Genetics, from the word "Genesis" or "Origin", is the science of genes, heredity, and the variation of organisms. The word "genetics" was first suggested to describe the study of inheritance and the science of variation by the prominent British scientist William Bateson in a personal letter to Adam Sedgwick, dated April 18, 1905. Bateson first used the term "genetics" publicly at the Third International Conference on Genetics (London, England) in 1906.
Heredity and variations form the basis of genetics. Humans applied knowledge of genetics in prehistory with the domestication and breeding of plants and animals. In modern research, genetics provides important tools for the investigation of the function of a particular gene, e.g., analysis of genetic interactions. Within organisms, genetic information generally is carried in chromosomes, where it is represented in the chemical structure of particular DNA (deoxyribonucleic acid) molecules. Read more ...
Deoxyribonucleic acid DNA) is a molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), they are one of the four major types of macromolecules that are essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix.
The two DNA strands are termed polynucleotides since they are composed of simpler monomer units called nucleotides. Each nucleotide is composed of one of four nitrogen-containing nucleobases - either cytosine (C), guanine (G), adenine (A), or thymine (T) - and a sugar called deoxyribose and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. The nitrogenous bases of the two separate polynucleotide strands are bound together (according to base pairing rules (A with T, and C with G) with hydrogen bonds to make double-stranded DNA. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 trillion tons of carbon (TtC).
DNA stores biological information. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information. This information is replicated as and when the two strands separate. A large part of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve as patterns for protein sequences.
The two strands of DNA run in opposite directions to each other and are thus antiparallel. Attached to each sugar is one of four types of nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes biological information. RNA strands are created using DNA strands as a template in a process called transcription. Under the genetic code, these RNA strands are translated to specify the sequence of amino acids within proteins in a process called translation.
Within eukaryotic cells, DNA is organized into long structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, providing each cell its own complete set of chromosomes. Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm. Within the eukaryotic chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.
DNA was first isolated by Friedrich Miescher in 1869. Its molecular structure was identified by James Watson and Francis Crick in 1953, whose model-building efforts were guided by X-ray diffraction data acquired by Rosalind Franklin. DNA is used by researchers as a molecular tool to explore physical laws and theories, such as the ergodic theorem and the theory of elasticity. The unique material properties of DNA have made it an attractive molecule for material scientists and engineers interested in micro- and nano-fabrication. Among notable advances in this field are DNA origami and DNA-based hybrid materials. Read more
Gene Location for Paranoia Found Live Science - January 17, 2018
Our genes shape the way we look and how our bodies work, and looking at specific genes or snippets of DNA can offer scientists a glimpse of the control panels for many different physical traits. But researchers are still piecing together the relationship between genes and behavior, and indeed, little is known about how certain types of genes can influence human psychology. Recently, a rare disorder known as Prader-Willi syndrome (PWS) gave scientists an unprecedented opportunity to pinpoint the location of certain genetic activity associated with paranoia, a mental condition that frequently occurs in people with PWS. Many traits found in people with PWS — including paranoia — are associated with anomalies in two genes on a single chromosome. In a new study, scientists investigated the genetic makeup of people with the syndrome, noting which individuals exhibited more signs of paranoid behavior and looking for patterns in gene expression, which is the activation of information coded in a gene, to shape a particular trait.
Human immunity can kill the CRISPR gene therapy - but the technology is far from dead, expert says Daily Mail - January 8, 2018
The gene-editing technology some thought would change the nature of medicine may not be able to withstand the attacks of the human immune system, a new study suggests. The biotechnology, called CRISPR-Cas9, has been hailed as one of the greatest scientific developments of the last decade for its promising ability to edit or fix genetic mutations to treat - and perhaps some day prevent - diseases. Researchers at Stanford University sought to find out if the human body would reject cells after they had been edited using Cas9, an enzyme derived from bacteria, and reintroduced to the body. In the experiment, the human body recognized and destroyed the bacterial cells, but the scientists say we shouldn't write the technology off so quickly.
Researchers find genes may 'snowball' obesity Medical Express - December 7, 2017
There are nine genes that make you gain more weight if you already have a high body mass index. The effect of these genes may be amplified by four times, if we compare the 10% of the population at the low end of the body mass index, compared to the 10% at the high end. Although the increasing average body mass index of the population of several high-income countries has recently plateaued, the researchers note in the study, the cases of extreme forms of obesity are still growing. People who are morbidly obese are at risk of health complications such as diabetes, cardiovascular disease, hypertension and cancers and early death.
CRISPR-Cas9 technique targeting epigenetics reverses disease in mice Science Daily - December 7, 2017
Scientists report a modified CRISPR-Cas9 technique that alters the activity, rather than the underlying sequence, of disease-associated genes. The researchers demonstrate that this technique can be used in mice to treat several different diseases. Much of the enthusiasm around gene-editing techniques, particularly the CRISPR-Cas9 technology, centers on the ability to insert or remove genes or to repair disease-causing mutations. A major concern of the CRISPR-Cas9 approach, in which the double-stranded DNA molecule is cut, is how the cell responds to that cut and how it is repaired. With some frequency, this technique leaves new mutations in its wake with uncertain side effects.
Number of genetic markers linked to lifespan triples - 25 genetic variants linked to human longevity Science Daily - December 7, 2017
Researchers have studied 389,166 volunteers who gave DNA samples to the UK Biobank, US Health and Retirement Study and the Wisconsin Longitudinal Study. In addition to confirming the eight genetic variants that had already been linked to longevity, this study found 17 more to expand the list of known variants affecting lifespan to 25 genes, with some sex-specific.
Precise DNA editing made easy: New enzyme to rewrite the genome Science Daily - October 26, 2017
A new type of DNA editing enzyme lets scientists directly and permanently change single base pairs of DNA from A*T to G*C. The process could one day enable precise DNA surgery to correct mutations that cause human diseases. The newly created DNA base editor contains an atom-rearranging enzyme (red) that can change adenine into inosine (read and copied as guanine), guide RNA (green) which directs the molecule to the right spot, and Cas9 nickase (blue), which snips the opposing strand of DNA and tricks the cell into swapping the complementary base.
Genes responsible for diversity of human skin colors identified Science Daily - October 12, 2017
A study of diverse African groups by geneticists has identified new genetic variants associated with skin pigmentation. The findings help explain the vast range of skin color on the African continent, shed light on human evolution and inform an understanding of the genetic risk factors for conditions such as skin cancer.
DNA surgery on embryos removes disease BBC - September 29, 2017
Precise "chemical surgery" has been performed on human embryos to remove disease in a world first, Chinese researchers have told the BBC. The team used a technique called base editing to correct a single error out of the three billion "letters" of our genetic code. They altered lab-made embryos to remove the disease beta-thalassemia. The embryos were not implanted. The team says the approach may one day treat a range of inherited diseases. Base editing alters the fundamental building blocks of DNA: the four bases adenine, cytosine, guanine and thymine. They are commonly known by their respective letters, A, C, G and T. All the instructions for building and running the human body are encoded in combinations of those four bases.
Introducing ‘dark DNA' – the phenomenon that could change how we think about evolution The Conversation - September 14, 2017
But in some cases we're faced with a mystery. Some animal genomes seem to be missing certain genes, ones that appear in other similar species and must be present to keep the animals alive. These apparently missing genes have been dubbed 'dark DNA'. And its existence could change the way we think about evolution.
How One Man's Mutant DNA May Help End the Deadly Opioid Crisis NBC - August 1, 2017
Scientists say studying people like Steven Pete, who has a rare disorder that renders him insensitive to pain, may lead to nonaddictive painkillers.
Sixteen genetic markers can cut a life story short Science Daily - July 28, 2017
The answer to how long each of us will live is partly encoded in our genome. Researchers have identified 16 genetic markers associated with a decreased lifespan, including 14 new to science. This is the largest set of markers of lifespan uncovered to date. About 10% of the population carries some configurations of these markers that shorten their life by over a year compared with the population average. This study provides a powerful computational framework to uncover the genetics of our time of death, and ultimately of any disease.
10 Amazing Things Scientists Just Did with CRISPR Live Science - June 26, 2017
It's like someone has pressed fast-forward on the gene-editing field: A simple tool that scientists can wield to snip and edit DNA is speeding the pace of advancements that could lead to treating and preventing diseases.
CRISPR Editing of Human Embryos Brings Us Closer to GMO Babies Seeker - July 28, 2017
A new development in CRISPR technology ignites ethics debates about how much control we should have over our own genome. The first human embryos in the United States have been edited by the CRISPR-Cas9 system, according to an exclusive report by the MIT Technology Review. The results of the research haven't been published yet, so it's hard to establish exactly what happened. But if true, the research could herald a new era in human gene editing and experimentation.
Psychics do it all the time
Genes influence ability to read a person's mind from their eyes Science Daily - June 7, 2017
Our DNA influences our ability to read a person's thoughts and emotions from looking at their eyes, suggests a new study published in the journal Molecular Psychiatry. Twenty years ago, a team of scientists at the University of Cambridge developed a test of 'cognitive empathy' called the 'Reading the Mind in the Eyes' Test (or the Eyes Test, for short). This revealed that people can rapidly interpret what another person is thinking or feeling from looking at their eyes alone. It also showed that some of us are better at this than others, and that women on average score better on this test than men.
Now, the same team, working with the genetics company 23andMe along with scientists from France, Australia and the Netherlands, report results from a new study of performance on this test in 89,000 people across the world. The majority of these were 23andMe customers who consented to participate in research. The results confirmed that women on average do indeed score better on this test. More importantly, the team confirmed that our genes influence performance on the Eyes Test, and went further to identify genetic variants on chromosome 3 in women that are associated with their ability to "read the mind in the eyes."
First-ever look at DNA opening reveals initial stage of reading the genetic code PhysOrg - June 2, 2017
Scientists have watched a cell's genetic machinery in the first stages of 'reading' genes, giving a potential way to stop the process in bacteria. By reading certain genes - a process known as transcription - cells can produce and regulate proteins, which perform almost all the functions necessary for life.
DNA of extinct humans found in caves BBC - April 28, 2017
The DNA of extinct humans can be retrieved from sediments in caves - even in the absence of skeletal remains. Researchers found the genetic material in sediment samples collected from seven archaeological sites. The remains of ancient humans are often scarce, so the new findings could help scientists learn the identity of inhabitants at sites where only artifacts have been found. Researchers were able to identify the DNA of various animals belonging to 12 mammalian families, including extinct species such as the woolly mammoth, woolly rhinoceros, cave bear and cave hyena.
We Could Back Up The Entire Internet On A Gram Of DNA Seeker - March 16, 2017
Nature's code for life is stored in DNA, but what if we could code anything we wanted into DNA? Scientists are figuring out how.
Visualizing the genome: First 3-D structures of active DNA created Science Daily - March 13, 2017
Scientists have determined the first 3-D structures of intact mammalian genomes from individual cells, showing how the DNA from all the chromosomes intricately folds to fit together inside the cell nuclei. Most people are familiar with the well-known 'X' shape of chromosomes, but in fact chromosomes only take on this shape when the cell divides. Using their new approach, the researchers have now been able to determine the structures of active chromosomes inside the cell, and how they interact with each other to form an intact genome. This is important because knowledge of the way DNA folds inside the cell allows scientists to study how specific genes, and the DNA regions that control them, interact with each other. The genome's structure controls when and how strongly genes -- particular regions of the DNA -- are switched 'on' or 'off'. This plays a critical role in the development of organisms and also, when it goes awry, in disease.
Gene found to cause sudden death in young people Science Daily - March 9, 2017
A new gene that can lead to sudden death among young people and athletes has now been identified by an international team of researchers. The gene, called CDH2, causes arrhythmogenic right ventricle cardiomyopathy (ARVC), which is a genetic disorder that predisposes patients to cardiac arrest and is a major cause of unexpected death in seemingly healthy young people.
With stringent oversight, heritable human genome editing could be allowed Science Daily - February 14, 2017
Clinical trials for genome editing of the human germline -- adding, removing, or replacing DNA base pairs in gametes or early embryos -- could be permitted in the future, but only for serious conditions under stringent oversight, says a new report. Genome editing is not new. But new powerful, precise, and less costly genome editing tools, such as CRISPR/Cas9, have led to an explosion of new research opportunities and potential clinical applications, both heritable and non-heritable, to address a wide range of human health issues. Recognizing the promise and the concerns related to this technology, NAS and NAM appointed a study committee of international experts to examine the scientific, ethical, and governance issues surrounding human genome editing.
Genomes in flux: New study reveals hidden dynamics of bird and mammal DNA evolution PhysOrg - February 6, 2017
Evolution is often thought of as a gradual remodeling of the genome, the genetic blueprints for building an organism. But in some instance it might be more appropriate to call it an overhaul. Over the past 100 million years, the human lineage has lost one-fifth of its DNA, while an even greater amount was added. Until now, the extent to which our genome has expanded and contracted had been under-appreciated, masked by its relatively constant size over evolutionary time. Humans aren't the only ones with elastic genomes. A new look at a virtual zoo-full of animals, from hummingbirds to bats to elephants, suggests that most vertebrate genomes have the same accordion-like properties.
Organisms created with synthetic DNA pave way for entirely new life forms The Guardian - January 23, 2017
From the moment life gained a foothold on Earth its story has been written in a DNA code of four letters. With G, T, C and A - the molecules that pair up in the DNA helix - the lines between humans and all life on Earth are spelled out. Now, the first living organisms to thrive with an expanded genetic code have been made by researchers in work that paves the way for the creation and exploitation of entirely new life forms.
Hijacking the double helix for replication PhysOrg - December 13, 2016
For years, scientists have puzzled over what prompts the intertwined double-helix DNA to open its two strands and then start replication. Knowing this could be the key to understanding how organisms - from healthy cells to cancerous tumors - replicate and multiply for their survival. A group of USC scientists believe they have solved the mystery. Replication is prompted by a ring of proteins that bond with the DNA at a special location known as "origin DNA." The ring tightens around the strands and melts them to open up the DNA, initiating replication.
Twelve DNA areas linked with the age at which we have our first child and family size Medical Express - October 31, 2016
Researchers have identified 12 specific areas of the DNA sequence that are robustly related with the age at which we have our first child, and the total number of children we have during the course of our life. The study includes an analysis of 62 datasets with information from 238,064 men and women for age at first birth, and almost 330,000 men and women for the number of children. Until now, reproductive behavior was thought to be mainly linked to personal choices or social circumstances and environmental factors. However, this new research shows that genetic variants can be isolated and that there is also a biological basis for reproductive behavior.
Youthful DNA in old age Science Daily - September 22, 2016
The DNA of young people is regulated to express the right genes at the right time. With the passing of years, the regulation of the DNA gradually gets disrupted, which is an important cause of aging. A study of over 3,000 people shows that this is not true for everyone: there are people whose DNA appears youthful despite their advanced years.
Erasing unpleasant memories with a genetic switch Science Daily - June 30, 2016
Dementia, accidents, or traumatic events can make us lose the memories formed before the injury or the onset of the disease. Researchers have now shown that some memories can also be erased when one particular gene is switched off. In the reported study, the mice were trained to move from one side of a box to the other as soon as a lamp lights up, thus avoiding a foot stimulus. This learning process is called associative learning. Its most famous example is Pavlov's dog: conditioned to associate the sound of a bell with getting food, the dog starts salivating whenever it hears a bell. When the scientists switched off the neuroplastin gene after conditioning, the mice were no longer able to perform the task properly. In other words, they showed learning and memory deficits that were specifically related to associative learning. The control mice with the neuroplastin gene switched on, by contrast, could still do the task perfectly.
Researchers explore epigenetic influences of chronic pain Medical Express - June 21, 2016
Researchers at Drexel University College of Medicine are aiming to identify new molecular mechanisms involved in pain. Their latest study, published this month in Epigenetics & Chromatin, shows how one protein - acting as a master controller - can regulate the expression of a large number of genes that modulate pain. Epigenetics
First happiness genes have been located Science Daily - April 25, 2016
For the first time in history, researchers have isolated the parts of the human genome that could explain the differences in how humans experience happiness. These are the findings of a large-scale international study in over 298,000 people. The researchers found three genetic variants for happiness, two variants that can account for differences in symptoms of depression, and eleven locations on the human genome that could account for varying degrees of neuroticism. The genetic variants for happiness are mainly expressed in the central nervous system and the adrenal glands and pancreatic system. The results were published in the journal Nature Genetics.
More ancient viruses lurk in our DNA than we thought PhysOrg - March 22, 2016
Think your DNA is all human? Think again. And a new discovery suggests it's even less human than scientists previously thought. Think your DNA is all human? Think again. And a new discovery suggests it's even less human than scientists previously thought. Whether or not it can replicate, or reproduce, it isn't yet known. But other studies of ancient virus DNA have shown it can affect the humans who carry it. n addition to finding these new stretches, the scientists also confirmed 17 other pieces of virus DNA found in human genomes by other scientists in recent years. The study looked at the entire span of DNA, or genome, from people from around the world, including a large number from Africa - where the ancestors of modern humans originated before migrating around the world. The team used sophisticated techniques to compare key areas of each person's genome to the reference human genome.
Innate teaching skills 'part of human nature', study says PhysOrg - February 8, 2016
Some 40 years ago, Washington State University anthropologist Barry Hewlett noticed that when the Aka pygmies stopped to rest between hunts, parents would give their infants small axes, digging sticks and knives. To parents living in the developed world, this could be seen as irresponsible. But in all the intervening years, Hewlett has never seen an infant cut him- or herself. He has, however, seen the exercise as part of the Aka way of teaching, an activity that most researchers - from anthropologists to psychologists to biologists - consider rare or non-existent in such small-scale cultures. He has completed a small but novel study of the Aka, concluding that, teaching is part of the human genome.
Error Found in Study of First Ancient African Genome Scientific American - January 30, 2016
An error has forced researchers to go back on their claim that humans across the whole of Africa carry DNA inherited from Eurasian immigrants. This week the authors issued a note explaining the mistake in their October 2015 Science paper on the genome of a 4,500-year-old man from Ethiopia - the first complete ancient human genome from Africa. The man was named after Mota Cave, where his remains were found. Although the first humans left Africa some 100,000 years ago, a study published in 2013 found that some came back again around 3,000 years ago; this reverse migration has left its trace in African genomes. In the Science paper, researchers confirmed this finding. The paper also suggested that populations across the continent still harbour significant ancestry from the Middle Eastern farmers who were behind the back-migration. Populations in East Africa, including Ethiopian highlanders who live near Mota Cave, carried the highest levels of Eurasian ancestry. But the team also found vestiges of the ‘backflow' migration in West Africans and in a pygmy group in Central Africa, the Mbuti.
Genes for a longer, healthier life found Science Daily - December 1, 2015
Out of a 'haystack' of 40,000 genes from three different organisms, scientists have found genes that are involved in physical aging. If you influence only one of these genes, the healthy lifespan of laboratory animals is extended -- and possibly that of humans, too. DNA strand. Driven by the quest for eternal youth, humankind has spent centuries obsessed with the question of how it is exactly that we age. With advancements in molecular genetic methods in recent decades, the search for the genes involved in the aging process has greatly accelerated.
Heart disease gene 'found in women' BBC - October 21, 2015
Scientists have identified a gene that puts women at higher risk of heart disease, an early study suggests. The work showed that women who had a particular version of the BCAR1 gene were more likely than other women to have heart attacks and strokes. In contrast, men who had the gene were not at increased risk.
Extra DNA acts as a 'spare tire' for our genomes Science Daily - July 6, 2015
Carrying around a spare tire is a good thing -- you never know when you'll get a flat. Turns out we're all carrying around 'spare tires' in our genomes, too. Today researchers report that an extra set of guanines (or 'G's) in our DNA may function just like a 'spare' to help prevent many cancers from developing.
Longer Life May Lie in Number of Anti-Inflammatory Genes Live Science - April 8, 2015
Why do some kinds of animals live longer than others? For mammals, part of the answer may lie in the number of anti-inflammatory genes. From mouse to man - and across 12 other mammal species examined - researchers found that those with more copies of genes called CD33rSIGLEC, which is involved in fighting inflammation, have a longer life span. Moreover, mice that researchers bred to have fewer copies of these genes experience premature aging and early death compared with normal mice, the study found.
Breast Cancer Genes: How Much Risk Do BRCA Mutations Bring? Live Science - April 8, 2015
Women with mutations in the BRCA1 and BRCA2 genes are at increased risk for breast and ovarian cancer, but a woman's exact cancer risk may vary greatly depending on exactly how her gene is mutated, or changed from its original form. A new study identifies a number of mutations in the BRCA1 and BRCA2 genes that may help doctors provide women with more precise estimates of their cancer risk. "We have women who are 70 and 80 years old who have BRCA1 [or] BRCA2 mutations and have never developed cancer of any kind," said study researcher Timothy Rebbeck, a professor of epidemiology at the University of Pennsylvania's Perelman School of Medicine. "If we can give more precise risk estimates," this may help women with their decisions, Rebbeck said.
New study hints at spontaneous appearance of primordial DNA PhysOrg - April 7, 2015
The self-organization properties of DNA-like molecular fragments four billion years ago may have guided their own growth into repeating chemical chains long enough to act as a basis for primitive life. While studies of ancient mineral formations contain evidence for the evolution of bacteria from 3.5 to 3.8 billion years ago - just half a billion years after the stabilization of Earth's crust - what might have preceded the formation of such unicellular organisms is still a mystery. The new findings suggest a novel scenario for the non-biological origins of nucleic acids, which are the building blocks of living organisms.
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