By Emily Anthes We take it for granted that certain aspects of our social behavior—whether we chat easily with strangers at a party, for instance, or prefer to be a wallflower—are influenced by genetics. But now researchers at the University of California, San Diego, and Harvard University have shown that genes have a much broader sway, affecting the kinds of social networks people form and the positions they occupy in them. James Fowler, a political scientist at U.C.S.D., and his colleagues studied the social networks of 1,110 adolescent fraternal and identical twins. They found that three aspects of the twins’ social networks appeared to be shaped by genetics. How many times each teen was named by others as a friend and how likely each youth’s friends were to know one another were both approximately 50 percent related to genetic factors. Whether a teen was located at the center of a network or toward the edge was about 30 percent genetic. “We have innate characteristics that give us a tendency to gravitate toward one part of a network,” Fowler explains. “We vary in the tendency with which we’ll attract people as friends, and we vary in our tendency to introduce our friends to one another.” The genetic foundation uncovered in the study, he posits, is probably a broad combination of genes that are mostly linked to personality traits such as humor, generosity or extroversion. © 1996-2009 Scientific American Inc.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 11: Emotions, Aggression, and Stress
Link ID: 13037 - Posted: 06.24.2010

By Tina Hesman Saey Whether you like it or not, you’re a little different. If it makes you feel any better, so is everybody else. In fact, everybody is far more different than anybody had imagined. Scientists are only beginning to discover just how different humans are from each other at the genetic level and what those personal genetic attributes mean for health, history and the human evolutionary future. It’s true that people are 99.9 percent alike, if only minor spelling variations in the genetic instruction book are taken into account. In each person, about one in every 1,000 DNA bases — the chemical letters of the genetic alphabet — differs from the generic human construction and operating manual. So, on average, one person will differ from another at about 3 million of the 3 billion letters in the human genome. Researchers have recently mapped many of these single letter variations, called single 
nucleotide polymorphisms or SNPs, looking for variants that might play a role in complex diseases such as heart disease, diabetes and high blood pressure (SN: 6/21/08, p. 20). So far, SNPs have been associated with many diseases, but SNPs can also be protective. And those little spelling differences may contain information about a person’s geographic ancestry — just as whether people write color or colour is a clue about whether they hail from the United States or Great Britain. © Society for Science & the Public 2000 - 2009

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: 12744 - Posted: 06.24.2010

By Tina Hesman Saey Tattoos on the skin can say a lot about person. On a deeper level, chemical tattoos on a person’s DNA are just as distinctive and individual — and say far more about a person’s life history. A pair of reports published online January 18 in Nature Genetics show just how important one type of DNA tattoo, called methylation, can be. Researchers at Johns Hopkins University report the unexpected finding that most DNA methylation — a chemical alteration that turns off genes — occurs most often near, but not precisely within, the DNA regions on which scientists have typically focused their studies. The other report, from researchers at the Universityof Toronto and collaborators, suggests that identical twins owe their similarity not only to having the same genetic make-up, but also to certain methylation patterns established in the fertilized egg. Methylation is just one of many epigenetic signals — chemical changes to DNA and its associated proteins — that modify gene activity without altering the genetic information in the genes. Methylation and other epigenetic signals help guide stem cells as they develop into other type of cells. Scientists have long suspected that mishandling methylation and other epigenetic flags could lead to cancer. The Johns Hopkins group has now shown that DNA methylation is more common at what they call “CpG island shores” instead of at the CpG islands that most researchers have been studying. CpG islands are short stretches of DNA rich in the bases cytosine and guanine, also known as C and G in the genetic alphabet. (Adenine (A) and thymine (T) are the other DNA bases.) CpG islands are located near the start site of genes and help control a gene’s activity. Planting a chemical flag called a methyl group on an island declares the gene off-limits, blocking activity. © Society for Science & the Public 2000 - 2009

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: 12457 - Posted: 06.24.2010

By Victoria Stern Spinal cord injuries and disorders afflict millions worldwide, from disabled veterans to people with neurodegenerative disorders such as Lou Gehrig’s disease, yet there is currently no way to repair a damaged spine. Geneticists at the Allen Institute for Brain Science in Seattle are hoping to change that by developing the first genetic encyclopedia of the spinal cord. The Allen Spinal Cord Atlas, which will be available online for free in early 2009, will map out which genes are active in which locations along the spine in mice, which share 90 percent of their genetic material with humans. Researchers are looking forward to using the new tool, based on the success of the Allen Institute’s 2006 Brain Atlas. That genetic map led to key insights, such as the link between glioblastoma, the deadliest type of brain tumor, and a gene called BEX1. Gregory Foltz of Swedish Medical Center in Seattle saw that BEX1 was turned off in the brains of his tumor patients, and using the Brain Atlas, he confirmed that the gene is usually active in healthy brains, as reported in Cancer Research in 2006. Foltz realized that when BEX1 is inhibited, cells grow uncontrollably and can form tumors—and researchers hope to develop treatments that target the malfunctioning gene. © 1996-2008 Scientific American Inc.

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: 12122 - Posted: 06.24.2010

By Karen Schrock Have you ever emerged from a matinee movie, squinted into the sudden burst of sunlight and sneezed uncontrollably? Up to a third of the population will answer this question with an emphatic "Yes!" (whereas nearly everyone else scratches their head in confusion). Sneezing as the result of being exposed to a bright light—known as the photic sneeze reflex—is a genetic quirk that is still unexplained by science, even though it has intrigued some of history's greatest minds. Aristotle mused about why one sneezes more after looking at the sun in The Book of Problems: "Why does the heat of the sun provoke sneezing?" He surmised that the heat of the sun on the nose was probably responsible. Some 2 ,000 years later, in the early 17th century, English philosopher Francis Bacon neatly refuted that idea by stepping into the sun with his eyes closed—the heat was still there, but the sneeze was not (a compact demonstration of the fledgling scientific method). Bacon's best guess was that the sun's light made the eyes water, and then that moisture ("braine humour," literally) seeped into and irritated the nose. Humours aside, Bacon's moisture hypothesis seemed quite reasonable until our modern understanding of physiology made it clear that the sneeze happens too quickly after light exposure to be the result of the comparatively sluggish tear ducts. So neurology steps in: Most experts now agree that crossed wires in the brain are probably responsible for the photic sneeze reflex. © 1996-2007 Scientific American Inc.

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: 11198 - Posted: 06.24.2010

By RICHARD E. NISBETT JAMES WATSON, the 1962 Nobel laureate, recently asserted that he was “inherently gloomy about the prospect of Africa” and its citizens because “all our social policies are based on the fact that their intelligence is the same as ours — whereas all the testing says not really.” Dr. Watson’s remarks created a huge stir because they implied that blacks were genetically inferior to whites, and the controversy resulted in his resignation as chancellor of Cold Spring Harbor Laboratory. But was he right? Is there a genetic difference between blacks and whites that condemns blacks in perpetuity to be less intelligent? The first notable public airing of the scientific question came in a 1969 article in The Harvard Educational Review by Arthur Jensen, a psychologist at the University of California, Berkeley. Dr. Jensen maintained that a 15-point difference in I.Q. between blacks and whites was mostly due to a genetic difference between the races that could never be erased. But his argument gave a misleading account of the evidence. And others who later made the same argument — Richard Herrnstein and Charles Murray in “The Bell Curve,” in 1994, for example, and just recently, William Saletan in a series of articles on Slate — have made the same mistake. In fact, the evidence heavily favors the view that race differences in I.Q. are environmental in origin, not genetic. Copyright 2007 The New York Times Company

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: 11070 - Posted: 06.24.2010

Ewen Callaway Spit might have helped human evolution by enabling our ancestors to harvest more energy from starch than their primate cousins. Compared with chimpanzees, humans boast many more copies of the gene that makes salivary amylase — a saliva enzyme that breaks down starch into digestible sugars. And carbohydrate-loving societies carry more copies of the gene than those that follow low-carbohydrate diets, claims a new study in Nature Genetics1. This strongly implies that people have adapted to their local environment. "High starch foods and a high starch diet have been an important evolutionary force for humans," says George Perry, an anthropologist at Arizona State University in Tempe, who led the new analysis. The change could possibly have supported the growth in hominin brains that occurred some two million years ago, says Nate Dominy, an anthropologist at the University of California in Santa Cruz involved in the study. "Our diet must have had some shift to feed that brain," says Dominy, who thinks root vegetables like African tubers allowed large-brained humans to flourish. Starch, which helps to make a baked potato mushy, is an important source of food for modern humans. But without amylase in the saliva, man can make little use of such complex carbohydrates - enzymes elsewhere in the body are not as good at breaking the compounds down. ©2007 Nature Publishing Group

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 0: ; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 10704 - Posted: 06.24.2010

RICHLAND, Wash. — The Allen Brain Atlas, a genome-wide map of the mouse brain on the Internet, has been hailed as “Google of the brain.” The atlas now has a companion or the brain’s working molecules, a sort of pop-up book of the proteins, or proteome map, that those genes express. The protein map is “the first to apply quantitative proteomics to imaging,” said Richard D. Smith, Battelle Fellow at the Department of Energy’s Pacific Northwest National Laboratory, who led the mapping effort with Desmond Smith of UCLA’s David Geffen School of Medicine. “Proteins are the lead actors, the most important part of the picture,” PNNL’s Smith said. “They are the molecules that do the work of the cells.” Fine-tuning such proteome maps will enable comparisons of healthy brains with others whose protein portraits look different. Contrasts in location and abundance of proteins may display the earliest detectable stages of Alzheimer’s, Parkinson’s and other neurological diseases. They hope such diseases might be curbed if caught and treated early enough. The National Institutes of Health-funded study, performed at DOE’s Environmental Molecular Sciences Laboratory on PNNL’s campus, is published in the advance online edition of Genome Research and featured in current Nature online Neuroscience Gateway (http://www.brainatlas.org). PNNL staff scientists Vladislav A. Petyuk, Wei-Jun Qian and UCLA’s Mark Chin are co-lead authors.

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: 9979 - Posted: 06.24.2010

ANN ARBOR, Mich.—What makes a bee a he or a she? Three years ago, scientists pinpointed a gene called csd that determines gender in honey bees, and now a research team led by University of Michigan evolutionary biologist Jianzhi "George" Zhang has unraveled details of how the gene evolved. The new insights could prove useful in designing strategies for breeding honey bees, which are major pollinators of economically important crops—and notoriously tricky to breed. The findings of Zhang and collaborators appear in a special issue of Genome Research devoted to the biology of the honey bee. The issue will be published online and in print Oct. 26, coinciding with the publication of the honey bee genome sequence in the journal Nature. Scientists have long known that in bees—as well as wasps, ants, ticks, mites and some 20 percent of all animals—unfertilized eggs develop into males, while females typically result from fertilized eggs. But that's not the whole story, and the discovery in 2003 of csd (the complementary sex determination gene) helped fill in the blanks. The gene has many versions, or alleles. Males inherit a single copy of the gene; bees that inherit two copies, each a different version, become female. Bees that have the misfortune of inheriting two identical copies of csd develop into sterile males but are quickly eaten at the larval stage by female worker bees. © 2005 The Regents of the University of Michigan

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 9537 - Posted: 06.24.2010

Combining data from years of laboratory work with the power of bioinformatics, researchers have created a map that helps explain how the brain generates the assortment of specialized proteins it needs to process information. The map, created by Howard Hughes Medical Institute (HHMI) investigator Robert B. Darnell and colleagues at The Rockefeller University, describes the rules that govern the activity of a protein called Nova. By regulating a process called alternative splicing, Nova helps brain cells produce a set of proteins involved in communication at synapses, or the junctions between neurons. The new study, published October 25, 2006, in an advance online publication of the journal Nature, furthers understanding of a process that, when not properly regulated, can lead to cancer, neurologic diseases, or other ailments. Limited to the same set of genes that encode the instructions for all cells in the body, brain cells rely heavily on alternative splicing to generate the protein diversity they need to function properly. The process, at work in all cells in organisms ranging from fruit flies to humans, chooses bits and pieces of an RNA copy of a gene, piecing segments together to form a blueprint for the precise protein that is needed. Using alternative splicing to assemble different patterns, a single gene can give rise to multiple — sometimes thousands — of proteins. Scientific interest in alternative splicing has grown in recent years, in part because the phenomenon helps explain how humans can be so complex despite having a genome that is surprisingly similar in size to that of simpler organisms, like flies and worms. © 2006 Howard Hughes Medical Institute.

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: 9533 - Posted: 06.24.2010

— A map of the mouse brain down to details of individual cells has been completed, the first project of an institute funded by Microsoft Corp. co-founder Paul G. Allen, it was announced Tuesday. The new Allen Brain Atlas is being made available online without cost to neuroscientists studying brain circuits and chemistry, a potential boon to cancer and other disease research because of similarities between the brains of mice and human beings, according to a statement issued by the Allen Institute of Brain Science. "We want people to use this and make discoveries," Dr. Allan Jones, the institute's chief scientific officer, told The Seattle Post-Intelligencer. A formal announcement was planned in Washington, D.C., with Allen and Sens. Patty Murray, D-Wash, and Ted Stevens, R-Alaska. Because more than 90 percent of the same genes are found in mice and humans, the mouse brain map can be compared with genetic findings related to human neurological disorders. Moreover, the mapping project has shown that 80 percent of the body's genes are switched on in the brain, compared with 60 percent to 70 percent in previous scientific estimates, Jones said. © 2006 Discovery Communications Inc.

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: 9391 - Posted: 06.24.2010

Jennifer Viegas, Discovery News — Genes shape our health and appearance more than they shape our personality, suggests a new study of thousands of people in a genetically isolated part of the world. According to the study, published in the August issue of PLoS Genetics, genetics account for roughly 51 percent of a person’s height, weight and overall body shape, 25 percent of cardiovascular function, and about 40 percent of certain blood characteristics, such as sugar and cholesterol levels. But genes only account for about 19 percent of many documented personality traits, such as neuroticism, extraversion, agreeableness and conscientiousness. "My personal view is that we have evolved to have very diverse personalities and that, compared to other traits, personality may be much less deterministic than other human characteristics," said Gonçalo Abecasis, one of the study’s authors. "My view is that both genes and environment will play smaller roles than random factors." Abecasis, a scientist at the Center for Statistical Genetics at the University of Michigan, and his colleagues examined 6,148 people from the Mediterranean island of Sardinia, where many residents are related. Roughly 95 percent of all test subjects’ grandparents were Sardinian, and the test group included 5,000 pairs of siblings. © 2006 Discovery Communications Inc.

Related chapters from BN: Chapter 15: Emotions, Aggression, and Stress; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 4: Development of the Brain
Link ID: 9294 - Posted: 06.24.2010

By AMY HARMON Jason Dallas used to think of his daredevil streak — a love of backcountry skiing, mountain bikes and fast vehicles — as "a personality thing." Jason Dallas of Seattle says he believes he is genetically predisposed toward risky behavior like backcountry skiing and mountain biking. Then he heard that scientists at the Fred Hutchinson Cancer Research Center in Seattle had linked risk-taking behavior in mice to a gene. Those without it pranced unprotected along a steel beam instead of huddling in safety like the other mice. Now Mr. Dallas, a chef in Seattle, is convinced he has a genetic predisposition for risk-taking, a conclusion the researchers say is not unwarranted, since they believe similar variations in human genes can explain why people perceive danger differently. "It's in your blood," Mr. Dallas said. "You hear people say that kind of thing, but now you know it really is." A growing understanding of human genetics is prompting fresh consideration of how much control people have over who they are and how they act. The recent discoveries include genes that seem to influence whether an individual is fat, has a gift for dance or will be addicted to cigarettes. Pronouncements about the power of genes seem to be in the news almost daily, and are changing the way some Americans feel about themselves, their flaws and their talents, as well as the decisions they make. Copyright 2006 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: 9038 - Posted: 06.24.2010

By JENNIFER MEDINA ALBANY, — A California neuroscientist and biologist whose research of fruit flies found genetic links to human behavior was awarded the $500,000 Albany Medical Center Prize in Medicine and Biomedical Research, the country's largest award in the field. The winner, Dr. Seymour Benzer, a researcher at the California Institute of Technology, began his pioneering research in neurological sciences in the 1960's, laying a foundation for generations of researchers who came after him, the judges said in their announcement on Friday. Dr. Benzer, now 84, is known for challenging the widespread belief that human behavior was shaped largely by outside forces. "Behavior can be dissected by manipulation," Dr. Benzer said at news conference at an Albany hotel. "Take your choice, you can start with genetic structure and make enormous differences in the environment." He said he became intrigued with the topic when his second daughter was born and he noticed remarkable differences from his first daughter. "I wondered, 'Are my wife and I doing things that differently?' " Dr. Benzer said. Copyright 2006 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: 8850 - Posted: 06.24.2010

Two risk factors that place males at greater risk for heart disease than women appear to be influenced by genes on the X chromosome, report researchers at the NIH and the University of Texas Southwestern Medical School. The finding appears in a Research Letter in the Journal of the American Medical Association. In a separate Research Letter, the researchers at the NIH and at Thomas Jefferson University in Philadelphia also report that women who lack functioning ovaries — either because of a hereditary condition or due to an illness — are more likely than are other women to experience shyness and anxiety in social situations. In the first report, researchers studied women with Turner syndrome, a hereditary condition in which women are missing all or part of one X chromosome, explained the senior author of both reports, Carolyn Bondy, Chief of the Developmental Endocrinology Branch at NIH’s National Institute of Child Health and Human Development. The researchers tested whether the women had inherited their single normal X chromosome from their mothers or from their fathers. Women normally inherit one of their two X chromosomes from their mother and one from their father. Men normally inherit a single X chromosome from their mothers. The researchers also measured the women’s body fat distribution patterns and their cholesterol and triglyceride levels. Dr. Bondy explained that men have a greater tendency than do women to accumulate fat within their abdomens, while women tend to accumulate fat around their hips, buttocks, and thighs. Proportionally higher abdominal fat distribution is associated with cholesterol levels that increase the chances of cardiovascular disease.

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 8: Hormones and Sex
Link ID: 8685 - Posted: 06.24.2010

BAR HARBOR, Maine - When it comes to the price of mice, you pay extra for defects. A mouse with arthritis runs close to $200; two pairs of epileptic mice can cost 10 times that. You want three blind mice? That’ll run you about $250. And for your own custom mouse, with the genetic modification of your choosing, expect to pay as much as $100,000. Always a mainstay of scientific research, mice have become a critical tool in the quest for new drugs and medical treatments because their genes are remarkably similar to a person’s. With proper manipulation — either by man or nature — a set of mouse genes can produce an animal with just about any human ailment, or a reasonable facsimile of it. Strains of mice that succumb to Alzheimer’s disease, obesity, diabetes, cancer and countless other conditions are being used to study both the illnesses themselves and potential treatments. As many as 25 million mice are now used in experiments each year. Where do they come from? Where else? Mouse farms. © 2006 MSNBC.com © 2006 Microsoft

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: 8622 - Posted: 06.24.2010

Review by WILLIAM SALETAN JUDITH RICH HARRIS calls "No Two Alike" a "scientific detective story." The mystery is why people — even identical twins who grow up in the same home with the same genes — end up with different personalities. The detective is Harris herself, a crotchety amateur, housebound because of an illness, who takes on the academic establishment armed only with a sharp mind and an Internet connection. Harris the author scrupulously follows clues; Harris the protagonist drives the story forward through force of character, arriving at a theory of personality that could be said to describe herself. Eight years ago, Harris's book "The Nurture Assumption" set academic psychology on fire by attacking the notion that parenting styles shape children. Scholars, irked by this upstart former textbook writer and grad-school reject, scorned her argument. In her new book, Harris tries to embarrass her critics while synthesizing her work into a theory of personality. "No Two Alike" is two books: a display of human weakness, and a display of scientific courage and imagination. Every detective has a favorite method. Harris's is behavioral genetics, which attempts to tease out the genetic bases of behavior. To sort genetic from environmental factors, you study people with the same genes but different environments: identical twins raised apart. Or you study people with different genes but the same environment: adoptive siblings raised together. Copyright 2006 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 0: ; Chapter 4: Development of the Brain
Link ID: 8614 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Professional dancers are born with at least two special genes that give them a leg up on the rest of us, according to a new study. Recent research also has suggested that intelligence, athletic ability and musical talent are linked to our genes and brain hard-wiring. With dancing added to the list, the evidence indicates that certain individuals are born with a predisposition to specific behaviors and talents, and that at least some of these qualities may represent evolved attributes. "I think that dancing is an evolved trait," said Richard Ebstein, who led the recent study, published in a recent Public Library of Science Genetics journal. "Animals have courtship dances and I think that human dancing represents the further development of a very ancient animal trait." Ebstein, a psychology professor at Hebrew University's Scheinfeld Center for Genetic Studies, said, "Also the fact that dancing is universal and existed in all human societies, even those communities of man separated geographically by tens of thousands of years (native Australians, native Americans, Africans, Eurasians) attests to the very early origin of dance in our evolution as a species." © 2006 Discovery Communications Inc.

Related chapters from BN: Chapter 11: Motor Control and Plasticity; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 8: Hormones and Sex
Link ID: 8563 - Posted: 06.24.2010

Gerontologist Stephen Kritchevsky says differences in our genes may explain why some of us reap the benefits of exercise more than others — especially as we age. This may offer new opportunities to explore treatments to help older adults maintain their mobility. "Even if you exercise, it doesn't guarantee that you will maintain function," says Kritchevsky, from Wake Forest University Baptist Medical Center. "There are other things going on." As part of much larger study to investigate the functional health of older people, called the Health ABC Study, Kritchevsky and his research team followed the health and activity levels of more than 3,000 people in their 70's over four years. "We asked them what kinds of physical activity they did over the past two weeks and took a blood sample to find out kind of what genotype that they had," he explains. "And then we talked to this group every six months over the next four years." Regular exercise helped most of them gain or maintain their mobility. Kritchevsky says, "People who were physically active when we first talked with them maintained maintain walking ability much better than the people who weren't physically active." However, a small percentage developed mobility problems in spite of exercising. It turned out they had a variation in a gene called ACE (angiotensin converting enzyme), what the researchers refer to as a difference in the person's genetic make-up, or genotype. © ScienCentral, 2000-2005.

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: 8219 - Posted: 06.24.2010

Playing catch is a simple pleasure for Lisa Van Vleck and her two sons. But a rare genetic brain disorder called vanishing white matter disease (VWM) kept her oldest son, Nathan, on the sidelines. "He loved watching people play sports," says Lisa Van Vleck from Pittsford, NY. But now Nathan is a key player in helping researchers understand this debilitating disease. His brain cells have shown, for the first time, that the type of cells they expected to be defective are actually normal, while others, surprisingly, are not. A very happy, social kid, Nathan's slow speech development by age two gave the first signs to both his parents and his pediatrician that something was wrong. "At first his gait was a little awkward, but he could walk — we thought he was normal," Van Vleck says. "But all the tests came back normal and everyone was just baffled. We went on for years like that." Tragically, in spite of some gains along the way, Nathan's decline was steady, confining him to a walker and then a wheelchair to get around. "It was very hard to watch," his mother recalls. "He realized it himself, he would say, 'Why can't I walk? I used to be able to walk.' And we didn't have any answers for him." After a nearly lifelong fight with this incredibly rare inherited disease, Nathan died at age 12. The family allowed doctors to immediately sample his brain cells. "We'd do anything to help so some other child wouldn't have to suffer," says Van Vleck. © ScienCentral, 2000-2005.

Related chapters from BN: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 4: Development of the Brain
Link ID: 7934 - Posted: 06.24.2010