Progress Daily

Dean Ornish, et al., just published a study (”Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention“) showing that improved nutrition, stress management techniques, walking, and psychosocial support changed the expression of over 500 genes in men with early-stage prostate cancer.

The researchers studied gene expression in biopsies from 30 men who were diagnosed with low-risk prostate cancer. These men had decided not to undergo conventional treatments such as surgery, radiation, or chemotherapy for reasons unrelated to the study. They had early, small-volume prostate cancer with stable prostate specific antigen (PSA) levels and Gleason scores of six or less, meaning that their tumors were not aggressive.

The changes included a plant-based diet (predominant fruits, vegetables, legumes, soy products, and whole grains low in refined carbohydrates), moderate exercise (walking 30 minutes per day), stress management techniques (yoga-based stretching, breathing techniques, meditation, and guided imagery for one hour per day), and participating in a weekly one-hour support group. The diet was supplemented with soy, fish oil (three grams/day), vitamin E (100 units/day), selenium (200 mg/day), and vitamin C (2 grams/day).

After three months, the researchers repeated the biopsy and looked at changes in normal tissue within the prostate. We found that many disease-promoting genes (including those associated with cancer, heart disease, and inflammation) were down-regulated or “turned off,” whereas protective, disease-preventing genes were up-regulated or “turned on.” A set of cancer-promoting oncogenes called RAS was down-regulated. The Selectin E gene (which promotes inflammation and is elevated in breast cancer) was down-regulated. A gene called SFRP that suppresses tumor formation was up-regulated. These genes are the target of many new drugs that are being developed.

“Changing Your Lifestyle Can Change Your Genes,” by Dean Ornish M.D.

About one in 20 children have a group of symptoms that has come to be known as attention-deficit hyperactivity disorder (ADHD). About 60% of them carry those symptoms into adulthood. ADHD is believed to be genetic, and is associated with particular variants of receptor molecules for neurotransmitters (chemicals that carry messages between nerve cells) in the brain. In the case of ADHD, the neurotransmitter is often dopamine, which controls feelings of reward and pleasure. People with ADHD apparently receive positive neurological feedback for “inappropriate” behaviour.

ADHD sufferers are impulsive. They have trouble concentrating on any task unless they receive constant feedback, stimulation and reward. They tend to perform poorly in modern society and are prone to addictive and compulsive behaviour.

Dan Eisenberg speculated that such behavior may be advantageous for people who lead a peripatetic life. Since today’s sedentary city dwellers are recently descended from such people, natural selection may not have had time to purge the genes that cause it.

Eisenberg tested this by studying the Ariaal, a group of pastoral nomads who live in Kenya. The receptor Mr Eisenberg looked at was the 7R variant of a protein called DRD4, a variant is associated with novelty-seeking, food- and drug-cravings, and ADHD. (See “Dopamine receptor genetic polymorphisms and body composition in undernourished pastoralists.”)

The researchers looked for 7R in two groups of Ariaal. One was still pastoral and nomadic. The other had recently settled down. They found that about a fifth of the population of both groups had the 7R version of DRD4. However, the consequences of this were very different. Among the nomads, who wander around northern Kenya herding cattle, camels, sheep and goats, those with 7R were better nourished than those without. Among their settled relations, those with 7R were worse nourished than those without it.

This discovery fits past findings that 7R and a set of similar variants of DRD4 (the “long alleles”) are more common in migratory populations.

There remains the question of why 7R is found in only a fifth of the Ariaal population. One possibility is that its effects are beneficial only when they are not universal, and some sort of equilibrium between variants emerges.

“The misfits,” The Economist

 

Using selective breeding, researchers can make rats, bees and flies a lot better at learning. Animals that are better learners should over time come to dominate a population. Yet improved learning ability does not get selected amongst these animals in the wild. Tadeusz Kawecki may have discovered why.

Kawecki gave flies two different fruits as egg laying sites. One of these was laced with a bitter additive that could be detected only on contact. The flies were then given the same fruit but without an additive. Flies that avoided the fruit which had been bitter were deemed to have learned from their experience. Their offspring were reared and the experiment was run again.

After repeating the experiment for 30 generations, the offspring of the learned flies were compared with normal flies. Learning ability was bred into the flies, but it shortened their lives by 15%. And when flies were bread to live abnormally long lives, they learned less well than even average flies.

“Critical thinking,” The Economist

Reading the 3bn “base pairs” in human DNA — akin to letters, encoding a total of between 20,000 and 30,000 genes that are the “words” of genetics — is getting faster as companies find quicker ways to “read” entire stretches of DNA at a time, like reading a sentence in chunks rather than letter by letter.

The cost of sequencing an individual genome is thus falling exponentially — just as the cost of hard disk space or transistors on a chip did when computing took off.

The rapidly falling cost and time needed to map your DNA:

2003
$440M
13 years to map

2007
$10M
4 years

2008
$100K
4 weeks

2012
$100*
2 days

*Forecast

“Mapping the individual - cheaply,” by Charles Arthur

As human societies grow richer, people have fewer children. In most species, such an increase in available resources leads in the opposite reproductive direction. What makes the “demographic transition” even more paradoxical is that in less developed times and places, the rich do not have smaller families than the poor.

Most explanations of the demographic transition are social, and none is really satisfactory.

A study by Agnar Helgason, of deCODE Genetics, has recently provided a new explanation: that the mixing-up of people caused by the urbanisation which normally accompanies development is, itself, partly responsible — because it breaks up optimal mating patterns.

Iceland’s records since its founding by a few Vikings are so good that the antecedents of today’s inhabitants (apart from a handful of recent immigrants) are known with precision. Its medical records are also good, and most Icelanders have given genetic samples to deCode.

The study’s principal finding is that the most fecund marriages are between distant cousins. The optimum degree of outbreeding (measured in terms of the number of children and grandchildren produced) lay somewhere between cousins of the third and fourth degrees.

(”Kissing cousins, missing children,” The Economist)

Icelandic women born between 1800 and 1824 who mated with a third cousin had significantly more children and grandchildren (4.0 and 9.2, respectively) than women who hooked up with someone no closer than an eighth cousin (3.3 and 7.3). Those proportions held up among women born more than a century later when couples were, on average, having fewer children.

Despite the general pattern for reproductive success favoring close kinship, couples that were second cousins or more closely related did not have as many children.

With close inbreeding — between first cousins — there is a significant increase in the probability that both partners will share one or more detrimental recessive genes, leading to a 25 percent chance that these genes will be expressed in each pregnancy.

Mating with a relative might reduce a woman’s chance of having a miscarriage caused by immunological incompatibility between a mother and her child. Some individuals have an antigen (a protein that can launch an immune response) on the surface of their red blood cells called a rhesus factor. In some cases — typically during a second pregnancy — when a woman gets pregnant, she and her fetus may have incompatible blood cells, which could trigger the mother’s immune system to treat the fetus as a foreign intruder, causing a miscarriage. This occurrence is less probable if the parents are closely related, because their blood makeup is more likely to match.

It may be that the enhanced reproductive success at the level of third and fourth cousins (who on average would be expected to have inherited 0.8 percent to 0.2 percent of their genes from a common ancestor) represents a point of balance between the competing advantages and disadvantages of inbreeding and outbreeding.

(”When Incest Is Best,” by Nikhil Swaminathan)

According to “Marketing actions can modulate neural representations of experienced pleasantness,” by Antonio Rangel, Hilke Plassmann, & Baba Shiv, if people are told a wine is expensive while they are drinking it, they think it tastes nicer than a cheap one.

The researchers used fmri (functional magnetic-resonance imaging) to scan the brains of 20 volunteers while giving them sips of wine.

Dr Rangel gave his volunteers sips of what he said were 5 different wines made from cabernet sauvignon grapes, priced at between $5 and $90 a bottle. He told each of them the price of the wine in question as he did so. But he lied. He actually used only 3 wines, and served two of them twice at different prices.

The scanner showed that the activity of the medial orbitofrontal cortices (an area of the brain responsible for registering pleasant experiences) of the volunteers increased in line with the stated price of the wine. When one of the wines was said to cost $10 a bottle it was rated less than half as good as when people were told it cost $90 a bottle, its true retail price. When the team carried out a follow-up blind tasting without price information they got different results. The volunteers reported differences between the three “real” wines but not between the same wines when served twice.

Nor was the effect confined to everyday drinkers. When Dr Rangel repeated the experiment on members of the Stanford University wine club he got similar results.

This research suggests that a successful marketing campaign can not only make people more interested in a product, but also make them enjoy it more.

“Hitting the spot,” The Economist

Givers are happier people than non-givers. According to the Social Capital Community Benchmark Survey, a survey of 30,000 American households, people who gave money to charity in 2000 were 43% more likely than non-givers to say they were “very happy” about their lives.

Similarly, volunteers were 42% more likely to be very happy than non-volunteers. It didn’t matter whether gifts of money and time went to churches or symphony orchestras — givers to all types of religious and secular causes were far happier than non-givers.

According to the University of Michigan’s Panel Study of Income Dynamics, people who gave money away in 2001 were 34% less likely than non-givers to say that they had felt “so sad that nothing could cheer them up” in the past month. They were also 68% less likely to have felt “hopeless,” and 24% less likely to have said that “everything was an effort.”

15% of Americans donate blood at least once each year.

According to the National Opinion Research Center’s General Social Survey, in 2002, 43% of the American adults who gave blood 2 to 3 times during the year said they were very happy versus only 29% of those who did not give blood.

Researchers have conducted experiments in which people are queried about their happiness before and after — sometimes long after — they participate in a charitable activity, such as volunteering to help children or serving meals to the poor. The result: giving has a causal impact on happiness.

In one 1998 experiment at Duke University, adults were asked to give massages to babies — the idea being that giving a baby pleasure is a compassionate act with no expectation of a reward, even a “thank you” — in return. After they performed the massages, the seniors were found to have dramatically lower levels of the stress hormones cortisol, epinephrine, and norepinephrine in their brains.

“Why Giving Makes You Happy,” by Arthur Brooks

According to new research by Bruce T. Lahn and Sarah Tishkoff, microcephalin and ASPM, two genes involved in determining the size of the human brain, have undergone substantial evolution in the last 60,000 years.

The researchers studied the worldwide distribution of the two genes’ alleles by decoding the DNA of the microcephalin and ASPM in many different populations.

With microcephalin, a new allele arose about 37,000 years ago, although it could have appeared as early as 60,000 or as late as 14,000 years ago. About 70% of people in most European and East Asian populations carry this allele of the gene, but it is much rarer in most sub-Saharan Africans.

With ASPM, a new allele emerged about 5,800 years ago (14,000 to 500 years ago). The allele has attained a frequency of about 50% in populations of the Middle East and Europe, is less common in East Asia, and is found at low frequency in some sub-Saharan Africa peoples.

The ASPM allele emerged about the same time as the spread of agriculture in the Middle East 10,000 years ago and the emergence of the civilizations of the Middle East some 5,000 years ago.

Dr Tishkoff said the statistical signature of selection on the two genes was “one of the strongest that I’ve seen.”

“Brain May Still Be Evolving, Studies Hint,” by Nicholas Wade

Only a decade after their commercial introduction, genetically modified (”GM”) crops are now cultivated in 22 countries on an area more than 4 times the size of Britain, by over 10 million farmers, of whom 9 million are resource-poor farmers in developing countries, mainly India and China. Most of these small-scale farmers grow pest-resistant GM cotton. In India, production tripled last year. GM cotton benefits farmers because it reduces the need for insecticides, thereby increasing their income and improving their health.

Every academy of science — the Indian, Chinese, Mexican, Brazilian, French and US academies as well as the UK’s Royal Society — has confirmed that there is no evidence of risk to human health from GM crops. In 2001, the research directorate of the EU commission released a summary of 81 scientific studies financed the EU, and conducted over a 15-year period: none found evidence of harm to humans or to the environment.

Researchers at PG Economics studied the global effects of GM crops (”Global Impact of Biotech Crops“), and concluded that the “environmental impact” of pesticide and herbicide use in GM-growing countries had been reduced by 15% and 20% respectively. Energy-intensive cultivation is being replaced by no-till or low-till agriculture. More than a 1/3 of the soya bean crop grown in the US is now grown in unploughed fields. Apart from using less energy, avoiding the plough improves soil quality, causes less disturbance to life within it and diminishes the emission of methane and other greenhouse gases. The study concluded that “the carbon savings from reduced fuel use and soil carbon sequestration in 2005 were equal to removing 4m cars from the road….”

James Lovelock has estimated that if all farming became organic, we would only be able to feed 1/3 the present world population.

“The real GM food scandal,” by Dick Taverne

Place a rat in a cage with an electrified floor and subject it to repeated shocks; it will show many signs of stress, at first flinging itself against the walls with each shock. But after a while, it just sits there apathetically, showing no inclination to escape from its painful prison. When autopsied, it will be found to have oversized adrenal glands and, frequently, stomach ulcers, both indicating serious stress.

Now repeat the experiment, but with a wooden stick in the cage alongside the rat. When shocked, the rat chews on the stick, and as a result, it can endure its experience much longer without burnout. At autopsy, its adrenal glands are smaller, stomach ulcers fewer.

Put 2 rats in the electrified cage. Shock them both. They snarl and fight. At autopsy, their adrenal glands are normal, and, even though they have experienced numerous shocks, they have no ulcers.

Recently physiologists have uncovered the hormonal basis for such behavior. Animals and people subjected to attack or threat experience “subordination stress,” as a result of which their adrenal hormones go up, along with blood pressure and the probability of developing ulcers. But when given the opportunity to “take it out” on someone else, victims show no sign of stress.

“The Targets of Aggression,” by David P. Barash