopus seems so far removed from its clam cousin. Neurobiologist Benny Hochner, from the Hebrew University of Jerusalem in Israel, talked about this oddity in an interview with Alison Abbott from Nature: “Very simple molluscs like the clam — they just sit in the mud, filtering food. Scientists have marveled at the octopus for years, and now they've taken the time to delve deeper into its biology by decoding its genome. "The octopus appears so utterly different from all other animals, even ones it's related to, that the British zoologist Martin Wells famously called it an alien. “It’s important for us to know the genome, because it gives us insights into how the sophisticated cognitive skills of octopuses evolved.”
DNA Deoxyribonucleic acid (DNA) is a long chain organic molecule that contains the coding for all metabolic and reproductive processes of all living organisms, save for certain viruses. This helix shaped molecule consists of a spine that contains a sequence of nucleotides, whose order comprise the coding instruction for each specific lifeform. DNA itself is not alive, but holds the instruction set for building a vast array of proteins as well as its own replication. By governing the synthesis of proteins, DNA is inherently the key substance for the maintenance and replication of every cell in nature, as well as DNA-containing viruses that subsist in another organism's host cells. A single DNA molecule contains all the information required to assemble any complete organism; in fact, the macro-structure of circular versus linear DNA geometry distinguishes biological domains (e.g. prokaryote versus eukaryote). Double helix DNA model The double helix Sense and anti-sense strands Supercoiling
DNA study shows Celts are not a unique genetic group 18 March 2015Last updated at 14:00 ET By Pallab Ghosh Science correspondent, BBC News "What's fascinated historians is why over such a short space of land, the people are so different", as Pallab Ghosh reports A DNA study of Britons has shown that genetically there is not a unique Celtic group of people in the UK. According to the data, those of Celtic ancestry in Scotland and Cornwall are more similar to the English than they are to other Celtic groups. The study also describes distinct genetic differences across the UK, which reflect regional identities. And it shows that the invading Anglo Saxons did not wipe out the Britons of 1,500 years ago, but mixed with them. Published in the Journal Nature, the findings emerge from a detailed DNA analysis of 2,000 mostly middle-aged Caucasian people living across the UK. Continue reading the main story “Start Quote End QuoteProf Mark RobinsonOxford University Striking similarities Who do you think you are? Continue reading the main story
Making of Europe unlocked by DNA DNA sequenced from nearly 40 ancient skeletons has shed light on the complex prehistoric events that shaped modern European populations. A study of remains from Central Europe suggests the foundations of the modern gene pool were laid down between 4,000 and 2,000 BC - in Neolithic times. These changes were likely brought about by the rapid growth and movement of some populations. The work by an international team is published in Nature Communications. Decades of study of the DNA patterns of modern Europeans suggests two major events in prehistory significantly affected the continent's genetic landscape: its initial peopling by hunter-gatherers in Palaeolithic times (35,000 years ago) and a wave of migration by Near Eastern farmers some 6,000 years ago. Family tree The latest paper reveals that events some time after the initial migration of farmers into Europe did indeed have a major impact on the modern gene pool. Haplogroup H dominates mtDNA variation in Europe. Migrant wave
Gene drives spread their wings Genies are said to have the power to grant three wishes. But genies recently released from laboratory flasks promise to fulfill nearly any wish a biologist can dream up. End the scourge of insect-borne diseases? Check. These genies aren’t magical; they are research tools known as gene drives — clever bits of engineered DNA designed to propel themselves into the DNA of a pesky or troubled organism. Gene drive enthusiasts say these genies could wipe out malaria, saving more than half a million lives each year. Scientists have sought the power of gene drives for decades. “Everything is possible with CRISPR,” says geneticist Hugo Bellen. But genes designed to spread through populations and alter ecosystems could have unforeseen consequences. As yet, no CRISPR gene drive has been released in the wild — few have even been built. Story continues after graphic Rule breakers Gene drives aren’t naked DNA floating around the air and water. Story continues after table Engines of change Fast forward