Showing posts from 2009

The looming crisis in human genetics

Nov 13th 2009
From The World in 2010 print edition
Full article:

By Geoffrey Miller
University of New Mexico

In a nutshell: the new genetics will reveal much less than hoped about how to cure disease, and much more than feared about human evolution and inequality, including genetic differences between classes, ethnicities and races....

Dozens of papers will report specific genes associated with almost every imaginable trait—intelligence, personality, religiosity, sexuality, longevity, economic risk-taking, consumer preferences, leisure interests and political attitudes. The data are already collected, with DNA samples from large populations already measured for these traits....

When sequencing costs drop within a few years below $1,000 per genome, researchers in Europe, China and India will start huge projects with vast sample sizes, sophisticated bioinformatics, diverse trait measures and detailed family struct…

Let’s celebrate human genetic diversity

By Bruce Lahn
Department of Human Genetics, University of Chicago

Lanny Ebenstein
Department of Economics,University of California at Santa Barbara

Nature 461, 726-728 (8 October 2009) | doi:10.1038/461726a; Published online 7 October 2009

Science is finding evidence of genetic diversity among groups of people as well as among individuals. This discovery should be embraced, not feared, say Bruce T. Lahn and Lanny Ebenstein.

A growing body of data is revealing the nature of human genetic diversity at increasingly finer resolution. It is now recognized that despite the high degree of genetic similarities that bind humanity together as a species, considerable diversity exists at both individual and group levels (see box, page 728). The biological significance of these variations remains to be explored fully. But enough evidence has come to the fore to warrant the question: what if scientific data ultimately demonstrate that genetically based biological va…

The Young and the Neuro

By David Brooks
New York Times
October 12, 2009

...In 2001, an Internet search of the phrase “social cognitive neuroscience” yielded 53 hits. Now you get more than a million on Google. Young scholars have been drawn to this field from psychology, economics, political science and beyond in the hopes that by looking into the brain they can help settle some old arguments about how people interact.

These people study the way biology, in the form of genes, influences behavior. But they’re also trying to understand the complementary process of how social behavior changes biology. Matthew Lieberman of U.C.L.A. is doing research into what happens in the brain when people are persuaded by an argument.

Keely Muscatell, one of his doctoral students, and others presented a study in which they showed people from various social strata some images of menacing faces. People whose parents had low social status exhibited more activation in the amygdala (the busy little part of the brain involved in fear…

Unlearning Stress

August 18, 2009
Brain Is a Co-Conspirator in a Vicious Stress Loop

....[N]ow researchers have discovered that the sensation of being highly stressed can rewire the brain in ways that promote its sinister persistence.

...Reporting earlier this summer in the journal Science, Nuno Sousa of the Life and Health Sciences Research Institute at the University of Minho in Portugal and his colleagues described experiments in which chronically stressed rats lost their elastic rat cunning and instead fell back on familiar routines and rote responses, like compulsively pressing a bar for food pellets they had no intention of eating.

...[R]egions of the brain associated with executive decision-making and goal-directed behaviors had shriveled, while, conversely, brain sectors linked to habit formation had bloomed...

“Behaviors become habitual faster in stressed animals than in the controls, and worse, the stressed animals can’t shift back to goal-directed behavi…

Personality Decided At Birth, Say Scientists

New Zealand Herald

4:00AM Monday Apr 13, 2009
By Steve Connor

Pessimism and shyness is one of four categories scientists investigated.

Personality types are linked with structural differences in the brain - which could explain why one child grows up to be impulsive and outgoing while another becomes diligent and introspective.

Anatomical differences between the brains of 85 people have been measured and linked with the four main categories of personality types as defined by psychiatrists using a clinically recognised system of character evaluation.

The researchers said the brain differences are structural and can be measured as variations in the size of specific regions of the brain that appear to be linked with each of the four personality types.

Brain scans that measure differences in volume down to an accuracy of less than one cubic millimetre found, for instance, that people defined as novelty-seeking personalities had a structurally bigger area of the brain above the eye sockets, known …

Intelligence is Largely Inherited

Study gives more proof that intelligence is largely inherited
UCLA researchers find that genes determine brain's processing speed
Mark Wheeler
UCLA Newsroom

They say a picture tells a thousand stories, but can it also tell how smart you are? Actually, say UCLA researchers, it can.

In a study published in the Journal of Neuroscience Feb. 18, UCLA neurology professor Paul Thompson and colleagues used a new type of brain-imaging scanner to show that intelligence is strongly influenced by the quality of the brain's axons, or wiring that sends signals throughout the brain. The faster the signaling, the faster the brain processes information. And since the integrity of the brain's wiring is influenced by genes, the genes we inherit play a far greater role in intelligence than was previously thought.

Genes appear to influence intelligence by determining how well nerve axons are encased in myelin — the fatty sheath of "insulation" that coats our axons and allows fo…

Are You Meant to Be a Bachelor?

Researchers find men with a certain gene are less likely to be married

Men's Health
By: Abby Lerner

If the thought of being in a committed relationship makes you break out into a sweat, there's nothing wrong with you—you may just be programmed to be single.

Swedish researchers looked at variants of a particular gene—the “monogamy gene”—that encodes for a hormone called vasopressin and found that one of these variants (or a lack thereof) is associated with a distinctive kind of pair-bonding behavior in men. The findings suggest an explanation for why some men commit to monogamous relationships while others have a hard time shaking their frat-house habits.

Men who carried only one copy of the “monogamy gene” were more likely to be unmarried or to report some form of marital crisis within the last year, compared to similar men without the gene. Those with two copies of the variant were more than twice as likely to have a dysfunctional marriage, according to the study from the Karo…

'Warrior gene' predicts aggressive behavior after provocation

January 21st, 2009 in Medicine & Health / Genetics

Individuals with the so-called "warrior gene" display higher levels of aggression in response to provocation, according to new research co-authored by Rose McDermott, professor of political science at Brown University. . . .

Monoamine oxidase A is an enzyme that breaks down important neurotransmitters in the brain, including dopamine, norepinephrine, and serotonin. The enzyme is regulated by monoamine oxidase A gene (MAOA). Humans have various forms of the gene, resulting in different levels of enzymatic activity. People with the low-activity form (MAOA-L) produce less of the enzyme, while the high-activity form (MAOA-H) produces more of the enzyme.

Several studies have found a correlation between the low-activity form of MAOA and aggression in observational and survey-based studies. Only about a third of people in Western populations have the low-activity form of MAOA. By comparison, low-activity MAOA has been reported to …