Links for Keyword: Genes & Behavior

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By Michael Schulson Last spring, Paul Strode gave an unusual survey to his advanced biology students at Fairview High School in Boulder, Colorado. The first five questions were: 1. Define as best you can: What is a racial group? 2. Define as best you can: What is an ethnic group? 3. Define as best you can: What is meant by the term genetic ancestry? 4. True or False: There is too much overlap between racial groups to use a single biological trait (like skin color) to distinguish one racial group from another. 5. True or False: When several traits are combined they can be used to distinguish one racial group from another. “In terms of wading into the idea of gender identification, differences between racial groups and so forth, we regard those as potential firestorms, if we were to go there.” The next day, Strode showed his students — all seniors — their aggregated results. On some questions, the students were mostly in agreement. More than 80 percent of them, for example, correctly marked Question 4 as “True.” But other topics were muddier, and on several questions — including #5 — the students split nearly 50-50. “They’re guessing,” Strode says. (For the record, the answer he says he was looking for on #5 was “False.”) Strode’s exercise is an anomaly. Most American biology textbooks and curricula don’t discuss race at all — nor do they grapple with the biology of sexual orientation or gender, for that matter. To some, these omissions seem appropriate. Early 20th-century biology textbooks, after all, were replete with ignorant racial and gender stereotyping and classifications purporting to be scientific — and some even extolled the virtues of racial purity. It would be hard to find such discussions in today’s biology classrooms and supporting materials. Copyright 2018 Undark

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 25444 - Posted: 09.13.2018

Philip Ball Carl Zimmer is a rarity among professional science writers in being influential among the scientists on whose work he writes and comments – to the extent that he has been appointed as professor adjunct in the department of molecular biophysics and biochemistry at Yale University. Zimmer has just published his 13th book, She Has Her Mother’s Laugh, a survey of “the power, perversions and potential of heredity”. What is the book’s main message about our attitudes to heredity? Heredity is central to our existence and how we define ourselves. But it’s not what we think it is. It’s not just genes, for example. We inherit culture too, and there may even be other channels of heredity. And the way genes enable heredity doesn’t fit our common notions. We tend to imagine that we inherit particular genes from our parents, grandparents and so on, and that these shape us in ways that are easy to understand and trace. But that’s not how heredity works. Each trait is typically influenced by hundreds or thousands of different genes, and the environment in which those genes are acting makes all the difference to how we turn out. You talk in the book about how some of these questions were brought home to you when your first daughter was born in 2001. What’s your personal journey into the story of heredity? In 2000 my wife was pregnant with our first child, and our doctor asked us to go to a genetics counsellor. I thought this was pointless. But the counsellor started asking me questions and I suddenly realised I had a really terrible grasp of my family history. I felt very ashamed and irresponsible, because here was this child who would be inheriting a lot of my genes. This was the first time heredity went from being something I learned about in class to one of the most important things in my existence. © 2018 Guardian News and Media Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 25325 - Posted: 08.13.2018

Laurel Hamers A Nobel Prize–winning discovery — that small double-stranded RNA molecules can silence genes by interrupting the translation of DNA’s instructions into proteins — is finally delivering on its medical promise. The first drug that takes advantage of this natural biological process, called RNA interference, was approved August 10 by the U.S. Food and Drug Administration. It targets a rare hereditary disease that causes misshapen proteins to build up in patients’ nerves, tissues and organs, causing loss of sensation, organ failure and even death. Heredity transthyretin amyloidosis, or ATTR, affects about 50,000 people worldwide. This drug will help the subset of those patients who have neurological impairments. Called patisiran, the drug uses specially designed pieces of RNA to silence a mutated gene that, when active in the liver, is responsible for patients’ symptoms. In a recent 18-month clinical trial, patients who received patisiran injections every three weeks showed a slight decrease in neurological symptoms, whereas patients on the placebo worsened overall. It’s not a cure — people still have the genetic mutation — but the treatment prevents the disease from progressing. This approval is “just the beginning,” says Craig Mello of the University of Massachusetts Medical School in Worcester, who co-discovered the process of RNA interference in roundworms (SN: 10/7/06, p. 229). Many more drugs using the same approach, for diseases ranging from hemophilia to HIV, are winding through clinical trials. |© Society for Science & the Public 2000 - 2018

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 25316 - Posted: 08.11.2018

Diana Kwon Bruce Baker, a geneticist who studied gene-behavior interactions in Drosophila melanogaster, died on July 1. He was 72 years old. “Bruce had enormous respect for the details of science, not only the science in his own lab but also that of his peers,” Deborah Andrew, a biologist at Johns Hopkins and one of Baker’s former graduate students, writes in an obituary posted by the Genetics Society of America. Baker was born in Swannanoa, North Carolina in 1945. After completing his undergraduate studies at Reed College in 1966 and receiving a PhD from the University of Washington in 1971, Baker joined the faculty at the University of California, San Diego. In 1986, he became a professor at Stanford University, where he remained for more than two decades before moving to the Howard Hughes Medical Institute’s Janelia Research Campus in 2008. Over the course of his career, Baker published more than 150 papers, primarily focused on the cellular and genetic mechanisms that determine the development of sex-specific characteristics in fruit flies. He also investigated dosage compensation, the strategies used by fruit flies to deal with having one X chromosome instead of two. Among Baker’s scientific contributions is the discovery that the gene encoding the transcription factor Fruitless plays a key role in male-specific courtship behaviors. Studies led by Baker and his colleague, neurobiologist Barry Dickson, revealed that Fruitless (fru) influenced male flies’ attraction to females and, when expressed in females, led them to court other female flies. © 1986 - 2018 The Scientist.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 8: Hormones and Sex
Link ID: 25276 - Posted: 08.01.2018

Carl Zimmer In the largest genetics study ever published in a scientific journal, an international team of scientists on Monday identified more than a thousand variations in human genes that influence how long people stay in school. Educational attainment has attracted great interest from researchers in recent years, because it is linked to many other aspects of people’s lives, including their income as adults, overall health and even life span. The newly discovered gene variants account for just a fraction of the differences in education observed between groups of people. Environmental influences, which may include family wealth or parental education, together play a bigger role. Still, scientists have long known that genetic makeup explains some of the differences in time spent in school. Their hope is that the data can be used to gain a better understanding of what educators must do to keep children in school longer. With a fuller understanding of the influences exerted by genes, scientists think they will be able to better measure what happens when they try to improve a child’s learning environment. The new study, published in the journal Nature Genetics, finds that many of the genetic variations implicated in educational attainment are involved in how neurons communicate in the brain. A striking number are involved in relaying signals out of neurons and into neighboring ones through connections called synapses. The findings are based on genetic sequencing of more than 1.1 million people. But the subjects were all white people of European descent. In order to maximize the odds of discovering genetic links, the scientists say they needed a very large, homogeneous sample. © 2018 The New York Times Company

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 4: Development of the Brain
Link ID: 25244 - Posted: 07.24.2018

By Mark Fischetti The Same Genes May Underlie Different Psychiatric Disorders Schizophrenia brain. 3-D magnetic resonance image (MRI) of the brain of a schizophrenic patient showing structural changes. Credit: Nancy C. Andreasen Getty Images People who have autism, schizophrenia and bipolar disorder may have different challenges, but the ailments might arise from a common set of genes. Researchers compared genetic analyses of 700 human brains from deceased individuals who had one of those three disorders, major depression or alcoholism (columns) with brains of individuals who had none of the conditions. They examined 13 groups of genes thought to function together (rows). The scientists found that five groups had a pattern of overactivity or underactivity across at least three of the five conditions (blue and gray panels). Bipolar disorder, for example, was more similar to schizophrenia than to major depression even though clinicians may link bipolar disorder and depression, based on their symptoms. These insights could possibly reveal new treatments, says neurogeneticist Daniel Geschwind of the University of California, Los Angeles, one of the investigators. He adds that one path to that result, which has not yet been tested, could be to “put the different groups of genes in lab dishes and see which drugs reverse any overexpression or underexpression of the genes.” © 2018 Scientific American

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 25214 - Posted: 07.17.2018

By Ann Gibbons Being smart is a double-edged sword. Intelligent people appear to live longer, but many of the genes behind brilliance can also lead to autism, anxiety, and depression, according to two new massive genetic studies. The work also is one of the first to identify the specific cell types and genetic pathways tied to intelligence and mental health, potentially paving the way for new ways to improve education, or therapies to treat neurotic behavior. The studies provide some of the first “hard evidence of the many genes and pathways” that work together in complex ways to build smart brains and keep them in balance, says geneticist Peter Visscher of the Queensland Brain Institute at The University of Queensland in Brisbane, Australia, who was not involved in the work. Researchers have long known that people often inherit intelligence and some personality disorders from their parents. (Environmental factors such as education and stress also profoundly shape intelligence and mental health.) But geneticists have had trouble identifying more than a handful of genes associated with intelligence. Last year, researchers used new statistical methods that can detect strong associations between genes and specific traits to analyze health and genetic records in huge data sets. This led to the discovery of 52 genes linked to intelligence in 80,000 people. © 2018 American Association for the Advancement of Science

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 25144 - Posted: 06.26.2018

Cassandra Willyard One of the earliest attempts to estimate the number of genes in the human genome involved tipsy geneticists, a bar in Cold Spring Harbor, New York, and pure guesswork. That was in 2000, when a draft human genome sequence was still in the works; geneticists were running a sweepstake on how many genes humans have, and wagers ranged from tens of thousands to hundreds of thousands. Almost two decades later, scientists armed with real data still can’t agree on the number — a knowledge gap that they say hampers efforts to spot disease-related mutations. The latest attempt to plug that gap uses data from hundreds of human tissue samples and was posted on the BioRxiv preprint server on 29 May1. It includes almost 5,000 genes that haven’t previously been spotted — among them nearly 1,200 that carry instructions for making proteins. And the overall tally of more than 21,000 protein-coding genes is a substantial jump from previous estimates, which put the figure at around 20,000. But many geneticists aren’t yet convinced that all the newly proposed genes will stand up to close scrutiny. Their criticisms underscore just how difficult it is to identify new genes, or even define what a gene is. “People have been working hard at this for 20 years, and we still don’t have the answer,” says Steven Salzberg, a computational biologist at Johns Hopkins University in Baltimore, Maryland, whose team produced the latest count. © 2018 Macmillan Publishers Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 25106 - Posted: 06.20.2018

/ By Michael Schulson Late last month, Senate Minority Leader Chuck Schumer took a break from the tax bill debate to talk with reporters about genetics. It takes just a few minutes to put some spit into a vial, but that little bit of spit can yield volumes of deeply intimate data. In a press conference, the New York senator criticized how direct-to-consumer genetic testing companies — outfits like 23andMe and AncestryDNA — discuss and handle users’ genetic information. “What those companies can do with all that data — your most sensitive and deepest info, your genetics — is not clear, and in some cases not fair and not right,” said Schumer. Schumer called on the Federal Trade Commission to launch an investigation into genetic testing companies’ privacy and disclosure practices, though the commercial and regulatory tides seem — at least for now — to be going in the other direction. Discounted prices for 23andMe dropped below $50 earlier this year, and sales of AncestryDNA kits are breaking records: In the weekend after Thanksgiving, the company said it had sold around 1.5 million genetic tests. That’s more units than 23andMe sold in its first eight years on the market. Last spring, for the first time, the Food and Drug Administration approved an over-the-counter test that tells consumers their genetic risk for a variety of conditions, from Parkinson’s and Alzheimer’s to Celiac disease and numerous blood diseases. And a new FDA policy announced at the beginning of November is likely to allow a wave of new, health-oriented genetic screening products to enter the market. Copyright 2017 Undark

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 24466 - Posted: 12.29.2017

By Corinna Hartmann, Andreas Jahn Medical historians have recently published accounts that show neurologists were indeed complicit with the Nazis—and became victims if they were classified as “non-Aryan. Heiner Fangerau, who teaches the history and ethics of medicine at University Hospital Düsseldorf—along with colleagues Michael Martin at the Heinrich Heine University of Düsseldorf and Axel Karenberg from the University of Cologne—undertook extensive research on neurologists during the Third Reich for the German Society of Neurology. Fangerau discussed new findings with Corinna Hartmann and Andreas Jahn of Gehirn&Geist, the psychology and neuroscience specialty publication of Spektrum der Wissenschaft, and the German sister publication of Scientific American. An edited transcript of the interview follows. Professor Fangerau, your research project examines the role played by neurologists during the Nazi period. Why is this only happening 70 years after the fact? Advertisement There were several different phases in which people dealt with National Socialism after World War II. Immediately after 1945 the Allies pursued a policy of denazification. After that German society as a whole attempted to suppress its dark past. Many members of the next generation, however, found it impossible to close their eyes: Students in the 1968 movement were angry that their parents were unwilling to deal openly with the “Third Reich.” The medical specialties took even longer to begin working through the past. As a result, their reappraisal of the crimes committed began only in the 1980s. Part of the reason why historical research into neurology has only been conducted systematically over the past several years is that neurology and psychiatry were forced into the same disciplinary framework in 1935. Before then neurology had begun to separate from psychiatry. The basic idea was to leave psychological phenomena that are difficult to understand to the psychiatrists and to concentrate on disorders that are anatomically demonstrable. The National Socialists nullified this effort. They believed that they could control these medical specialties more effectively if they brought them together in the Society of German Neurologists and Psychiatrists, which was dominated by psychiatrists committed to the ideology of racial hygiene. The chairman of the society was Ernst Rüdin, a psychiatrist. As a result, neurology has come to be viewed as less implicated. Historical research conducted since the late 1980s, however, paints a very different picture. © 2017 Scientific American

Related chapters from BN: Chapter 1: Introduction: Scope and Outlook; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 20: ; Chapter 4: Development of the Brain
Link ID: 24238 - Posted: 10.25.2017

By GINA KOLATA For the first time, doctors have used gene therapy to stave off a fatal degenerative brain disease, an achievement that some experts had thought impossible. The key to making the therapy work? One of medicine’s greatest villains: HIV. The patients were children who had inherited a mutated gene causing a rare disorder, adrenoleukodystrophy, or ALD. Nerve cells in the brain die, and in a few short years, children lose the ability to walk or talk. They become unable to eat without a feeding tube, to see, hear or think. They usually die within five years of diagnosis. The disease strikes about one in 20,000 boys; symptoms first occur at an average age of 7. The only treatment is a bone-marrow transplant — if a compatible donor can be found — or a transplant with cord blood, if it was saved at birth. But such transplants are an onerous and dangerous therapy, with a mortality rate as high as 20 percent. Some who survive are left with lifelong disabilities. Now a new study, published online in the New England Journal of Medicine, indicates that gene therapy can hold off ALD without side effects, but only if it is begun when the only signs of deterioration are changes in brain scans. The study involved 17 boys (the disease strikes males almost exclusively), ages 4 to 13. All got gene therapy. Two years later, 15 were functioning normally without obvious symptoms. “To me, it seems to be working,” said Dr. Jim Wilson, director of the gene therapy program at the University of Pennsylvania’s Perelman School of Medicine, who was not involved in the new study. © 2017 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 24157 - Posted: 10.06.2017

Tina Hesman Saey Some Pakistani people are real knockouts, a new DNA study finds. Knockouts in this sense doesn’t refer to boxing or a stunning appearance, but to natural mutations that inactivate, or “knock out” certain genes. The study suggests that human knockouts could prove valuable evidence for understanding how genes work and for developing drugs. Among 10,503 adults participating in a heart disease study in Pakistan, 1,843 people have at least one gene of which both copies have been knocked out, researchers report online April 12 in Nature. Researchers also drew blood from many of the participants and used medical records to study more than 200 traits, such as heart rate, blood pressure and blood levels of sugar, cholesterol, hormones or other substances. Studying how the knockout mutations affect those traits and health could point to genes that are potentially safe and effective targets for new drugs. Combining genetic data with medical information will provide “a rich dataset for many applications,” says Robert Plenge, a human geneticist formerly with the pharmaceutical company Merck. Scientists have traditionally learned about genes’ roles by deleting the genes from mice and then cataloging abnormalities in how those mice developed and behaved. Such animal research will always be needed, but studies of people naturally lacking certain genes “will change the nature of the scientific investigation of the genetic basis of human disease,” Plenge wrote in a commentary in the same issue of Nature. Often, a person will inherit a broken copy of a gene from one parent and a healthy copy from the other. But 39 percent of the people in this study had parents who were closely related — often first cousins — increasing the odds of inheriting two mutant copies of a gene. Of this study’s 1,843 participants, 1,504 had both copies of a single gene knocked out. The rest had more than one gene knocked out, including one person in whom six genes were predicted to be completely nonfunctional. |© Society for Science & the Public 2000 - 2017.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 23487 - Posted: 04.13.2017

by Adriana Heguy, molecular biologist and genomics researcher: Interestingly, tongue-curling ability is not solely genetic, and the genetic component may be very small. Monozygotic (identical) twins are not always concordant for tongue-curling ability, so if there is a genetic component, it’s clearly not Mendelian. In other words, it’s not a trait coded by one single gene, and it’s clearly influenced by the environment—in this case, practice. But for some reason this is one of the “myths” about genetics that gets spread around in high school, where it is used as an example of a simple Mendelian trait with a simple dominant-recessive nature. It’s hard to comment on the evolutionary purpose of an ability so heavily influenced by the environment, and not obviously useful. There are many traits for which we do not have the faintest idea why they exist or what purpose they serve. In the case of tongue-curling, it’s possible that it’s a case of fine motor control of the tongue. We need to be able to move our tongues to not bite them when we eat, for example, and for swirling food around. For unknown reasons, some individuals are better than others at controlling tongue movement. And since the ability can be acquired by practicing (though not everybody apparently succeeds), it does seem likely that it is indeed a question of motor control. Most people are able to do it. It’s quite common. But it could be that evolution had nothing to do with it. Or it could be a spandrel; in other words, a side effect of evolution. Maybe the evolution of dexterity or finer motor control of other muscles resulted in tongue “dexterity.” It’s possible that it is an atavism, something that increased tongue muscle control was once useful for tasting or eating certain kinds of foods millions of years ago, and it has not disappeared because the developmental program for fine muscle control is still there.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 22415 - Posted: 07.09.2016

By Sarah Kaplan You probably wouldn't be surprised if a scientist told you that your genes influence when you hit puberty, how tall you are, what your BMI will be and whether you're likely to develop male pattern baldness. But what if he said that the same gene could hold sway over all four things? That finding comes from a study published Monday in the journal Nature Genetics. Using data from dozens of genome-wide association studies (big scans of complete sets of DNA from many thousands of people), researchers at the New York Genome Center and the genetic analysis company 23andMe found examples of single "multitasking" genes that influence diverse and sometimes seemingly disparate traits. The scientists say that the links they uncovered could help researchers understand how certain genes work, and figure out better ways of treating some of the health problems they might control. "Most studies tend to go one disease at a time," said Joseph Pickrell, a professor at Columbia University and the New York Genome Center's lead investigator on the project. "But if we can try to make these sorts of connections between what you might think of as unrelated traits ... that gives us another angle of attack to understand the connections between these different diseases." To start, Pickrell and his team sought out genome-wide association studies (GWAS) identifying particular genetic variants associated with 42 different traits. Many had to do with diseases (for example, studies that linked certain genes to the risk of developing Alzheimer's or type 2 diabetes) and other personal health traits (body mass index, blood type, cholesterol levels).

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 22225 - Posted: 05.18.2016

Erika Check Hayden The largest-ever genetics study in the social sciences has turned up dozens of DNA markers that are linked to the number of years of formal education an individual completes. The work, reported this week in Nature, analysed genetic material from around 300,000 people. “This is good news,” says Stephen Hsu, a theoretical physicist at Michigan State University in East Lansing, who studies the genetics of intelligence. “It shows that if you have enough statistical power you can find genetic variants that are associated with cognitive ability.” Yet the study’s authors estimate that the 74 genetic markers they uncovered comprise just 0.43% of the total genetic contribution to educational achievement (A. Okbay et al. Nature http://dx.doi.org/10.1038/nature17671; 2016). By themselves, the markers cannot predict a person’s performance at school. And because the work examined only people of European ancestry, it is unclear whether the results apply to those with roots in other regions, such as Africa or Asia. The findings have proved divisive. Some researchers hope that the work will aid studies of biology, medicine and social policy, but others say that the emphasis on genetics obscures factors that have a much larger impact on individual attainment, such as health, parenting and quality of schooling. © 2016 Nature Publishing Group

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 4: Development of the Brain
Link ID: 22209 - Posted: 05.12.2016

By David Z. Hambrick Nearly a century after James Truslow Adams coined the phrase, the “American dream” has become a staple of presidential campaign speeches. Kicking off her 2016 campaign, Hillary Clinton told supporters that “we need to do a better job of getting our economy growing again and producing results and renewing the American dream.” Marco Rubio lamented that “too many Americans are starting to doubt” that it is still possible to achieve the American dream, and Ted Cruz asked his supporters to “imagine a legal immigration system that welcomes and celebrates those who come to achieve the American dream.” Donald Trump claimed that “the American dream is dead” and Bernie Sanders quipped that for many “the American dream has become a nightmare.” But the American dream is not just a pie-in-the-sky notion—it’s a scientifically testable proposition. The American dream, Adams wrote, “is not a dream of motor cars and high wages merely, but a dream of social order in which each man and each woman shall be able to attain to the fullest stature of which they are innately capable…regardless of the fortuitous circumstances of birth or position.” In the parlance of behavioral genetics—the scientific study of genetic influences on individual differences in behavior—Adams’ idea was that all Americans should have an equal opportunity to realize their genetic potential. A study just published in Psychological Science by psychologists Elliot Tucker-Drob and Timothy Bates reveals that this version of the American dream is in serious trouble. Tucker-Drob and Bates set out to evaluate evidence for the influence of genetic factors on IQ-type measures (aptitude and achievement) that predict success in school, work, and everyday life. Their specific question was how the contribution of genes to these measures would compare at low versus high levels of socioeconomic status (or SES), and whether the results would differ across countries. The results reveal, ironically, that the American dream is more of a reality for other countries than it is for America: genetic influences on IQ were uniform across levels of SES in Western Europe and Australia, but, in the United States, were much higher for the rich than for the poor. © 2016 Scientific American

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 4: Development of the Brain
Link ID: 22051 - Posted: 03.30.2016

Laura Sanders You can thank your parents for your funny-looking hippocampus. Genes influence the three-dimensional shape of certain brain structures, scientists report in a paper posted online December 1 at bioRxiv.org. Showing a new way that genes help sculpt the brain opens up more ways to explore how the brain develops and operates. Earlier work linked genes to simple measurements of brain structures, such as overall volume or length. The new work goes beyond that by mathematically analyzing complex 3-D shapes and tying those shapes to a particular genetic makeup. A team led by researchers at Massachusetts General Hospital and Harvard Medical School analyzed MRI brain scans and genome data from 1,317 healthy young adults. Particular genetic profiles influenced the 3-D shape of structures including the hippocampus, caudate and cerebellum, the scientists found. In some brains, for instance, genes played a role in making the seahorse-shaped right hippocampus skinnier on the top and wider on the bottom. Genes also influenced whether the tail of the caudate was short or long. Quirks of brain structure shapes might play a role in disorders such as schizophrenia, autism spectrum disorder and bipolar disorder, which are known to be influenced by genes, the authors write. Citations T. Ge et al. Heritability of neuroanatomical shape. bioRxiv.org. Posted December 1, 2015. doi: 10.1101/033407. © Society for Science & the Public 2000 - 2015

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 21692 - Posted: 12.12.2015

Tina Hesman Saey 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. Inoculate endangered amphibians against killer fungi? Yes. Pluck invasive species from environments where they don’t belong? As you wish. 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. A gene drive is a targeted contagion intended to spread within species, forever altering the offspring. Gene drive enthusiasts say these genies could wipe out malaria, saving more than half a million lives each year. Invasive species, herbicide-resistant weeds and pesticide-resistant bugs could be driven out of existence. Animals that carry harmful viruses could be immunized with ease. Scientists have sought the power of gene drives for decades. But only with the emergence of a genetic tool called CRISPR/Cas9 — the bottle opener that unleashed the genie — has gene drive technology offered the prospect of providing a speedy means to end some of the world’s greatest health and ecological scourges. “Everything is possible with CRISPR,” says geneticist Hugo Bellen. “I’m not kidding.” © Society for Science & the Public 2000 - 2015.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 21671 - Posted: 12.03.2015

Ewen Callaway A mysterious group of humans crossed the Bering land bridge from Siberia into the Americas thousands of years ago, genetic analyses reveal. Modern-day signatures of this ‘ghost population’ survive in people who live deep in the Brazilian Amazon, but the two research teams who have made the discovery have different ideas about when and how these migrants reached the Americas1, 2. "This is an unexpected finding," says Jennifer Raff, an anthropological geneticist at the University of Texas at Austin who was not involved in either study. "It’s honestly one of the most exciting results we’ve seen in a while." North and South America were the last continents that humans settled. Previous studies of DNA from modern and ancient Native Americans suggest that the trek was made at least 15,000 years ago (although the timing is not clear-cut) by a single group dubbed the ‘First Americans’, who crossed the Bering land bridge linking Asia and North America. “The simplest hypothesis would be that a single population penetrated the ice sheets and gave rise to most of the Americans,” says David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts. In 2012, his team found evidence for a single founding migration in the genomes from members of 52 Native American groups3. So Reich was flabbergasted when a colleague called Pontus Skoglund mentioned during a conference last year that he had found signs of a second ancient migration to the Americas lurking in the DNA of contemporary Native Amazonians. Reich wasted no time in verifying the discovery. “During the session afterward, he passed his laptop over the crowd, and he had corroborated the results,” says Skoglund, who is now a researcher in Reich’s lab. © 2015 Nature Publishing Group

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 21201 - Posted: 07.22.2015

By Tina Hesman Saey Combatants in the age-old battle of nature versus nurture may finally be able to lay down their arms. On average, both nature and nurture contribute roughly equally to determining human traits. Researchers compiled data from half a century’s worth of studies on more than 14 million pairs of twins. The researchers measured heritability — the amount of variation in a characteristic that can be attributed to genes — for a wide variety of human traits including blood pressure, the structure of the eyeball and mental or behavioral disorders. All traits are heritable to some degree, the researchers report May 18 in Nature Genetics. Traits overall had an average heritability of 49 percent, meaning it’s a draw between genes and environment. Individual traits can be more strongly influenced by one or the other. 100% Fraction of human traits with a genetic component 49% Fraction of variability in human traits determined by genes T.J.C. Polderman et al. Meta-analysis of the heritability of human traits based on fifty years of twin studies. Nature Genetics. Published online May 18, 2015. doi:10.1038/ng.3285. © Society for Science & the Public 2000 - 2015.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 20985 - Posted: 05.27.2015